Airworthiness Directives; The Boeing Company Airplanes, 67837-67851 [2019-26736]

Download as PDF Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations of the local flight standards district office/ certificate holding district office. (2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or EASA; or Dassault Aviation’s EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature. (j) Related Information For more information about this AD, contact Tom Rodriguez, Aerospace Engineer, International Section, Transport Standards Branch, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone and fax 206– 231–3226. (k) Material Incorporated by Reference khammond on DSKJM1Z7X2PROD with RULES (1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless this AD specifies otherwise. (i) European Union Aviation Safety Agency (EASA) AD 2019–0273, dated November 4, 2019. (ii) [Reserved] (3) For information about EASA AD 2019– 0273, contact the EASA, Konrad-AdenauerUfer 3, 50668 Cologne, Germany; telephone +49 221 89990 6017; email ADs@ easa.europa.eu; Internet www.easa.europa.eu. You may find this EASA AD on the EASA website at https:// ad.easa.europa.eu. (4) You may view this material at the FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206–231–3195. This material may be found in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA–2019–0973. (5) You may view this material that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email fedreg.legal@ nara.gov, or go to: https://www.archives.gov/ federal-register/cfr/ibr-locations.html. Issued in Des Moines, Washington, on November 21, 2019. Dorr Anderson, Acting Director, System Oversight Division, Aircraft Certification Service. [FR Doc. 2019–26704 Filed 12–11–19; 8:45 am] BILLING CODE 4910–13–P VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2017–1024; Product Identifier 2017–NM–065–AD; Amendment 39–19746; AD 2019–19–10] RIN 2120–AA64 Airworthiness Directives; The Boeing Company Airplanes Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 737–300, –400, –500, –600, –700, –700C, –800, –900, and –900ER series airplanes; Model 757 series airplanes; Model 767 series airplanes; Model 777 series airplanes; and Model 787–8 and 787–9 airplanes. This AD was prompted by reports of fuel crossfeed valves failing to open when activated during flight. This AD requires, for certain airplanes, revising the existing airplane flight manual (AFM); and for certain other airplanes, revising the existing minimum equipment list (MEL) to do an operational check of the fuel crossfeed valve prior to each extended operations (ETOPS) flight if one fuel crossfeed valve (or the fuel balancing system on Model 787 airplanes) is inoperative. The FAA is issuing this AD to address the unsafe condition on these products. DATES: This AD is effective January 16, 2020. ADDRESSES: SUMMARY: Examining the AD Docket You may examine the AD docket on the internet at https:// www.regulations.gov by searching for and locating Docket No. FAA–2017– 1024; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the regulatory evaluation, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE, Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Jon Regimbal, Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206– 231–3557; email: Jon.Regimbal@faa.gov. SUPPLEMENTARY INFORMATION: PO 00000 Frm 00011 Fmt 4700 Sfmt 4700 67837 Discussion The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all The Boeing Company Model 737–300, –400, –500, –600, –700, –700C, –800, –900, and –900ER series airplanes; Model 757 series airplanes; Model 767 series airplanes; Model 777 series airplanes; and Model 787–8 and 787–9 airplanes. The NPRM published in the Federal Register on December 5, 2017 (82 FR 57383). The NPRM was prompted by reports of fuel crossfeed valves failing to open when activated during flight. The NPRM proposed to require, for certain airplanes, revising the existing AFM; and for certain other airplanes, revising the existing MEL to do an operational check of the fuel crossfeed valve prior to each ETOPS flight if one fuel crossfeed valve (or the fuel balancing system on Model 787 airplanes) is inoperative. The FAA is issuing this AD to prevent an airplane from being dispatched on an ETOPS flight with a single fuel crossfeed valve (due to design or due to MEL dispatch of a dual crossfeed valve equipped airplane with one crossfeed valve inoperative) that cannot be opened or a fuel balancing system that cannot properly operate when activated. This condition could cause the fuel in the main tank associated with a failed engine to be unavailable to the remaining operative engine, potentially resulting in a forced off-airport landing due to exhaustion of the remaining usable fuel and consequent loss of all engine thrust. Comments The FAA gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the NPRM and the FAA’s response to each comment. Request To Withdraw the NPRM United Airlines (UAL) and Delta Air Lines (DAL) asked that the NPRM be withdrawn until corrective action is proposed with an adequate level of safety. UAL stated that the FAA processes leading to issuing the NPRM did not include certain expected elements (e.g., risk analysis, adequate cost analysis [which the FAA addresses in the ‘‘Request to Increase Cost Estimate’’ comment], and consideration for airplanes equipped with aircraft health monitoring (AHM) [which the FAA addresses in the ‘‘Request to Exclude Airplanes with AHM’’ comment]). UAL added that it is not aware of an FAA risk E:\FR\FM\12DER1.SGM 12DER1 khammond on DSKJM1Z7X2PROD with RULES 67838 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations analysis of a simultaneous engine failure and a crossfeed valve failure during an ETOPS flight in a critical fuel location. UAL conducted a risk analysis and provided the following comments and questions: • The NPRM specified that the FAA had received reports of fuel crossfeed valves failing to open when activated during flight, but provided no data. • The NPRM provided no statistical analysis of industry engine failure rates, or of crossfeed valve failure rates. What is the probability that an engine will fail and a crossfeed valve will fail on the same ETOPS flight in a fuel-critical location? • ETOPS-qualified aircraft engine failure rates are extremely low. UAL engine failure rates vary from 0.005 to 0.000, well below the 0.030 required for ETOPS certification. • Crossfeed valve failure rates are extremely low (roughly 1 per 100,000 departures), and Boeing had indicated that it did not regard the failure of crossfeed valves as a potential reliability issue. DAL stated that a Boeing risk analysis showed that an engine shutdown with the inability to transfer fuel is improbable (the FAA infers that the commenter meant ‘‘extremely improbable’’ as used in FAA risk analysis policy) and that Boeing does not consider this to be a safety issue. DAL added that cycling the fuel crossfeed valve prior to further flight, or at any time, does not ensure that the valve will work as intended at a later point in flight. DAL concluded that the proposed AD does not provide corrective action that will improve the safety of the airplane. The FAA does not agree to withdraw the NPRM. The FAA determined that the unsafe condition of fuel crossfeed valves failing to open or fuel balancing systems failing to operate when activated during flight must be addressed. For transport airplanes, this determination is based on several criteria, and the failure to meet one or more of the criteria could lead the FAA to determine that corrective action is warranted. For each identified potential safety issue on a transport airplane, the FAA examines the risk on the worst reasonably anticipated flights (flights actually predicted to occur) to ensure that each flight provides an acceptable level of safety [identified as ‘‘individual flight risk’’ in FAA risk analysis policy]. That acceptable level of safety consists of three basic expectations: • That each flight begins in a fail-safe state (including consideration of latent VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 failure conditions and allowed dispatch states under the MEL), meaning that a foreseeable single failure on any anticipated flight should not have a significant likelihood of causing a catastrophic event. • That each flight does not have a numerical risk of a catastrophic event due to the issue being examined that is excessively (an order of magnitude or more) greater than the risk of a catastrophic event on an average transport airplane. • That safety features that were prescriptively required due to lessons learned from past incidents and accidents are not excessively reduced in their effectiveness or availability. Failure to meet any of these three criteria can lead to a determination that an unsafe condition exists and AD action is necessary, because the level of safety on the affected flights does not meet the FAA’s thresholds for an acceptable level of safety on individual flights. For each identified potential safety issue, the FAA also assesses the total cumulative risk of an event occurring at any time in the remaining life of the fleet of affected airplanes (identified as ‘‘total fleet risk’’ in FAA risk analysis policy). The FAA may determine that corrective action is needed to limit total fleet risk even when the assessed individual flight risk does not violate any of the three individual flight risk criteria discussed above. Total fleet risk is typically assessed by multiplying the average probabilities of each of the failures or other factors that contribute to the occurrence of an event, the total number of airplanes affected, the average utilization of those airplanes, and the average remaining life for those airplanes. The FAA also considers the number of occupants of an aircraft in assessing fleet risk, and applies total fleet risk guideline thresholds expressed in terms of both aircraft accidents and number of fatalities. Either excessive individual flight risk or excessive total fleet risk, or both, can lead the FAA to determine that an unsafe condition exists that requires corrective action. The FAA does not use or accept calculations of acceptable total fleet risk, or acceptable average perflight-hour risk, as a justification for taking no action on issues where an excessive individual flight risk is determined to exist on flights that are anticipated to occur. For this AD, the FAA identified that flights of airplanes with a single operative crossfeed valve (due to design or due to MEL dispatch of a dual crossfeed valve equipped airplane with one crossfeed valve inoperative) are PO 00000 Frm 00012 Fmt 4700 Sfmt 4700 expected to occur with a pre-existing undetected failure of that single crossfeed valve (or of the fuel balancing system on Boeing Model 787 airplanes). On such a flight, if an engine shutdown occurs during the fuel-critical ETOPS portion of the flight, it can lead to fuel exhaustion and a forced off-airport landing. That fuel-critical portion of the flight can be of significant duration. For example, according to Boeing, the fuelcritical exposure window (during which an engine failure without crossfeed capability would lead to fuel exhaustion prior to reaching a suitable airport under the current 14 CFR part 121 fuel reserve requirements) ranges from approximately 1.8 to 2.3 hours in length for flights between the West Coast of the U.S. and Hawaii. For ETOPS missions using greater-than-180-minute ETOPS capability, the exposure can be significantly greater. While the average probability per flight hour of a failure of the crossfeed valve and an engine failure in cruise on the same flight has been shown by Boeing to be extremely improbable (on the order of one event per billion flight hours), the actual risk is not evenly spread among flights at the average level. Instead, most of that risk is currently concentrated in the flights of airplanes operating with a single crossfeed valve due to design configuration or MEL dispatch relief, and on which that single crossfeed valve is inoperative due to a latent failure. On such flights, the estimated average probability of an engine failure during the cruise phase of flight is in the range of one event per 100,000 to 1 million flight hours (based on current industry in-flight engine shutdown data), depending on the engine/airplane combination. In addition, engine shutdowns can be caused by many different single failures of engine or airplane components, which means those flights that begin with an already inoperative crossfeed valve are not failsafe for an engine failure as required by the airworthiness regulations and expected by the public. Based on the crossfeed valve actuator failure rates supplied by the Boeing and the current AFM requirements to check the operation of the crossfeed valves in the last hour of cruise on ETOPS flights, the FAA estimates that well over 100 flights with inoperative crossfeed valves will occur in the remaining life of the affected fleet. Such flights do not provide the level of safety that is intended for ETOPS operations. Checking the operation of the crossfeed valve immediately prior to each ETOPS flight will ensure that each flight begins with a crossfeed valve that was recently E:\FR\FM\12DER1.SGM 12DER1 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations verified to operate, and will minimize the likelihood of a crossfeed valve failing if engine crossfeed is required. The FAA considers a check of the crossfeed valve operation prior to each ETOPS flight to be a significant improvement in safety for the flights on which the risk is actually concentrated, thereby minimizing the chance that an engine failure on one of those flights will lead to a catastrophic fuel exhaustion event. For the reasons specified previously, the FAA is issuing this final rule to address the identified unsafe condition. Request To Revise Airplanes Affected by Certain Requirements American Airlines generally supported the NPRM, but asked that the airplanes affected by paragraphs (h) and (j) of the proposed AD be corrected. American Airlines stated that paragraphs (h) and (j) of the proposed AD specify airplanes having line numbers 1 through 616 inclusive and 618; however, the effectivity specified in Boeing Service Bulletin 757–28–0029 for the corresponding actions is line numbers 1 through 518 inclusive. American Airlines added that airplanes having line numbers above 518 had the actions specified in the referenced service information incorporated in production. The FAA agrees with the commenter’s request for the reason provided. Paragraphs (h) and (j) of this AD have been changed accordingly. khammond on DSKJM1Z7X2PROD with RULES Effect of Winglets on Accomplishment of the Proposed Actions Aviation Partners Boeing (APB) stated that the installation of winglets per Supplemental Type Certificate (STC) ST01219SE, ST00830SE, ST01518SE, or ST01920SE does not affect the accomplishment of the manufacturer’s service instructions. The FAA agrees that STC ST01219SE, ST00830SE, ST01518SE, and ST01920SE do not affect the accomplishment of the manufacturer’s service instructions. Therefore, the installation of STC ST01219SE, ST00830SE, ST01518SE, or ST01920SE does not affect the ability to accomplish the actions required by this AD. The AD has not been changed in this regard. Request To Increase Cost Estimate UAL stated that the FAA did not include adequate cost analysis and stated the FAA should consider the negative effects of daily activation of the crossfeed valve on mean time between failure (MTBF) rates, or the associated cost of increased valve replacement rates. VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 The FAA infers that UAL is asking that the cost estimate in the ‘‘Costs of Compliance’’ section of this final rule be increased to account for a decreased MTBF for the crossfeed valve or actuator. The FAA does not agree to increase the estimated costs. The FAA normally addresses only the direct cost of a required action, and the agency has not received any data from the manufacturer or operators indicating that actuating the crossfeed valve prior to each ETOPS flight will significantly increase the crossfeed valve failure and replacement rate. Relative to the effects of daily activation of the crossfeed valve, a significant decrease in MTBF will likely not result from the actions in this AD, for the following reasons: • The various fuel system valves and valve actuators are all of similar designs, and some of those valves are cycled once or more per flight. They are designed to operate for many thousands of cycles without failure. • For airplanes equipped with a single crossfeed valve, the existing AFM requires operators to perform an operational check of the crossfeed valve in the last hour of cruise of every ETOPS flight. This AD requires the same check to be performed prior to each ETOPS flight, and provides relief from the existing requirement for a valve operational check in the last hour of cruise. • For airplanes with dual crossfeed valves or a fuel balancing system (for Boeing Model 787 airplanes), this AD requires a crossfeed valve operational check only when the airplane is operated under the MEL with a crossfeed valve or fuel balance system inoperative. Therefore, this AD will not require a significantly increased total number of valve operational checks to be performed; the AD just changes when the check is performed. In light of these factors, this AD has not been changed in this regard. Request To Exclude Airplanes With AHM UAL asked to revise the applicability of the proposed AD to exclude airplanes that have an AHM system capable of reporting an impending crossfeed valve failure before an actual service failure occurs. UAL did not provide a reason for its request, but the FAA infers that the commenter considered that a system that can detect an impending crossfeed valve failure before an actual crossfeed valve failure occurs, leading to a precautionary crossfeed valve or actuator replacement, would provide an PO 00000 Frm 00013 Fmt 4700 Sfmt 4700 67839 acceptable way to address the unsafe condition. The FAA does not agree with the commenter’s request. The FAA is not aware of any of the affected airplanes having the capability to detect and annunciate an impending crossfeed valve failure. UAL did not identify a specific airplane or installed system feature that has that capability. Operators may apply for an alternative method of compliance (AMOC) in accordance with paragraph (o) of this AD, provided they can show that such a system is available for installation on an airplane and adequately addresses the unsafe condition. The AD has not been changed in this regard. Request To Allow Alternative AFM Approval Southwest Airlines (SWA) contended that use of the term ‘‘identical’’ in paragraph (g)(2) of the proposed AD would be unnecessarily restrictive and could prevent operators from using previously accepted formatting standards and layout. SWA therefore asked that paragraph (g)(2) of the proposed AD be revised to add the following statement: ‘‘Alternative statements that meet the intent of the following requirements may be used if approved by an appropriate FAA POI.’’ SWA added that a similar principal operations inspector (POI) allowance was provided in AD 2011–18–03, Amendment 39–16785 (76 FR 53317, August 26, 2011). The FAA does not agree with the commenter’s request. The intent of this AD is for the text of the general AFM revision limitations and procedures to be identical to that required by the AD; however, formatting and layout can be changed without an approved AMOC as long as those changes do not change the text of the statements. Operators may apply for an AMOC in accordance with paragraph (o) of this AD for any changes to the text required by the AD. The AD has not been changed in this regard. Request To Include Certain Provisions Required by Original Type Design Boeing asked that paragraph (n) of the proposed AD be changed to eliminate certain existing requirements for airplanes on which a last-hour-ofETOPS-flight crossfeed valve operational check is in the AFM as part of the type certificate approval. Boeing stated that after publication of AD 88– 21–03 R1, Amendment 39–6077 (53 FR 46605, November 18, 1988) (‘‘AD 88– 21–03 R1’’), new airplane models with a single crossfeed valve that were not affected by the requirements in AD 88– 21–03 R1 had a similar requirement in E:\FR\FM\12DER1.SGM 12DER1 67840 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations khammond on DSKJM1Z7X2PROD with RULES the AFM as part of the airplane type certificate. The FAA does not agree with the commenter’s request. The FAA approval of the AFM change proposed by the commenter would be considered an approval of a voluntary change to a type certificate. Such changes are required to be approved under the process defined in 14 CFR part 21 and are not accomplished through an AD. Once the operational check prior to each ETOPS flight is incorporated into the existing AFM or MEL as required by this AD, the check required in the last hour of cruise by the existing AFM could be eliminated through a type certificate design change approval. If Boeing or an operator wants to obtain approval of a revised AFM without the limitation requiring the last-hour-of-ETOPS-flight crossfeed valve operational check, the request can be submitted for FAA approval using the normal process for obtaining approval of a revised AFM. Therefore, the AD has not been changed in this regard. Request To Revise Headings for Certain Figures Boeing asked that the FAA expand the headings for the AFM text in figure 3 to paragraph (h)(1) of the proposed AD and figure 5 to paragraph (i)(1) of the proposed AD by adding ‘‘The following is applicable prior to incorporation of Boeing Service Bulletin 757–28–0029 or production equivalent,’’ and ‘‘The following is applicable prior to incorporation of Boeing Service Bulletin 757–28–0034 or production equivalent,’’ respectively. Boeing stated that the referenced service information and production equivalent are closing actions for the applicable AD. The FAA partially agrees with the commenter’s request. The FAA agrees to change these headings, because an operator could have a mixed fleet of single- and dual-valve airplane configurations operating under a single AFM version, which should have limitation language that is applicable only to airplanes with a single crossfeed valve. However, the FAA does not agree with making the specific change by referencing only service bulletins or production equivalent configurations, because while limitations with similar language have been approved in the past, the flight crew does not have readily available information on the service bulletins or production changes that are installed. However, the crew can readily identify whether the airplane has one or two crossfeed valves simply by looking at the overhead fuel control panel, where either one or two crossfeed valve switches are installed. VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 Therefore, the referenced headings in this AD have been changed to refer to the crossfeed valve configuration rather than the service bulletin number. Request To Eliminate the Operational Requirement in the MMEL Boeing asked that the proposed operational requirement for airplanes with dual crossfeed valves operating on the master minimum equipment list (MMEL) be eliminated. Boeing stated that after publication of AD 88–21–03, which required operational checks of the crossfeed valves in the last hour of each ETOPS flight for airplanes equipped with a single crossfeed valve, the FAA approved the installation of a second crossfeed valve as an AMOC for that AD, without requiring any crossfeed valve checks if the airplane is operated with a crossfeed valve inoperative under the MEL. Boeing added that it is not necessary to now mandate an operational check for an airplane operating with a crossfeed valve inoperative under the MEL. Boeing stated that the fundamental criterion for MMEL relief is that an acceptable level of safety must be maintained considering the next critical single failure event in flight. Boeing also stated that operation with a crossfeed valve or transfer system inoperative under the current MMEL requires verification that the remaining crossfeed valve is operative, and that in-flight failure of the remaining crossfeed valve during a subsequent flight would not itself create an unsafe condition. Boeing added that issuing an AD to require operational checks for operation under the MMEL is therefore redundant. Boeing cited the preamble language required by the FAA in MMEL Policy Letter 34, Revision 4, dated August 15, 1997: Experience has shown that with the various levels of redundancy designed into aircraft, operation of every system or installed component may not be necessary when the remaining operative equipment can provide an acceptable level of safety. Boeing stated that the addition of a redundant crossfeed valve provides a fault-tolerant configuration, which experience has shown provides an acceptable level of safety. Boeing concluded that unless credit is given for the redundant crossfeed valve without a requirement for an operational check, the redundant valve provides no added safety benefit and therefore could be eliminated. The FAA does not agree with the commenter’s request. When the FAA determines that an existing MMEL relief provision does not provide an acceptable level of safety, the FAA may PO 00000 Frm 00014 Fmt 4700 Sfmt 4700 either eliminate or modify that relief through AD action. In this case, the FAA determined that an operational check of the crossfeed valve, prior to each ETOPS flight that takes place with a single crossfeed valve, is necessary to prevent dispatch of an ETOPS flight with no ability to access all of the remaining fuel in the event of an engine failure. The FAA has further determined that flights without the ability to access all of the remaining fuel would not provide an acceptable level of safety, because a single engine failure during the critical portion of the cruise phase could result in a forced offairport landing due to inadequate usable fuel available to the operative engine. This check is necessary when an airplane equipped with a dual crossfeed valve is dispatched under the MMEL with one crossfeed valve inoperative or with the fuel balancing system inoperative, for the same reason that the crossfeed valve operational check is required prior to each ETOPS flight on an airplane with a single crossfeed valve. The citation from MMEL Policy Letter 34 is from the standardized language required by that policy letter to be included in the preamble of an MMEL. It is simply an introductory statement indicating that redundant systems may allow for dispatch with certain equipment inoperative in some cases. It is not intended to restrict the conditions or limitations that the FAA may place on a particular MMEL relief provision. The failure of a crossfeed valve in a manner that will prevent it from actuating is typically detected only through subsequent attempted actuation of the crossfeed valve for fuel balancing, or for crossfeed in the event of an engine failure. Therefore, the failure of the crossfeed valve is likely to remain undiscovered from the time of the failure until the next attempt at actuation. This latency period may occur during several flights in some operational situations, such as movement of an individual airplane to an ETOPS route when that airplane has previously been operated on nonETOPS routes. That operational situation and the associated latency period increases the likelihood that the crossfeed valve on that airplane will fail when the next attempt is made to actuate the crossfeed valve. An operational check of the crossfeed valve immediately prior to each ETOPS flight (the flights where the ability to open the crossfeed valve may be critical) is a practical measure to minimize the likelihood that the crossfeed valve will fail to open if needed, and to ensure that E:\FR\FM\12DER1.SGM 12DER1 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations the flight is started with an operative crossfeed valve. The addition of a second crossfeed valve provides redundancy that the FAA determined in the past was an acceptable substitute for a preflight operational check, and that also could allow for dispatch with one crossfeed valve inoperative. However, since that time the FAA has determined that when an airplane is operated with a crossfeed valve (or a fuel balancing system) under the MEL, it should be operated with the same crossfeed valve operational check requirement as an airplane with a single crossfeed valve configuration, for the same reason that the preflight operational check is required for an airplane with a single crossfeed valve configuration. Therefore, the AD has not been changed in this regard. khammond on DSKJM1Z7X2PROD with RULES Request To Correct Errors in Figure 10 Boeing, UAL, All Nippon Airways (ANA), and Captain David Stewart (Captain Stewart) asked that the language specified in figure 10 to paragraph (m) of the proposed AD be corrected to reflect that the allowed MMEL dispatch relief in that figure is for the fuel balance system instead of the crossfeed valve. UAL listed four specific MMEL provisions (specified in paragraphs (m)(1) through (4) of this AD) that are for various inoperative components or systems that cause the fuel balance system to be inoperative. Boeing and ANA stated that the figure should be revised to reflect that if the crossfeed valve fails to open, the FUEL CROSSFEED advisory message will not be displayed until 15 seconds after crossfeed is selected ON. Captain Stewart stated that the language in figure 10 to paragraph (m) of the proposed AD is erroneous and should have stated ‘‘Before the next ETOPS departure after the Fuel Balance Switch is determined to be inoperative . . . .’’ The FAA agrees with the commenters’ requests for the reasons provided. Figure 10 to paragraph (m) of this AD has been revised to correct the errors noted by the commenters. Request To Revise the MMEL Operational Check Requirements United Airlines MEL Engineering asked that the MMEL operational check requirements in figure 4 to paragraph (h)(2) of the proposed AD, figure 6 to paragraph (i)(2) of the proposed AD, figure 7 to paragraph (j) of the proposed AD, and figure 8 to paragraph (k) of the proposed AD be revised to allow the use of either the ‘‘VALVE’’ light that is integral to the crossfeed valve switch, or the associated engine indication and crew alerting system (EICAS) message VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 for the preflight operational check. UAL stated that if the ‘‘VALVE’’ light is inoperative, it would be unable to perform the check. UAL noted that MMEL relief is provided for the crossfeed valve lights. The FAA does not agree with the commenter’s request to perform the check using the ‘‘FWD/AFT FUEL CROSSFEED’’ EICAS message because there are certain crossfeed valve actuator failure modes that can cause the crossfeed valve to remain closed without the ‘‘FWD/AFT FUEL CROSSFEED’’ EICAS message being displayed. Short of directly observing the valve actuator, monitoring the VALVE light to verify that the crossfeed valve actually transitioned from closed to open is the only way to verify from the flight deck that the crossfeed valve transitioned to the open position. While MMEL relief is provided for the VALVE light, that relief is subject to the provision that the crossfeed valve is verified to operate correctly. The FAA does agree to allow an alternative procedure that is effective if the ‘‘VALVE’’ light is inoperative, because it is possible to perform an operational check of the crossfeed valve by directly observing the movement of the actuator if the ‘‘VALVE’’ light is inoperative. The FAA has revised the referenced figures in this AD accordingly. Request To Revise Crossfeed Valve Operational Check The Air Line Pilots Association, International (ALPA), Allied Pilots Association (APA), and Captain Stewart asked for revisions to the operational checks specified in the proposed AD. Captain Stewart asked that certain crossfeed valve actions in the proposed AD be changed to require one of the following: (1) Performing the crossfeed valve operational check in flight, prior to entering the ETOPS segment of the flight, and diverting the airplane to a suitable airport if the check fails, or (2) opening the crossfeed valve prior to entry into the ETOPS segment, leaving the crossfeed valve open throughout the ETOPS segment, and diverting the airplane to a suitable airport if the valve fails to open. Captain Stewart pointed out that operation with the crossfeed valve open for the duration of the ETOPS portion of the flight was proven effective at a major airline. ALPA, while supporting the inclusion of an operational check prior to dispatch of ETOPS flights, stated that since the action in the proposed AD is not directed at a specific crossfeed valve failure mode, and is instead intended to identify and minimize the exposure to PO 00000 Frm 00015 Fmt 4700 Sfmt 4700 67841 any crossfeed valve failure mode, it is important to check the crossfeed valve in its normal operating environment during flight. ALPA therefore requested that the proposed AD be revised to include an AFM requirement for airplanes with only one crossfeed valve, and a MEL requirement for airplanes with two crossfeed valves, for an operational check of the crossfeed valve during cruise, prior to the entering ETOPS airspace. APA had no objection to the steps for checking the crossfeed valve operation, using the procedure recommended by the original equipment manufacturer (OEM). APA recommended checking the crossfeed valve immediately prior to the ETOPS segment of the flight where its operation has the potential to be critical. The FAA does not agree with the commenters’ requests. Although the agency agrees that operationally checking the crossfeed valve immediately prior to entering the critical ETOPS portion of each ETOPS flight would provide a greater reduction in the risk that a crossfeed valve will fail to open in the fuel-critical phase of flight should an engine failure occur, it would also significantly increase the costs associated with each discovered failure of a crossfeed valve. The cost of an air turn-back or diversion is significantly higher than the cost of a delay for maintenance, and is likely to be greater than the cost of a flight cancellation. The FAA considered the additional costs that would be incurred by operators from an air turn-back or diversion each time a crossfeed valve fails its check, and also considered the additional reduction in exposure to latent crossfeed valve failures that develop between the time of a preflight check and the time of an ETOPS entry check. As a result of these considerations, the FAA determined that the incremental reduction in exposure to the development of a latent crossfeed valve failure due to checking the crossfeed valve in-flight prior to entry into the critical ETOPS portion of the flight, when the low probability of an engine failure is also considered, did not justify imposing those significant additional operational costs and service disruptions on affected operators. Before the NPRM was published, the FAA discussed with Boeing the value of conducting the crossfeed valve operational check during flight under cold soak conditions (which are part of the normal operating environment), versus performing the check on the ground. As a result of some of the comments on the NPRM, the agency discussed this issue again with Boeing, and placed a record of that discussion E:\FR\FM\12DER1.SGM 12DER1 67842 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations khammond on DSKJM1Z7X2PROD with RULES in the public rulemaking docket. Boeing stated that the valve actuator failure modes identified by other commenters that result in actuator failures only in cold soak conditions have been corrected in newer designs. Boeing further stated that the previous valve actuator configurations that had those issues are no longer in service. Boeing added that it had no reason to believe that a check of the current in-service crossfeed valves under cold, in-flight conditions would detect failures that would not be detected on the ground. In addition, the FAA does not agree with the request to require operation with the crossfeed valve open throughout the ETOPS segment of flight. While operation in that configuration would prevent the need to open the crossfeed valve in the event of an engine failure, there are other failure scenarios (such as a large fuel leak or contamination of one main tank) where operating with the crossfeed valve open compromises the intended isolation and independence of the fuel system for each engine. Also, differences in fuel pump performance could cause the need for repeated switching off and on of fuel pumps to maintain balanced main tanks. The FAA considers this undesirable because a flight crew error could put one or both engines on suction feed, potentially causing engine flameout. It would also add start/stop cycles on the fuel pumps, which could cause additional pump failures. Such a procedure is not recommended or approved by either Boeing or the FAA. Finally, that procedure violates the required fuel usage procedures in the limitations section of the FAA-approved AFMs for all of the affected airplane models, which require the airplane to be operated with the crossfeed valve closed except when it is specifically required to be open for crossfeeding to maintain balanced main tanks or for a low fuel condition. Therefore, that procedure would also violate 14 CFR 91.9, which requires operators to operate aircraft in accordance with their applicable AFM limitations, unless a revised AFM was approved. In light of all these factors, the AD has not been changed in this regard. Request To Change MMEL-Related Requirements Captain Stewart recommended that the proposed AD be revised to require an MMEL revision with clearly written provisions that identify the appropriate verification to confirm that no latent faults exist. Captain Stewart added that there is no benefit in mandating specific (M) & (O) procedures in the proposed AD, because it would cause an VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 unnecessary administrative burden. Captain Stewart concluded that MELs published without the adequate (M) & (O) procedures indicates a failure of the MEL review/approval process at the flight standards district office (FSDO) or certificate management office (CMO) level. The FAA infers that the commenter is requesting that the MEL entries for operation with an inoperative crossfeed valve or fuel balancing system (for Model 787 airplanes) state the requirement for and objectives of the MEL maintenance and operational requirements, rather than mandating specific maintenance or operational procedures. The FAA does not agree with the commenter’s request. In this case, there are various ways that the operational or maintenance check can be done, some of which would not detect all of the possible crossfeed valve failure modes. Therefore, the FAA has determined that the agency should maintain control over the operational and maintenance check procedures used. Operators may, however, apply for an AMOC in accordance with paragraph (o) of this AD, provided they can show that their proposed alternative operational or maintenance procedures adequately address the unsafe condition. The AD has not been changed in this regard. Request To Exempt Certain Airplanes FedEx asked that the proposed AD be revised to exclude airplanes that are not used for ETOPS operations from the proposed requirement to revise the existing AFM and MEL. Specifically, FedEx requested that paragraphs (h), (i), (j), and (k) of the proposed AD be revised to add ‘‘Airplanes that are not used for ETOPS operations are exempt from the requirements of this paragraph.’’ FedEx stated that the proposed AD does not allow for exemption of affected fleets that are not certified or utilized for ETOPS operations. FedEx reported that its fleets include the types of airplanes affected by the proposed AD, but that only its Model 777F airplanes are certified for ETOPS operations. The FAA does not agree with the commenter’s request. The addition of the language proposed by the commenter is not sufficient to ensure that the existing AFM and MEL will be updated as required by this AD if there is an operational change in the future. However, operators may apply for an AMOC in accordance with paragraph (o) of this AD, provided they submit a proposal that (1) describes how the operator will ensure that future introduction of ETOPS operations PO 00000 Frm 00016 Fmt 4700 Sfmt 4700 includes the required AFM and MEL changes and (2) is supported by its FAA POI. The AD has not been changed in this regard. Request To Clarify Instructions for Operational Check FedEx and Japan Airlines (JAL) asked that the language in figure 8 to paragraph (k) of the proposed AD be revised to include instructions for a fuel crossfeed valve operational check including ‘‘steps on the ground prior to engine start.’’ The commenters requested that ‘‘prior to engine start’’ be changed to ‘‘prior to each flight.’’ FedEx stated that this language should be clarified given that the intent of the proposed AD is to prevent fuel in the main tank associated with the failed engine from being unavailable to the remaining operative engine, potentially resulting in a forced off-airport landing. JAL stated that the time for performing the operational check in the proposed AD is more restrictive than that in the MMEL. JAL added that since both are the same action, that compliance time should be the same. The FAA acknowledges the commenters’ concerns regarding potential misunderstanding of when to perform the operational check, and agree that clarification is necessary. The FAA infers that FedEx found that figure 8 to paragraph (k) of this AD was not sufficiently clear that the operational check is intended to be performed prior to each flight. The FAA presumes that FedEx’s concern is that an operator might perform the operational check only once prior to the first engine start after placing the other inoperative crossfeed valve on MEL relief, but not prior to subsequent flights on the MEL. The intent of the procedure is that an operational check of the crossfeed valve be performed, by maintenance personnel or flightcrew, immediately prior to each ETOPS flight, as was stated in the ‘‘Proposed AD Requirements’’ section of the NPRM. The FAA disagrees with using the specific language proposed by FedEx because its language would not alleviate the confusion about the intent of the requirement, and might be interpreted as allowing the check to be performed at any time prior to flight, as opposed to immediately prior to each flight. Although the comment from FedEx requested a change to figure 8 to paragraph (k) of this AD, which provides the required MEL revision for the Model 767, the FAA is satisfied that the MEL language in figure 7 to paragraph (j) of this AD, figure 8 to paragraph (k) of this AD, figure 9 to paragraph (l) of this AD, and figure 10 E:\FR\FM\12DER1.SGM 12DER1 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations khammond on DSKJM1Z7X2PROD with RULES to paragraph (m) of this AD is clear with respect to the intended timing of performing the crossfeed valve operational check. The general intent of operational procedures in the existing MEL is that they are associated with each flight conducted with the inoperative equipment. However, the comments provided caused the agency to reconsider whether the corresponding language in the AFM revisions required for airplanes equipped with single crossfeed valves are sufficiently clear regarding the intended timing for the check. In light of this, figure 1 to paragraph (g)(1) of this AD, figure 3 to paragraph (h)(1) of this AD, and figure 5 to paragraph (i)(1) of this AD of this AD have been revised to clarify the AFM limitations on airplanes equipped with a single crossfeed valve. However, the language in other figures, including figure 8 to paragraph (k) of this AD, have not been changed. Request To Change Time for Performing Operational Check DAL asked that the time for performing the operational check be changed to the last hour of the cruise flight, instead of prior to each ETOPS flight. DAL stated that solder joint cracks at the connectors and electronic assembly could cause intermittent or hard fault failure of the motor-operated crossfeed valves (MOVs) that is difficult to detect during the ground test prior to each ETOPS flight. DAL added that a cold soak test at the end of the cruise flight will better detect intermittent MOV failures than a test performed on the ground. The FAA does not agree with the commenter’s request. At the FAA’s request, Boeing examined the commenter’s statements, and Boeing provided comments. A record of the phone conversation in which Boeing provided its comments was placed in the public rulemaking docket for this AD. Boeing stated that the valve actuator failure modes described by DAL that tended to occur in cold conditions were successfully addressed by design improvements, and that the valve actuator configurations that were susceptible to failures that could only be detected in cold conditions have been replaced on operational aircraft and are no longer in service. Boeing added that its more recent failure data shows that the timing of failures is random, and that the ability to detect a failed crossfeed valve is no longer significantly impacted by environmental conditions during the operational check. As previously discussed, the FAA has determined that the greatest practical VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 reduction in risk during operation with a single operational crossfeed valve would be achieved by requiring the operational check as close as possible to the beginning of the fuel-critical ETOPS portion of the flight. However, as noted, the impact of requiring the operational check in flight, just prior to entry into the ETOPS portion of the flight, would cause a significant number of air turnbacks and diversions at significant cost, so the FAA, with agreement from Boeing, proposed the check requirement for immediately prior to each ETOPS flight. Therefore, this AD has not been changed in this regard. Request To Reduce Compliance Time ALPA asked that the compliance time be reduced from 120 to 90 days. ALPA stated that the proposed AD would not require extensive, one-time maintenance actions on affected airplanes, but only revision of existing AFM and MEL actions, thus the commenter recommended a shorter compliance time. The FAA does not agree with the commenter’s request. In conjunction with Boeing, the FAA has determined that the compliance time for each airplane model will accommodate the time necessary to accomplish the actions required by this AD and maintain an adequate level of safety. In addition, the suggested compliance time change would alter the requirements of this AD, so additional rulemaking would be required, ultimately delaying issuance of the AD. The FAA finds that delaying this action further is inappropriate in light of the identified unsafe condition. However, if additional data are presented that would justify a shorter compliance time, the FAA may consider further rulemaking on this issue. The AD has not been changed in this regard. Request To Add Airplanes to Applicability American Airlines asked that Model 737–7, –8, and –9 (MAX) airplanes be added to the applicability of the proposed AD. American Airlines stated that the design on these airplanes is similar to that of the Model 737 Classic and Next Gen airplanes. The FAA does not agree with the request. Although the commenter is correct about the similar design, this unsafe condition was identified at the time of certification of the 737 MAX airplanes as a planned airworthiness directive against the existing Model 737 airplanes. Therefore, Boeing included the requirement for the operational check of the crossfeed valve required by this AD in the FAA-approved AFM for PO 00000 Frm 00017 Fmt 4700 Sfmt 4700 67843 the 737 MAX airplanes. The AD has not been changed in this regard. Engineering Oversight Captain Stewart and APA stated that it is an engineering oversight that new production ETOPS airplanes are being certificated with only one fuel crossfeed valve installed. The FAA acknowledges the commenter’s concern about the risk associated with two-engine ETOPS airplanes that depend on a single active component to allow the remaining engine to access all of the remaining fuel on board after an engine failure. However, the allowance for such designs was not an engineering oversight, but a result of how the initial 120-minute ETOPS type-design standards were developed with existing airplanes in mind, of the later 180minute ETOPS type-design standards being developed based on the 120minute standards, and of conscious decision making by Boeing and the FAA associated with AD 88–21–03 R1 (which applies to certain Airbus Model A300 and A310–200 series airplanes, and Boeing Model 737–200, 737–300, 757– 200, 767–200, and 767–300 series airplanes) and certification of the Model 737–700 airplane. Discussion of the potential need for improvements to airworthiness standards is outside the scope of the actions required by this AD. Therefore, the AD has not been changed in this regard. Report of Incident Commenter Amirul Ismail provided what appears to be a pilot report of an instance where an operational check of the crossfeed valve on a Model 737–800 airplane resulted in the VALVE light failing to extinguish. The incident appears to be an indication-related fault rather than a valve actuator failure. No change to the final rule has been made. Conclusion The FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule with the changes described previously and minor editorial changes. The FAA has determined that these minor changes: • Are consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and • Do not add any additional burden upon the public than was already proposed in the NPRM. The FAA also determined that these changes will not increase the economic burden on any operator or increase the scope of this final rule. E:\FR\FM\12DER1.SGM 12DER1 67844 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations Costs of Compliance The FAA estimates that this AD affects 3,252 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: ESTIMATED COSTS Labor cost AFM Revision (2,127 airplanes) ............................... MEL Revision (1,125 airplanes) ................................ 1 work-hour × $85 per hour = $85 ...... 1 work-hour × $85 per hour = $85 ...... Authority for This Rulemaking Title 49 of the United States Code specifies the FAA’s authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency’s authority. The FAA is issuing this rulemaking under the authority described in Subtitle VII, part A, subpart III, Section 44701: ‘‘General requirements.’’ Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes and associated appliances to the Director of the System Oversight Division. Regulatory Findings khammond on DSKJM1Z7X2PROD with RULES Parts cost Action This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. For the reasons discussed above, I certify that this AD: (1) Is not a ‘‘significant regulatory action’’ under Executive Order 12866, VerDate Sep<11>2014 16:56 Dec 11, 2019 Jkt 250001 (2) Will not affect intrastate aviation in Alaska, and (3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. Adoption of the Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39—AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: ■ Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD): ■ 2019–19–10 The Boeing Company: Amendment 39–19746; Docket No. FAA–2017–1024; Product Identifier 2017–NM–065–AD. (a) Effective Date This AD is effective January 16, 2020. (b) Affected ADs This AD affects AD 88–21–03 R1, Amendment 39–6077 (53 FR 46605, November 18, 1988) (‘‘AD 88–21–03 R1’’). (c) Applicability This AD applies to all The Boeing Company airplanes, certificated in any category, identified in paragraphs (c)(1) through (5) of this AD. (1) Model 737–300, –400, –500, –600, –700, –700C, –800, –900, and –900ER series airplanes. (2) Model 757–200, –200PF, –200CB, and –300 series airplanes. (3) Model 767–200, –300, –300F, and –400ER series airplanes. (4) Model 777–200, –200LR, –300, –300ER, and –777F series airplanes. (5) Model 787–8 and 787–9 airplanes. PO 00000 Frm 00018 Fmt 4700 Sfmt 4700 Cost per product $0 0 $85 85 Cost on U.S. operators $180,795 95,625 (d) Subject Air Transport Association (ATA) of America Code 28; Fuel. (e) Unsafe Condition This AD was prompted by reports of fuel crossfeed valves failing to open when activated during flight. The FAA is issuing this AD to prevent an airplane from being dispatched on an extended operations (ETOPS) flight with a single fuel crossfeed valve (due to design or due to minimum equipment list (MEL) dispatch of a dual crossfeed valve equipped airplane with one crossfeed valve inoperative) that cannot be opened or a fuel balancing system that cannot properly operate when activated. This condition could cause the fuel in the main tank associated with a failed engine to be unavailable to the remaining operative engine, potentially resulting in a forced off airport landing due to exhaustion of the remaining usable fuel and consequent loss of all engine thrust. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) AFM Revisions for Model 737 Airplanes Equipped With a Single Fuel Crossfeed Valve For airplanes identified in paragraph (c)(1) of this AD: Within 120 days after the effective date of this AD, do the actions specified in paragraphs (g)(1) and (2) of this AD. (1) Revise the ‘‘Extended Range Operations’’ subsection of the ‘‘Fuel System Limitations’’ section of the Section 1 Certificate Limitations of the existing airplane flight manual (AFM) by incorporating the information specified in figure 1 to paragraph (g)(1) of this AD. This may be done by inserting a copy of this AD into the existing AFM. When a statement identical to that in figure 1 to paragraph (g)(1) of this AD has been included in the ‘‘Extended Range Operations’’ subsection of the ‘‘Fuel System Limitations’’ section of the Section 1 Certificate Limitations of the general revisions of the existing AFM, the general revisions may be inserted into the existing AFM, and the copy of this AD may be removed from the existing AFM. E:\FR\FM\12DER1.SGM 12DER1 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations (2) Revise the ‘‘Extended Range Operations’’ section of the Section 3 Normal Procedures of the existing AFM by incorporating the information specified in figure 2 to paragraph (g)(2) of this AD. This may be done by inserting a copy of this AD into the existing AFM. When a statement identical to that in figure 2 to paragraph (g)(2) of this AD has been included in the ‘‘Extended Range Operations’’ section of Section 3 Normal Procedures of the existing AFM, the general revisions may be inserted into the existing AFM, and the copy of this AD may be removed from the existing AFM. (h) AFM Revisions for Model 757 Airplanes Equipped With a Single Fuel Crossfeed Valve this paragraph, if the actions specified in Boeing Service Bulletin 757–28–0029 have been done, the actions specified in this paragraph are no longer required for that airplane and the actions specified in paragraph (j) of this AD must be done before further flight after the actions specified in Boeing Service Bulletin 757–28–0029 have been performed. (1) Revise the ‘‘Extended Range Operations’’ section of the Section 1 Certificate Limitations of the existing AFM by incorporating the information specified in figure 3 to paragraph (h)(1). This may be done by inserting a copy of this AD into the existing AFM. When a statement identical to that in figure 3 to paragraph (h)(1) of this AD has been included in the ‘‘Extended Range Operations’’ section of the Section 1 Certificate Limitations of the general revisions of the existing AFM, the general revisions may be inserted into the existing AFM, and the copy of this AD may be removed from the existing AFM. VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 PO 00000 Frm 00019 Fmt 4700 Sfmt 4700 E:\FR\FM\12DER1.SGM 12DER1 ER12DE19.000</GPH> ER12DE19.001</GPH> For airplanes identified in paragraph (c)(2) of this AD having line numbers 1 through 518 inclusive, on which the actions specified in Boeing Service Bulletin 757–28–0029 (second fuel crossfeed valve installation) have not been done: Within 120 days after the effective date of this AD, do the actions specified in paragraphs (h)(1) and (2) of this AD. For Model 757 airplanes identified in khammond on DSKJM1Z7X2PROD with RULES 67845 67846 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations (2) Revise the ‘‘Extended Range Operations’’ section of Section 3 Normal Procedures of the existing AFM by incorporating the information specified in figure 4 to paragraph (h)(2) of this AD. This may be done by inserting a copy of this AD into the existing AFM. When a statement identical to that in figure 4 to paragraph (h)(2) of this AD has been included in the ‘‘Extended Range Operations’’ section of Section 3 Normal Procedures of the existing AFM, the general revisions may be inserted into the existing AFM, and the copy of this AD may be removed from the existing AFM. (i) AFM Revisions for Model 767 Airplanes Equipped With a Single Fuel Crossfeed Valve paragraphs (i)(1) and (2) of this AD. For airplanes on which the actions specified in Boeing Service Bulletin 767–28–0034 have been done, the actions specified in this paragraph are no longer required for that airplane and the actions specified in paragraph (k) of this AD must be done before further flight. (1) Revise the ‘‘Extended Range Operations’’ section of the Section 1 Certificate Limitations of the existing AFM by incorporating the information specified in figure 5 to paragraph (i)(1) of this AD. This may be done by inserting a copy of this AD into the existing AFM. When a statement identical to that in figure 5 to paragraph (i)(1) of this AD has been included in the ‘‘Extended Range Operations’’ section of the Section 1 Certificate Limitations of the general revisions of the existing AFM, the general revisions may be inserted into the existing AFM, and the copy of this AD may be removed from the existing AFM. ER12DE19.003</GPH> VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 PO 00000 Frm 00020 Fmt 4700 Sfmt 4700 E:\FR\FM\12DER1.SGM 12DER1 ER12DE19.002</GPH> khammond on DSKJM1Z7X2PROD with RULES For airplanes identified in paragraph (c)(3) of this AD having line numbers 1 through 430 inclusive on which the actions specified in Boeing Service Bulletin 767–28–0034 (second fuel crossfeed valve installation) have not been done as of the effective date of this AD: Within 120 days after the effective date of this AD, do the actions specified in Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations (2) Revise the ‘‘Extended Range Operations’’ section of Section 3.1 Normal Procedures of the existing AFM by incorporating the information specified in figure 6 to paragraph (i)(2) of this AD. This may be done by inserting a copy of this AD into the existing AFM. When a statement identical to that in figure 6 to paragraph (i)(2) of this AD has been included in the ‘‘Extended Range Operations’’ section of Section 3.1 Normal Procedures of the existing AFM, the general revisions may be inserted into the existing AFM, and the copy of this AD may be removed from the existing AFM. (j) MEL Revisions for Model 757 Airplanes Equipped With Dual Fuel Crossfeed Valves a second fuel crossfeed valve has been installed, as specified in Boeing Service Bulletin 757–28–0029: Within 120 days after the effective date of this AD, revise the operator’s existing FAA-approved MEL by incorporating the information specified in figure 7 to paragraph (j) of this AD as a required operations procedure when dispatching for ETOPS operation with an inoperative fuel crossfeed valve. Specific alternative MEL wording to accomplish the actions specified in figure 7 to paragraph (j) of this AD can be approved by the operator’s principal operations inspector (POI). VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 PO 00000 Frm 00021 Fmt 4700 Sfmt 4700 E:\FR\FM\12DER1.SGM 12DER1 ER12DE19.004</GPH> ER12DE19.005</GPH> For airplanes identified in paragraph (c)(2) of this AD having line numbers 519 and subsequent; and for airplanes identified in paragraph (c)(2) of this AD having line numbers 1 through 518 inclusive, on which khammond on DSKJM1Z7X2PROD with RULES 67847 (k) MEL Revisions for Model 767 Airplanes Equipped With Dual Fuel Crossfeed Valves khammond on DSKJM1Z7X2PROD with RULES For airplanes identified in paragraph (c)(3) of this AD having line numbers 431 and subsequent; and for airplanes identified in paragraph (c)(3) of this AD having line numbers 1 through 430 inclusive on which (l) MEL Revisions for Model 777 Airplanes For airplanes identified in paragraph (c)(4) of this AD: Within 120 days after the effective date of this AD, revise the operator’s existing FAA-approved MEL by incorporating the VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 a second fuel crossfeed valve has been installed, as specified in Boeing Service Bulletin 767–28–0034: Within 120 days after the effective date of this AD, revise the operator’s existing FAA-approved MEL by incorporating the information specified in figure 8 to paragraph (k) of this AD as a required operations procedure when dispatching for ETOPS operation with an inoperative fuel crossfeed valve. Specific alternative MEL wording to accomplish the actions specified in figure 8 to paragraph (k) of this AD can be approved by the operator’s POI. information specified in figure 9 to paragraph (l) of this AD as a required operations procedure when dispatching for ETOPS operation with an inoperative fuel crossfeed valve. Specific alternative MEL wording to accomplish the actions specified in figure 9 to paragraph (l) of this AD can be approved by the operator’s POI. PO 00000 Frm 00022 Fmt 4700 Sfmt 4700 E:\FR\FM\12DER1.SGM 12DER1 ER12DE19.007</GPH> Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations ER12DE19.006</GPH> 67848 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations khammond on DSKJM1Z7X2PROD with RULES For airplanes identified in paragraph (c)(5) of this AD: Within 120 days after the effective date of this AD, revise the operator’s existing FAA-approved MEL by incorporating the information specified in figure 10 to VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 paragraph (m) of this AD into the MEL requirements for each of the inoperative items specified in paragraphs (m)(1) through (4) of this AD. Specific alternative MEL wording to accomplish the actions specified in figure 10 to paragraph (m) of this AD can be approved by the operator’s POI. PO 00000 Frm 00023 Fmt 4700 Sfmt 4700 (1) 28–21–01–01 Pressure Refueling System, Main Tank Inboard Refuel Valve. (2) 28–22–06 Fuel Balance Switch. (3) 28–26–01 Defuel/Isolation Valves. (4) 28–41–01–01 Main Tank Fuel Quantity Indication Systems. E:\FR\FM\12DER1.SGM 12DER1 ER12DE19.008</GPH> (m) MEL Revisions for Model 787 Airplanes 67849 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations khammond on DSKJM1Z7X2PROD with RULES (n) AD 88–21–03 R1 AFM Limitation Removal After the applicable AFM limitations specified in paragraphs (g)(1), (h)(1), and (i)(1) of this AD are incorporated into an airplane’s existing AFM, operators may remove the AFM limitation required by AD 88–21–03 R1, for that airplane. (o) Alternative Methods of Compliance (AMOCs) (1) The Manager, Seattle ACO Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your VerDate Sep<11>2014 16:05 Dec 11, 2019 Jkt 250001 principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the certification office, send it to the attention of the person identified in paragraph (p) of this AD. Information may be emailed to: 9-ANMSeattle-ACO-AMOC-Requests@faa.gov. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/ certificate holding district office. (3) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by The Boeing Company Organization Designation Authorization PO 00000 Frm 00024 Fmt 4700 Sfmt 4700 (ODA) that has been authorized by the Manager, Seattle ACO Branch, FAA, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD. (p) Related Information For more information about this AD, contact Jon Regimbal, Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206–231–3557; email: Jon.Regimbal@faa.gov. E:\FR\FM\12DER1.SGM 12DER1 ER12DE19.009</GPH> 67850 Federal Register / Vol. 84, No. 239 / Thursday, December 12, 2019 / Rules and Regulations (q) Material Incorporated by Reference None. Issued in Des Moines, Washington, on October 3, 2019. Michael Kaszycki, Acting Director, System Oversight Division, Aircraft Certification Service. [FR Doc. 2019–26736 Filed 12–11–19; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2019–0494; Product Identifier 2019–NM–051–AD; Amendment 39–19801; AD 2019–23–07] RIN 2120–AA64 Airworthiness Directives; The Boeing Company Airplanes Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: Discussion The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 787–8, 787–9, and 787–10 airplanes. This AD was prompted by reports that the nose landing gear (NLG) retracted on the ground, with weight on the airplane’s wheels, due to the incorrect installation of an NLG downlock pin in the apex pin inner bore of the NLG lock link assembly. This AD requires installing an insert to prevent installation of the pin in the incorrect location. The FAA is issuing this AD to address the unsafe condition on these products. DATES: This AD is effective January 16, 2020. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of January 16, 2020. ADDRESSES: For service information identified in this final rule, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110–SK57, Seal Beach, CA 90740–5600; telephone 562–797–1717; internet https://www.myboeingfleet.com. You may view this service information at the FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206–231–3195. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA–2019–0494. khammond on DSKJM1Z7X2PROD with RULES SUMMARY: VerDate Sep<11>2014 16:05 Dec 11, 2019 Examining the AD Docket You may examine the AD docket on the internet at https:// www.regulations.gov by searching for and locating Docket No. FAA–2019– 0494; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the regulatory evaluation, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE, Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Allen Rauschendorfer, Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206–231–3528; email: allen.rauschendorfer@faa.gov. SUPPLEMENTARY INFORMATION: Jkt 250001 The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 787–8, 787–9, and 787–10 airplanes. The NPRM published in the Federal Register on July 23, 2019 (84 FR 35352). The NPRM was prompted by reports that the NLG retracted on the ground, with weight on the airplane’s wheels, due to the incorrect installation of an NLG downlock pin in the apex pin inner bore of the NLG lock link assembly. The NPRM proposed to require installing an insert to prevent installation of the pin in the incorrect location. The FAA is issuing this AD to address the NLG downlock pin being incorrectly installed in the apex pin inner bore of the NLG lock link assembly, which could result in the NLG retracting on the ground, possibly causing serious injuries to personnel and passengers and substantial damage to the airplane. Comments The FAA gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the NPRM and the FAA’s response to each comment. Request To Revise Applicability of the Proposed AD American Airlines (AAL) requested that the FAA revise the applicability of the AD to specify the affected part numbers of the NLG lock link assembly rather than the affected airplanes PO 00000 Frm 00025 Fmt 4700 Sfmt 4700 67851 because the affected parts may be swapped between airplanes. AAL noted that paragraph A.2. of Boeing Requirements Bulletin B787–81205– SB320040–00 RB, Issue 001, dated March 12, 2019, specifies to identify, modify, and part mark the spares. AAL suggested that once the apex bin inner bore insert is installed in the NLG lock link assembly in production, the NLG lock link assembly part number should also change. AAL requested that, should the FAA not revise the applicability of the proposed AD to affected part numbers, the applicability of the proposed AD be revised to include all Model 787 airplanes rather than only the airplanes specified in Boeing Requirements Bulletin B787–81205– SB320040–00 RB, Issue 001, dated March 12, 2019. AAL asserted that the unsafe condition applies to all airplanes. The FAA disagrees with the request to revise the applicability of this AD. This AD does not require operators to identify, modify, or part mark their spares. Paragraph (g) of this AD specifies to accomplish the actions in accordance with the Accomplishment Instructions of Boeing Requirements Bulletin B787–81205–SB320040–00 RB, Issue 001, dated March 12, 2019, and does not specify to accomplish actions in accordance with paragraph A.2. of Boeing Requirements Bulletin B787– 81205–SB320040–00 RB, Issue 001, dated March 12, 2019. Therefore, the FAA has determined that it is appropriate for this AD to apply to Boeing Model 787–8, 787–9, 787–10 airplanes, line numbers 6 through 848 inclusive, as specified in Boeing Requirements Bulletin B787–81205– SB320040–00 RB, Issue 001, dated March 12, 2019. Only these airplanes need to have the apex bin inner bore insert installed in order to address the identified unsafe condition. Regarding AAL’s request to revise the applicability to all Model 787 airplanes, Boeing will incorporate the apex pin inner bore insert as part of the airplane type design at line number 849 and subsequent. At that time, the NLG lock link assembly will change part numbers, and the airplane type design will be changed as a result. If an operator installs an NLG lock link assembly of a different part number than what is defined as airplane type design, then the airplane would be out of compliance. Consequently, all airplanes will be required to have the apex pin inner bore insert installed in the NLG lock link assembly. No changes have been made to the applicability of this AD. E:\FR\FM\12DER1.SGM 12DER1

Agencies

[Federal Register Volume 84, Number 239 (Thursday, December 12, 2019)]
[Rules and Regulations]
[Pages 67837-67851]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-26736]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1024; Product Identifier 2017-NM-065-AD; Amendment 
39-19746; AD 2019-19-10]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model 737-300, -400, -500, -600, -700, -700C, -800, 
-900, and -900ER series airplanes; Model 757 series airplanes; Model 
767 series airplanes; Model 777 series airplanes; and Model 787-8 and 
787-9 airplanes. This AD was prompted by reports of fuel crossfeed 
valves failing to open when activated during flight. This AD requires, 
for certain airplanes, revising the existing airplane flight manual 
(AFM); and for certain other airplanes, revising the existing minimum 
equipment list (MEL) to do an operational check of the fuel crossfeed 
valve prior to each extended operations (ETOPS) flight if one fuel 
crossfeed valve (or the fuel balancing system on Model 787 airplanes) 
is inoperative. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective January 16, 2020.

ADDRESSES: 

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2017-
1024; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this final rule, the regulatory evaluation, any comments received, and 
other information. The address for Docket Operations is U.S. Department 
of Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Jon Regimbal, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3557; email: 
[email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all The Boeing Company 
Model 737-300, -400, -500, -600, -700, -700C, -800, -900, and -900ER 
series airplanes; Model 757 series airplanes; Model 767 series 
airplanes; Model 777 series airplanes; and Model 787-8 and 787-9 
airplanes. The NPRM published in the Federal Register on December 5, 
2017 (82 FR 57383). The NPRM was prompted by reports of fuel crossfeed 
valves failing to open when activated during flight. The NPRM proposed 
to require, for certain airplanes, revising the existing AFM; and for 
certain other airplanes, revising the existing MEL to do an operational 
check of the fuel crossfeed valve prior to each ETOPS flight if one 
fuel crossfeed valve (or the fuel balancing system on Model 787 
airplanes) is inoperative.
    The FAA is issuing this AD to prevent an airplane from being 
dispatched on an ETOPS flight with a single fuel crossfeed valve (due 
to design or due to MEL dispatch of a dual crossfeed valve equipped 
airplane with one crossfeed valve inoperative) that cannot be opened or 
a fuel balancing system that cannot properly operate when activated. 
This condition could cause the fuel in the main tank associated with a 
failed engine to be unavailable to the remaining operative engine, 
potentially resulting in a forced off-airport landing due to exhaustion 
of the remaining usable fuel and consequent loss of all engine thrust.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Request To Withdraw the NPRM

    United Airlines (UAL) and Delta Air Lines (DAL) asked that the NPRM 
be withdrawn until corrective action is proposed with an adequate level 
of safety.
    UAL stated that the FAA processes leading to issuing the NPRM did 
not include certain expected elements (e.g., risk analysis, adequate 
cost analysis [which the FAA addresses in the ``Request to Increase 
Cost Estimate'' comment], and consideration for airplanes equipped with 
aircraft health monitoring (AHM) [which the FAA addresses in the 
``Request to Exclude Airplanes with AHM'' comment]). UAL added that it 
is not aware of an FAA risk

[[Page 67838]]

analysis of a simultaneous engine failure and a crossfeed valve failure 
during an ETOPS flight in a critical fuel location.
    UAL conducted a risk analysis and provided the following comments 
and questions:
     The NPRM specified that the FAA had received reports of 
fuel crossfeed valves failing to open when activated during flight, but 
provided no data.
     The NPRM provided no statistical analysis of industry 
engine failure rates, or of crossfeed valve failure rates. What is the 
probability that an engine will fail and a crossfeed valve will fail on 
the same ETOPS flight in a fuel-critical location?
     ETOPS-qualified aircraft engine failure rates are 
extremely low. UAL engine failure rates vary from 0.005 to 0.000, well 
below the 0.030 required for ETOPS certification.
     Crossfeed valve failure rates are extremely low (roughly 1 
per 100,000 departures), and Boeing had indicated that it did not 
regard the failure of crossfeed valves as a potential reliability 
issue.
    DAL stated that a Boeing risk analysis showed that an engine 
shutdown with the inability to transfer fuel is improbable (the FAA 
infers that the commenter meant ``extremely improbable'' as used in FAA 
risk analysis policy) and that Boeing does not consider this to be a 
safety issue. DAL added that cycling the fuel crossfeed valve prior to 
further flight, or at any time, does not ensure that the valve will 
work as intended at a later point in flight. DAL concluded that the 
proposed AD does not provide corrective action that will improve the 
safety of the airplane.
    The FAA does not agree to withdraw the NPRM. The FAA determined 
that the unsafe condition of fuel crossfeed valves failing to open or 
fuel balancing systems failing to operate when activated during flight 
must be addressed. For transport airplanes, this determination is based 
on several criteria, and the failure to meet one or more of the 
criteria could lead the FAA to determine that corrective action is 
warranted.
    For each identified potential safety issue on a transport airplane, 
the FAA examines the risk on the worst reasonably anticipated flights 
(flights actually predicted to occur) to ensure that each flight 
provides an acceptable level of safety [identified as ``individual 
flight risk'' in FAA risk analysis policy]. That acceptable level of 
safety consists of three basic expectations:
     That each flight begins in a fail-safe state (including 
consideration of latent failure conditions and allowed dispatch states 
under the MEL), meaning that a foreseeable single failure on any 
anticipated flight should not have a significant likelihood of causing 
a catastrophic event.
     That each flight does not have a numerical risk of a 
catastrophic event due to the issue being examined that is excessively 
(an order of magnitude or more) greater than the risk of a catastrophic 
event on an average transport airplane.
     That safety features that were prescriptively required due 
to lessons learned from past incidents and accidents are not 
excessively reduced in their effectiveness or availability.
    Failure to meet any of these three criteria can lead to a 
determination that an unsafe condition exists and AD action is 
necessary, because the level of safety on the affected flights does not 
meet the FAA's thresholds for an acceptable level of safety on 
individual flights.
    For each identified potential safety issue, the FAA also assesses 
the total cumulative risk of an event occurring at any time in the 
remaining life of the fleet of affected airplanes (identified as 
``total fleet risk'' in FAA risk analysis policy). The FAA may 
determine that corrective action is needed to limit total fleet risk 
even when the assessed individual flight risk does not violate any of 
the three individual flight risk criteria discussed above. Total fleet 
risk is typically assessed by multiplying the average probabilities of 
each of the failures or other factors that contribute to the occurrence 
of an event, the total number of airplanes affected, the average 
utilization of those airplanes, and the average remaining life for 
those airplanes. The FAA also considers the number of occupants of an 
aircraft in assessing fleet risk, and applies total fleet risk 
guideline thresholds expressed in terms of both aircraft accidents and 
number of fatalities.
    Either excessive individual flight risk or excessive total fleet 
risk, or both, can lead the FAA to determine that an unsafe condition 
exists that requires corrective action. The FAA does not use or accept 
calculations of acceptable total fleet risk, or acceptable average per-
flight-hour risk, as a justification for taking no action on issues 
where an excessive individual flight risk is determined to exist on 
flights that are anticipated to occur.
    For this AD, the FAA identified that flights of airplanes with a 
single operative crossfeed valve (due to design or due to MEL dispatch 
of a dual crossfeed valve equipped airplane with one crossfeed valve 
inoperative) are expected to occur with a pre-existing undetected 
failure of that single crossfeed valve (or of the fuel balancing system 
on Boeing Model 787 airplanes). On such a flight, if an engine shutdown 
occurs during the fuel-critical ETOPS portion of the flight, it can 
lead to fuel exhaustion and a forced off-airport landing. That fuel-
critical portion of the flight can be of significant duration. For 
example, according to Boeing, the fuel-critical exposure window (during 
which an engine failure without crossfeed capability would lead to fuel 
exhaustion prior to reaching a suitable airport under the current 14 
CFR part 121 fuel reserve requirements) ranges from approximately 1.8 
to 2.3 hours in length for flights between the West Coast of the U.S. 
and Hawaii. For ETOPS missions using greater-than-180-minute ETOPS 
capability, the exposure can be significantly greater.
    While the average probability per flight hour of a failure of the 
crossfeed valve and an engine failure in cruise on the same flight has 
been shown by Boeing to be extremely improbable (on the order of one 
event per billion flight hours), the actual risk is not evenly spread 
among flights at the average level. Instead, most of that risk is 
currently concentrated in the flights of airplanes operating with a 
single crossfeed valve due to design configuration or MEL dispatch 
relief, and on which that single crossfeed valve is inoperative due to 
a latent failure. On such flights, the estimated average probability of 
an engine failure during the cruise phase of flight is in the range of 
one event per 100,000 to 1 million flight hours (based on current 
industry in-flight engine shutdown data), depending on the engine/
airplane combination. In addition, engine shutdowns can be caused by 
many different single failures of engine or airplane components, which 
means those flights that begin with an already inoperative crossfeed 
valve are not fail-safe for an engine failure as required by the 
airworthiness regulations and expected by the public.
    Based on the crossfeed valve actuator failure rates supplied by the 
Boeing and the current AFM requirements to check the operation of the 
crossfeed valves in the last hour of cruise on ETOPS flights, the FAA 
estimates that well over 100 flights with inoperative crossfeed valves 
will occur in the remaining life of the affected fleet. Such flights do 
not provide the level of safety that is intended for ETOPS operations. 
Checking the operation of the crossfeed valve immediately prior to each 
ETOPS flight will ensure that each flight begins with a crossfeed valve 
that was recently

[[Page 67839]]

verified to operate, and will minimize the likelihood of a crossfeed 
valve failing if engine crossfeed is required. The FAA considers a 
check of the crossfeed valve operation prior to each ETOPS flight to be 
a significant improvement in safety for the flights on which the risk 
is actually concentrated, thereby minimizing the chance that an engine 
failure on one of those flights will lead to a catastrophic fuel 
exhaustion event. For the reasons specified previously, the FAA is 
issuing this final rule to address the identified unsafe condition.

Request To Revise Airplanes Affected by Certain Requirements

    American Airlines generally supported the NPRM, but asked that the 
airplanes affected by paragraphs (h) and (j) of the proposed AD be 
corrected. American Airlines stated that paragraphs (h) and (j) of the 
proposed AD specify airplanes having line numbers 1 through 616 
inclusive and 618; however, the effectivity specified in Boeing Service 
Bulletin 757-28-0029 for the corresponding actions is line numbers 1 
through 518 inclusive. American Airlines added that airplanes having 
line numbers above 518 had the actions specified in the referenced 
service information incorporated in production.
    The FAA agrees with the commenter's request for the reason 
provided. Paragraphs (h) and (j) of this AD have been changed 
accordingly.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing (APB) stated that the installation of 
winglets per Supplemental Type Certificate (STC) ST01219SE, ST00830SE, 
ST01518SE, or ST01920SE does not affect the accomplishment of the 
manufacturer's service instructions.
    The FAA agrees that STC ST01219SE, ST00830SE, ST01518SE, and 
ST01920SE do not affect the accomplishment of the manufacturer's 
service instructions. Therefore, the installation of STC ST01219SE, 
ST00830SE, ST01518SE, or ST01920SE does not affect the ability to 
accomplish the actions required by this AD. The AD has not been changed 
in this regard.

Request To Increase Cost Estimate

    UAL stated that the FAA did not include adequate cost analysis and 
stated the FAA should consider the negative effects of daily activation 
of the crossfeed valve on mean time between failure (MTBF) rates, or 
the associated cost of increased valve replacement rates.
    The FAA infers that UAL is asking that the cost estimate in the 
``Costs of Compliance'' section of this final rule be increased to 
account for a decreased MTBF for the crossfeed valve or actuator. The 
FAA does not agree to increase the estimated costs. The FAA normally 
addresses only the direct cost of a required action, and the agency has 
not received any data from the manufacturer or operators indicating 
that actuating the crossfeed valve prior to each ETOPS flight will 
significantly increase the crossfeed valve failure and replacement 
rate.
    Relative to the effects of daily activation of the crossfeed valve, 
a significant decrease in MTBF will likely not result from the actions 
in this AD, for the following reasons:
     The various fuel system valves and valve actuators are all 
of similar designs, and some of those valves are cycled once or more 
per flight. They are designed to operate for many thousands of cycles 
without failure.
     For airplanes equipped with a single crossfeed valve, the 
existing AFM requires operators to perform an operational check of the 
crossfeed valve in the last hour of cruise of every ETOPS flight. This 
AD requires the same check to be performed prior to each ETOPS flight, 
and provides relief from the existing requirement for a valve 
operational check in the last hour of cruise.
     For airplanes with dual crossfeed valves or a fuel 
balancing system (for Boeing Model 787 airplanes), this AD requires a 
crossfeed valve operational check only when the airplane is operated 
under the MEL with a crossfeed valve or fuel balance system 
inoperative.
    Therefore, this AD will not require a significantly increased total 
number of valve operational checks to be performed; the AD just changes 
when the check is performed. In light of these factors, this AD has not 
been changed in this regard.

Request To Exclude Airplanes With AHM

    UAL asked to revise the applicability of the proposed AD to exclude 
airplanes that have an AHM system capable of reporting an impending 
crossfeed valve failure before an actual service failure occurs. UAL 
did not provide a reason for its request, but the FAA infers that the 
commenter considered that a system that can detect an impending 
crossfeed valve failure before an actual crossfeed valve failure 
occurs, leading to a precautionary crossfeed valve or actuator 
replacement, would provide an acceptable way to address the unsafe 
condition.
    The FAA does not agree with the commenter's request. The FAA is not 
aware of any of the affected airplanes having the capability to detect 
and annunciate an impending crossfeed valve failure. UAL did not 
identify a specific airplane or installed system feature that has that 
capability. Operators may apply for an alternative method of compliance 
(AMOC) in accordance with paragraph (o) of this AD, provided they can 
show that such a system is available for installation on an airplane 
and adequately addresses the unsafe condition. The AD has not been 
changed in this regard.

Request To Allow Alternative AFM Approval

    Southwest Airlines (SWA) contended that use of the term 
``identical'' in paragraph (g)(2) of the proposed AD would be 
unnecessarily restrictive and could prevent operators from using 
previously accepted formatting standards and layout. SWA therefore 
asked that paragraph (g)(2) of the proposed AD be revised to add the 
following statement: ``Alternative statements that meet the intent of 
the following requirements may be used if approved by an appropriate 
FAA POI.'' SWA added that a similar principal operations inspector 
(POI) allowance was provided in AD 2011-18-03, Amendment 39-16785 (76 
FR 53317, August 26, 2011).
    The FAA does not agree with the commenter's request. The intent of 
this AD is for the text of the general AFM revision limitations and 
procedures to be identical to that required by the AD; however, 
formatting and layout can be changed without an approved AMOC as long 
as those changes do not change the text of the statements. Operators 
may apply for an AMOC in accordance with paragraph (o) of this AD for 
any changes to the text required by the AD. The AD has not been changed 
in this regard.

Request To Include Certain Provisions Required by Original Type Design

    Boeing asked that paragraph (n) of the proposed AD be changed to 
eliminate certain existing requirements for airplanes on which a last-
hour-of-ETOPS-flight crossfeed valve operational check is in the AFM as 
part of the type certificate approval. Boeing stated that after 
publication of AD 88-21-03 R1, Amendment 39-6077 (53 FR 46605, November 
18, 1988) (``AD 88-21-03 R1''), new airplane models with a single 
crossfeed valve that were not affected by the requirements in AD 88-21-
03 R1 had a similar requirement in

[[Page 67840]]

the AFM as part of the airplane type certificate.
    The FAA does not agree with the commenter's request. The FAA 
approval of the AFM change proposed by the commenter would be 
considered an approval of a voluntary change to a type certificate. 
Such changes are required to be approved under the process defined in 
14 CFR part 21 and are not accomplished through an AD. Once the 
operational check prior to each ETOPS flight is incorporated into the 
existing AFM or MEL as required by this AD, the check required in the 
last hour of cruise by the existing AFM could be eliminated through a 
type certificate design change approval. If Boeing or an operator wants 
to obtain approval of a revised AFM without the limitation requiring 
the last-hour-of-ETOPS-flight crossfeed valve operational check, the 
request can be submitted for FAA approval using the normal process for 
obtaining approval of a revised AFM. Therefore, the AD has not been 
changed in this regard.

Request To Revise Headings for Certain Figures

    Boeing asked that the FAA expand the headings for the AFM text in 
figure 3 to paragraph (h)(1) of the proposed AD and figure 5 to 
paragraph (i)(1) of the proposed AD by adding ``The following is 
applicable prior to incorporation of Boeing Service Bulletin 757-28-
0029 or production equivalent,'' and ``The following is applicable 
prior to incorporation of Boeing Service Bulletin 757-28-0034 or 
production equivalent,'' respectively. Boeing stated that the 
referenced service information and production equivalent are closing 
actions for the applicable AD.
    The FAA partially agrees with the commenter's request. The FAA 
agrees to change these headings, because an operator could have a mixed 
fleet of single- and dual-valve airplane configurations operating under 
a single AFM version, which should have limitation language that is 
applicable only to airplanes with a single crossfeed valve. However, 
the FAA does not agree with making the specific change by referencing 
only service bulletins or production equivalent configurations, because 
while limitations with similar language have been approved in the past, 
the flight crew does not have readily available information on the 
service bulletins or production changes that are installed. However, 
the crew can readily identify whether the airplane has one or two 
crossfeed valves simply by looking at the overhead fuel control panel, 
where either one or two crossfeed valve switches are installed. 
Therefore, the referenced headings in this AD have been changed to 
refer to the crossfeed valve configuration rather than the service 
bulletin number.

Request To Eliminate the Operational Requirement in the MMEL

    Boeing asked that the proposed operational requirement for 
airplanes with dual crossfeed valves operating on the master minimum 
equipment list (MMEL) be eliminated. Boeing stated that after 
publication of AD 88-21-03, which required operational checks of the 
crossfeed valves in the last hour of each ETOPS flight for airplanes 
equipped with a single crossfeed valve, the FAA approved the 
installation of a second crossfeed valve as an AMOC for that AD, 
without requiring any crossfeed valve checks if the airplane is 
operated with a crossfeed valve inoperative under the MEL. Boeing added 
that it is not necessary to now mandate an operational check for an 
airplane operating with a crossfeed valve inoperative under the MEL.
    Boeing stated that the fundamental criterion for MMEL relief is 
that an acceptable level of safety must be maintained considering the 
next critical single failure event in flight. Boeing also stated that 
operation with a crossfeed valve or transfer system inoperative under 
the current MMEL requires verification that the remaining crossfeed 
valve is operative, and that in-flight failure of the remaining 
crossfeed valve during a subsequent flight would not itself create an 
unsafe condition. Boeing added that issuing an AD to require 
operational checks for operation under the MMEL is therefore redundant.
    Boeing cited the preamble language required by the FAA in MMEL 
Policy Letter 34, Revision 4, dated August 15, 1997:

    Experience has shown that with the various levels of redundancy 
designed into aircraft, operation of every system or installed 
component may not be necessary when the remaining operative 
equipment can provide an acceptable level of safety.

    Boeing stated that the addition of a redundant crossfeed valve 
provides a fault-tolerant configuration, which experience has shown 
provides an acceptable level of safety. Boeing concluded that unless 
credit is given for the redundant crossfeed valve without a requirement 
for an operational check, the redundant valve provides no added safety 
benefit and therefore could be eliminated.
    The FAA does not agree with the commenter's request. When the FAA 
determines that an existing MMEL relief provision does not provide an 
acceptable level of safety, the FAA may either eliminate or modify that 
relief through AD action. In this case, the FAA determined that an 
operational check of the crossfeed valve, prior to each ETOPS flight 
that takes place with a single crossfeed valve, is necessary to prevent 
dispatch of an ETOPS flight with no ability to access all of the 
remaining fuel in the event of an engine failure. The FAA has further 
determined that flights without the ability to access all of the 
remaining fuel would not provide an acceptable level of safety, because 
a single engine failure during the critical portion of the cruise phase 
could result in a forced offairport landing due to inadequate usable 
fuel available to the operative engine. This check is necessary when an 
airplane equipped with a dual crossfeed valve is dispatched under the 
MMEL with one crossfeed valve inoperative or with the fuel balancing 
system inoperative, for the same reason that the crossfeed valve 
operational check is required prior to each ETOPS flight on an airplane 
with a single crossfeed valve.
    The citation from MMEL Policy Letter 34 is from the standardized 
language required by that policy letter to be included in the preamble 
of an MMEL. It is simply an introductory statement indicating that 
redundant systems may allow for dispatch with certain equipment 
inoperative in some cases. It is not intended to restrict the 
conditions or limitations that the FAA may place on a particular MMEL 
relief provision. The failure of a crossfeed valve in a manner that 
will prevent it from actuating is typically detected only through 
subsequent attempted actuation of the crossfeed valve for fuel 
balancing, or for crossfeed in the event of an engine failure. 
Therefore, the failure of the crossfeed valve is likely to remain 
undiscovered from the time of the failure until the next attempt at 
actuation. This latency period may occur during several flights in some 
operational situations, such as movement of an individual airplane to 
an ETOPS route when that airplane has previously been operated on non-
ETOPS routes. That operational situation and the associated latency 
period increases the likelihood that the crossfeed valve on that 
airplane will fail when the next attempt is made to actuate the 
crossfeed valve. An operational check of the crossfeed valve 
immediately prior to each ETOPS flight (the flights where the ability 
to open the crossfeed valve may be critical) is a practical measure to 
minimize the likelihood that the crossfeed valve will fail to open if 
needed, and to ensure that

[[Page 67841]]

the flight is started with an operative crossfeed valve.
    The addition of a second crossfeed valve provides redundancy that 
the FAA determined in the past was an acceptable substitute for a 
preflight operational check, and that also could allow for dispatch 
with one crossfeed valve inoperative. However, since that time the FAA 
has determined that when an airplane is operated with a crossfeed valve 
(or a fuel balancing system) under the MEL, it should be operated with 
the same crossfeed valve operational check requirement as an airplane 
with a single crossfeed valve configuration, for the same reason that 
the preflight operational check is required for an airplane with a 
single crossfeed valve configuration. Therefore, the AD has not been 
changed in this regard.

Request To Correct Errors in Figure 10

    Boeing, UAL, All Nippon Airways (ANA), and Captain David Stewart 
(Captain Stewart) asked that the language specified in figure 10 to 
paragraph (m) of the proposed AD be corrected to reflect that the 
allowed MMEL dispatch relief in that figure is for the fuel balance 
system instead of the crossfeed valve. UAL listed four specific MMEL 
provisions (specified in paragraphs (m)(1) through (4) of this AD) that 
are for various inoperative components or systems that cause the fuel 
balance system to be inoperative. Boeing and ANA stated that the figure 
should be revised to reflect that if the crossfeed valve fails to open, 
the FUEL CROSSFEED advisory message will not be displayed until 15 
seconds after crossfeed is selected ON. Captain Stewart stated that the 
language in figure 10 to paragraph (m) of the proposed AD is erroneous 
and should have stated ``Before the next ETOPS departure after the Fuel 
Balance Switch is determined to be inoperative . . . .''
    The FAA agrees with the commenters' requests for the reasons 
provided. Figure 10 to paragraph (m) of this AD has been revised to 
correct the errors noted by the commenters.

Request To Revise the MMEL Operational Check Requirements

    United Airlines MEL Engineering asked that the MMEL operational 
check requirements in figure 4 to paragraph (h)(2) of the proposed AD, 
figure 6 to paragraph (i)(2) of the proposed AD, figure 7 to paragraph 
(j) of the proposed AD, and figure 8 to paragraph (k) of the proposed 
AD be revised to allow the use of either the ``VALVE'' light that is 
integral to the crossfeed valve switch, or the associated engine 
indication and crew alerting system (EICAS) message for the preflight 
operational check. UAL stated that if the ``VALVE'' light is 
inoperative, it would be unable to perform the check. UAL noted that 
MMEL relief is provided for the crossfeed valve lights.
    The FAA does not agree with the commenter's request to perform the 
check using the ``FWD/AFT FUEL CROSSFEED'' EICAS message because there 
are certain crossfeed valve actuator failure modes that can cause the 
crossfeed valve to remain closed without the ``FWD/AFT FUEL CROSSFEED'' 
EICAS message being displayed. Short of directly observing the valve 
actuator, monitoring the VALVE light to verify that the crossfeed valve 
actually transitioned from closed to open is the only way to verify 
from the flight deck that the crossfeed valve transitioned to the open 
position. While MMEL relief is provided for the VALVE light, that 
relief is subject to the provision that the crossfeed valve is verified 
to operate correctly.
    The FAA does agree to allow an alternative procedure that is 
effective if the ``VALVE'' light is inoperative, because it is possible 
to perform an operational check of the crossfeed valve by directly 
observing the movement of the actuator if the ``VALVE'' light is 
inoperative. The FAA has revised the referenced figures in this AD 
accordingly.

Request To Revise Crossfeed Valve Operational Check

    The Air Line Pilots Association, International (ALPA), Allied 
Pilots Association (APA), and Captain Stewart asked for revisions to 
the operational checks specified in the proposed AD. Captain Stewart 
asked that certain crossfeed valve actions in the proposed AD be 
changed to require one of the following: (1) Performing the crossfeed 
valve operational check in flight, prior to entering the ETOPS segment 
of the flight, and diverting the airplane to a suitable airport if the 
check fails, or (2) opening the crossfeed valve prior to entry into the 
ETOPS segment, leaving the crossfeed valve open throughout the ETOPS 
segment, and diverting the airplane to a suitable airport if the valve 
fails to open. Captain Stewart pointed out that operation with the 
crossfeed valve open for the duration of the ETOPS portion of the 
flight was proven effective at a major airline.
    ALPA, while supporting the inclusion of an operational check prior 
to dispatch of ETOPS flights, stated that since the action in the 
proposed AD is not directed at a specific crossfeed valve failure mode, 
and is instead intended to identify and minimize the exposure to any 
crossfeed valve failure mode, it is important to check the crossfeed 
valve in its normal operating environment during flight. ALPA therefore 
requested that the proposed AD be revised to include an AFM requirement 
for airplanes with only one crossfeed valve, and a MEL requirement for 
airplanes with two crossfeed valves, for an operational check of the 
crossfeed valve during cruise, prior to the entering ETOPS airspace.
    APA had no objection to the steps for checking the crossfeed valve 
operation, using the procedure recommended by the original equipment 
manufacturer (OEM). APA recommended checking the crossfeed valve 
immediately prior to the ETOPS segment of the flight where its 
operation has the potential to be critical.
    The FAA does not agree with the commenters' requests. Although the 
agency agrees that operationally checking the crossfeed valve 
immediately prior to entering the critical ETOPS portion of each ETOPS 
flight would provide a greater reduction in the risk that a crossfeed 
valve will fail to open in the fuel-critical phase of flight should an 
engine failure occur, it would also significantly increase the costs 
associated with each discovered failure of a crossfeed valve. The cost 
of an air turn-back or diversion is significantly higher than the cost 
of a delay for maintenance, and is likely to be greater than the cost 
of a flight cancellation. The FAA considered the additional costs that 
would be incurred by operators from an air turn-back or diversion each 
time a crossfeed valve fails its check, and also considered the 
additional reduction in exposure to latent crossfeed valve failures 
that develop between the time of a preflight check and the time of an 
ETOPS entry check. As a result of these considerations, the FAA 
determined that the incremental reduction in exposure to the 
development of a latent crossfeed valve failure due to checking the 
crossfeed valve in-flight prior to entry into the critical ETOPS 
portion of the flight, when the low probability of an engine failure is 
also considered, did not justify imposing those significant additional 
operational costs and service disruptions on affected operators.
    Before the NPRM was published, the FAA discussed with Boeing the 
value of conducting the crossfeed valve operational check during flight 
under cold soak conditions (which are part of the normal operating 
environment), versus performing the check on the ground. As a result of 
some of the comments on the NPRM, the agency discussed this issue again 
with Boeing, and placed a record of that discussion

[[Page 67842]]

in the public rulemaking docket. Boeing stated that the valve actuator 
failure modes identified by other commenters that result in actuator 
failures only in cold soak conditions have been corrected in newer 
designs. Boeing further stated that the previous valve actuator 
configurations that had those issues are no longer in service. Boeing 
added that it had no reason to believe that a check of the current in-
service crossfeed valves under cold, in-flight conditions would detect 
failures that would not be detected on the ground.
    In addition, the FAA does not agree with the request to require 
operation with the crossfeed valve open throughout the ETOPS segment of 
flight. While operation in that configuration would prevent the need to 
open the crossfeed valve in the event of an engine failure, there are 
other failure scenarios (such as a large fuel leak or contamination of 
one main tank) where operating with the crossfeed valve open 
compromises the intended isolation and independence of the fuel system 
for each engine. Also, differences in fuel pump performance could cause 
the need for repeated switching off and on of fuel pumps to maintain 
balanced main tanks. The FAA considers this undesirable because a 
flight crew error could put one or both engines on suction feed, 
potentially causing engine flameout. It would also add start/stop 
cycles on the fuel pumps, which could cause additional pump failures. 
Such a procedure is not recommended or approved by either Boeing or the 
FAA. Finally, that procedure violates the required fuel usage 
procedures in the limitations section of the FAA-approved AFMs for all 
of the affected airplane models, which require the airplane to be 
operated with the crossfeed valve closed except when it is specifically 
required to be open for crossfeeding to maintain balanced main tanks or 
for a low fuel condition. Therefore, that procedure would also violate 
14 CFR 91.9, which requires operators to operate aircraft in accordance 
with their applicable AFM limitations, unless a revised AFM was 
approved. In light of all these factors, the AD has not been changed in 
this regard.

Request To Change MMEL-Related Requirements

    Captain Stewart recommended that the proposed AD be revised to 
require an MMEL revision with clearly written provisions that identify 
the appropriate verification to confirm that no latent faults exist. 
Captain Stewart added that there is no benefit in mandating specific 
(M) & (O) procedures in the proposed AD, because it would cause an 
unnecessary administrative burden. Captain Stewart concluded that MELs 
published without the adequate (M) & (O) procedures indicates a failure 
of the MEL review/approval process at the flight standards district 
office (FSDO) or certificate management office (CMO) level.
    The FAA infers that the commenter is requesting that the MEL 
entries for operation with an inoperative crossfeed valve or fuel 
balancing system (for Model 787 airplanes) state the requirement for 
and objectives of the MEL maintenance and operational requirements, 
rather than mandating specific maintenance or operational procedures. 
The FAA does not agree with the commenter's request. In this case, 
there are various ways that the operational or maintenance check can be 
done, some of which would not detect all of the possible crossfeed 
valve failure modes. Therefore, the FAA has determined that the agency 
should maintain control over the operational and maintenance check 
procedures used. Operators may, however, apply for an AMOC in 
accordance with paragraph (o) of this AD, provided they can show that 
their proposed alternative operational or maintenance procedures 
adequately address the unsafe condition. The AD has not been changed in 
this regard.

Request To Exempt Certain Airplanes

    FedEx asked that the proposed AD be revised to exclude airplanes 
that are not used for ETOPS operations from the proposed requirement to 
revise the existing AFM and MEL. Specifically, FedEx requested that 
paragraphs (h), (i), (j), and (k) of the proposed AD be revised to add 
``Airplanes that are not used for ETOPS operations are exempt from the 
requirements of this paragraph.'' FedEx stated that the proposed AD 
does not allow for exemption of affected fleets that are not certified 
or utilized for ETOPS operations. FedEx reported that its fleets 
include the types of airplanes affected by the proposed AD, but that 
only its Model 777F airplanes are certified for ETOPS operations.
    The FAA does not agree with the commenter's request. The addition 
of the language proposed by the commenter is not sufficient to ensure 
that the existing AFM and MEL will be updated as required by this AD if 
there is an operational change in the future. However, operators may 
apply for an AMOC in accordance with paragraph (o) of this AD, provided 
they submit a proposal that (1) describes how the operator will ensure 
that future introduction of ETOPS operations includes the required AFM 
and MEL changes and (2) is supported by its FAA POI. The AD has not 
been changed in this regard.

Request To Clarify Instructions for Operational Check

    FedEx and Japan Airlines (JAL) asked that the language in figure 8 
to paragraph (k) of the proposed AD be revised to include instructions 
for a fuel crossfeed valve operational check including ``steps on the 
ground prior to engine start.'' The commenters requested that ``prior 
to engine start'' be changed to ``prior to each flight.'' FedEx stated 
that this language should be clarified given that the intent of the 
proposed AD is to prevent fuel in the main tank associated with the 
failed engine from being unavailable to the remaining operative engine, 
potentially resulting in a forced off-airport landing. JAL stated that 
the time for performing the operational check in the proposed AD is 
more restrictive than that in the MMEL. JAL added that since both are 
the same action, that compliance time should be the same.
    The FAA acknowledges the commenters' concerns regarding potential 
misunderstanding of when to perform the operational check, and agree 
that clarification is necessary. The FAA infers that FedEx found that 
figure 8 to paragraph (k) of this AD was not sufficiently clear that 
the operational check is intended to be performed prior to each flight. 
The FAA presumes that FedEx's concern is that an operator might perform 
the operational check only once prior to the first engine start after 
placing the other inoperative crossfeed valve on MEL relief, but not 
prior to subsequent flights on the MEL. The intent of the procedure is 
that an operational check of the crossfeed valve be performed, by 
maintenance personnel or flightcrew, immediately prior to each ETOPS 
flight, as was stated in the ``Proposed AD Requirements'' section of 
the NPRM.
    The FAA disagrees with using the specific language proposed by 
FedEx because its language would not alleviate the confusion about the 
intent of the requirement, and might be interpreted as allowing the 
check to be performed at any time prior to flight, as opposed to 
immediately prior to each flight. Although the comment from FedEx 
requested a change to figure 8 to paragraph (k) of this AD, which 
provides the required MEL revision for the Model 767, the FAA is 
satisfied that the MEL language in figure 7 to paragraph (j) of this 
AD, figure 8 to paragraph (k) of this AD, figure 9 to paragraph (l) of 
this AD, and figure 10

[[Page 67843]]

to paragraph (m) of this AD is clear with respect to the intended 
timing of performing the crossfeed valve operational check.
    The general intent of operational procedures in the existing MEL is 
that they are associated with each flight conducted with the 
inoperative equipment. However, the comments provided caused the agency 
to reconsider whether the corresponding language in the AFM revisions 
required for airplanes equipped with single crossfeed valves are 
sufficiently clear regarding the intended timing for the check. In 
light of this, figure 1 to paragraph (g)(1) of this AD, figure 3 to 
paragraph (h)(1) of this AD, and figure 5 to paragraph (i)(1) of this 
AD of this AD have been revised to clarify the AFM limitations on 
airplanes equipped with a single crossfeed valve. However, the language 
in other figures, including figure 8 to paragraph (k) of this AD, have 
not been changed.

Request To Change Time for Performing Operational Check

    DAL asked that the time for performing the operational check be 
changed to the last hour of the cruise flight, instead of prior to each 
ETOPS flight. DAL stated that solder joint cracks at the connectors and 
electronic assembly could cause intermittent or hard fault failure of 
the motor-operated crossfeed valves (MOVs) that is difficult to detect 
during the ground test prior to each ETOPS flight. DAL added that a 
cold soak test at the end of the cruise flight will better detect 
intermittent MOV failures than a test performed on the ground.
    The FAA does not agree with the commenter's request. At the FAA's 
request, Boeing examined the commenter's statements, and Boeing 
provided comments. A record of the phone conversation in which Boeing 
provided its comments was placed in the public rulemaking docket for 
this AD. Boeing stated that the valve actuator failure modes described 
by DAL that tended to occur in cold conditions were successfully 
addressed by design improvements, and that the valve actuator 
configurations that were susceptible to failures that could only be 
detected in cold conditions have been replaced on operational aircraft 
and are no longer in service. Boeing added that its more recent failure 
data shows that the timing of failures is random, and that the ability 
to detect a failed crossfeed valve is no longer significantly impacted 
by environmental conditions during the operational check.
    As previously discussed, the FAA has determined that the greatest 
practical reduction in risk during operation with a single operational 
crossfeed valve would be achieved by requiring the operational check as 
close as possible to the beginning of the fuel-critical ETOPS portion 
of the flight. However, as noted, the impact of requiring the 
operational check in flight, just prior to entry into the ETOPS portion 
of the flight, would cause a significant number of air turn-backs and 
diversions at significant cost, so the FAA, with agreement from Boeing, 
proposed the check requirement for immediately prior to each ETOPS 
flight. Therefore, this AD has not been changed in this regard.

Request To Reduce Compliance Time

    ALPA asked that the compliance time be reduced from 120 to 90 days. 
ALPA stated that the proposed AD would not require extensive, one-time 
maintenance actions on affected airplanes, but only revision of 
existing AFM and MEL actions, thus the commenter recommended a shorter 
compliance time.
    The FAA does not agree with the commenter's request. In conjunction 
with Boeing, the FAA has determined that the compliance time for each 
airplane model will accommodate the time necessary to accomplish the 
actions required by this AD and maintain an adequate level of safety. 
In addition, the suggested compliance time change would alter the 
requirements of this AD, so additional rulemaking would be required, 
ultimately delaying issuance of the AD. The FAA finds that delaying 
this action further is inappropriate in light of the identified unsafe 
condition. However, if additional data are presented that would justify 
a shorter compliance time, the FAA may consider further rulemaking on 
this issue. The AD has not been changed in this regard.

Request To Add Airplanes to Applicability

    American Airlines asked that Model 737-7, -8, and -9 (MAX) 
airplanes be added to the applicability of the proposed AD. American 
Airlines stated that the design on these airplanes is similar to that 
of the Model 737 Classic and Next Gen airplanes.
    The FAA does not agree with the request. Although the commenter is 
correct about the similar design, this unsafe condition was identified 
at the time of certification of the 737 MAX airplanes as a planned 
airworthiness directive against the existing Model 737 airplanes. 
Therefore, Boeing included the requirement for the operational check of 
the crossfeed valve required by this AD in the FAA-approved AFM for the 
737 MAX airplanes. The AD has not been changed in this regard.

Engineering Oversight

    Captain Stewart and APA stated that it is an engineering oversight 
that new production ETOPS airplanes are being certificated with only 
one fuel crossfeed valve installed.
    The FAA acknowledges the commenter's concern about the risk 
associated with two-engine ETOPS airplanes that depend on a single 
active component to allow the remaining engine to access all of the 
remaining fuel on board after an engine failure. However, the allowance 
for such designs was not an engineering oversight, but a result of how 
the initial 120-minute ETOPS type-design standards were developed with 
existing airplanes in mind, of the later 180-minute ETOPS type-design 
standards being developed based on the 120-minute standards, and of 
conscious decision making by Boeing and the FAA associated with AD 88-
21-03 R1 (which applies to certain Airbus Model A300 and A310-200 
series airplanes, and Boeing Model 737-200, 737-300, 757-200, 767-200, 
and 767-300 series airplanes) and certification of the Model 737-700 
airplane. Discussion of the potential need for improvements to 
airworthiness standards is outside the scope of the actions required by 
this AD. Therefore, the AD has not been changed in this regard.

Report of Incident

    Commenter Amirul Ismail provided what appears to be a pilot report 
of an instance where an operational check of the crossfeed valve on a 
Model 737-800 airplane resulted in the VALVE light failing to 
extinguish. The incident appears to be an indication-related fault 
rather than a valve actuator failure. No change to the final rule has 
been made.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule with the changes described previously 
and minor editorial changes. The FAA has determined that these minor 
changes:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

[[Page 67844]]

Costs of Compliance

    The FAA estimates that this AD affects 3,252 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts  cost       product        operators
----------------------------------------------------------------------------------------------------------------
AFM Revision (2,127 airplanes)........  1 work-hour x $85 per                 $0             $85        $180,795
                                         hour = $85.
MEL Revision (1,125 airplanes)........  1 work-hour x $85 per                  0              85          95,625
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, part A, subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to transport category airplanes and 
associated appliances to the Director of the System Oversight Division.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2019-19-10 The Boeing Company: Amendment 39-19746; Docket No. FAA-
2017-1024; Product Identifier 2017-NM-065-AD.

(a) Effective Date

    This AD is effective January 16, 2020.

(b) Affected ADs

    This AD affects AD 88-21-03 R1, Amendment 39-6077 (53 FR 46605, 
November 18, 1988) (``AD 88-21-03 R1'').

(c) Applicability

    This AD applies to all The Boeing Company airplanes, 
certificated in any category, identified in paragraphs (c)(1) 
through (5) of this AD.
    (1) Model 737-300, -400, -500, -600, -700, -700C, -800, -900, 
and -900ER series airplanes.
    (2) Model 757-200, -200PF, -200CB, and -300 series airplanes.
    (3) Model 767-200, -300, -300F, and -400ER series airplanes.
    (4) Model 777-200, -200LR, -300, -300ER, and -777F series 
airplanes.
    (5) Model 787-8 and 787-9 airplanes.

(d) Subject

    Air Transport Association (ATA) of America Code 28; Fuel.

(e) Unsafe Condition

    This AD was prompted by reports of fuel crossfeed valves failing 
to open when activated during flight. The FAA is issuing this AD to 
prevent an airplane from being dispatched on an extended operations 
(ETOPS) flight with a single fuel crossfeed valve (due to design or 
due to minimum equipment list (MEL) dispatch of a dual crossfeed 
valve equipped airplane with one crossfeed valve inoperative) that 
cannot be opened or a fuel balancing system that cannot properly 
operate when activated. This condition could cause the fuel in the 
main tank associated with a failed engine to be unavailable to the 
remaining operative engine, potentially resulting in a forced off 
airport landing due to exhaustion of the remaining usable fuel and 
consequent loss of all engine thrust.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) AFM Revisions for Model 737 Airplanes Equipped With a Single Fuel 
Crossfeed Valve

    For airplanes identified in paragraph (c)(1) of this AD: Within 
120 days after the effective date of this AD, do the actions 
specified in paragraphs (g)(1) and (2) of this AD.
    (1) Revise the ``Extended Range Operations'' subsection of the 
``Fuel System Limitations'' section of the Section 1 Certificate 
Limitations of the existing airplane flight manual (AFM) by 
incorporating the information specified in figure 1 to paragraph 
(g)(1) of this AD. This may be done by inserting a copy of this AD 
into the existing AFM. When a statement identical to that in figure 
1 to paragraph (g)(1) of this AD has been included in the ``Extended 
Range Operations'' subsection of the ``Fuel System Limitations'' 
section of the Section 1 Certificate Limitations of the general 
revisions of the existing AFM, the general revisions may be inserted 
into the existing AFM, and the copy of this AD may be removed from 
the existing AFM.

[[Page 67845]]

[GRAPHIC] [TIFF OMITTED] TR12DE19.000

    (2) Revise the ``Extended Range Operations'' section of the 
Section 3 Normal Procedures of the existing AFM by incorporating the 
information specified in figure 2 to paragraph (g)(2) of this AD. 
This may be done by inserting a copy of this AD into the existing 
AFM. When a statement identical to that in figure 2 to paragraph 
(g)(2) of this AD has been included in the ``Extended Range 
Operations'' section of Section 3 Normal Procedures of the existing 
AFM, the general revisions may be inserted into the existing AFM, 
and the copy of this AD may be removed from the existing AFM.
[GRAPHIC] [TIFF OMITTED] TR12DE19.001

(h) AFM Revisions for Model 757 Airplanes Equipped With a Single Fuel 
Crossfeed Valve

    For airplanes identified in paragraph (c)(2) of this AD having 
line numbers 1 through 518 inclusive, on which the actions specified 
in Boeing Service Bulletin 757-28-0029 (second fuel crossfeed valve 
installation) have not been done: Within 120 days after the 
effective date of this AD, do the actions specified in paragraphs 
(h)(1) and (2) of this AD. For Model 757 airplanes identified in 
this paragraph, if the actions specified in Boeing Service Bulletin 
757-28-0029 have been done, the actions specified in this paragraph 
are no longer required for that airplane and the actions specified 
in paragraph (j) of this AD must be done before further flight after 
the actions specified in Boeing Service Bulletin 757-28-0029 have 
been performed.
    (1) Revise the ``Extended Range Operations'' section of the 
Section 1 Certificate Limitations of the existing AFM by 
incorporating the information specified in figure 3 to paragraph 
(h)(1). This may be done by inserting a copy of this AD into the 
existing AFM. When a statement identical to that in figure 3 to 
paragraph (h)(1) of this AD has been included in the ``Extended 
Range Operations'' section of the Section 1 Certificate Limitations 
of the general revisions of the existing AFM, the general revisions 
may be inserted into the existing AFM, and the copy of this AD may 
be removed from the existing AFM.

[[Page 67846]]

[GRAPHIC] [TIFF OMITTED] TR12DE19.002

    (2) Revise the ``Extended Range Operations'' section of Section 
3 Normal Procedures of the existing AFM by incorporating the 
information specified in figure 4 to paragraph (h)(2) of this AD. 
This may be done by inserting a copy of this AD into the existing 
AFM. When a statement identical to that in figure 4 to paragraph 
(h)(2) of this AD has been included in the ``Extended Range 
Operations'' section of Section 3 Normal Procedures of the existing 
AFM, the general revisions may be inserted into the existing AFM, 
and the copy of this AD may be removed from the existing AFM.
[GRAPHIC] [TIFF OMITTED] TR12DE19.003

(i) AFM Revisions for Model 767 Airplanes Equipped With a Single Fuel 
Crossfeed Valve

    For airplanes identified in paragraph (c)(3) of this AD having 
line numbers 1 through 430 inclusive on which the actions specified 
in Boeing Service Bulletin 767-28-0034 (second fuel crossfeed valve 
installation) have not been done as of the effective date of this 
AD: Within 120 days after the effective date of this AD, do the 
actions specified in paragraphs (i)(1) and (2) of this AD. For 
airplanes on which the actions specified in Boeing Service Bulletin 
767-28-0034 have been done, the actions specified in this paragraph 
are no longer required for that airplane and the actions specified 
in paragraph (k) of this AD must be done before further flight.
    (1) Revise the ``Extended Range Operations'' section of the 
Section 1 Certificate Limitations of the existing AFM by 
incorporating the information specified in figure 5 to paragraph 
(i)(1) of this AD. This may be done by inserting a copy of this AD 
into the existing AFM. When a statement identical to that in figure 
5 to paragraph (i)(1) of this AD has been included in the ``Extended 
Range Operations'' section of the Section 1 Certificate Limitations 
of the general revisions of the existing AFM, the general revisions 
may be inserted into the existing AFM, and the copy of this AD may 
be removed from the existing AFM.

[[Page 67847]]

[GRAPHIC] [TIFF OMITTED] TR12DE19.004

    (2) Revise the ``Extended Range Operations'' section of Section 
3.1 Normal Procedures of the existing AFM by incorporating the 
information specified in figure 6 to paragraph (i)(2) of this AD. 
This may be done by inserting a copy of this AD into the existing 
AFM. When a statement identical to that in figure 6 to paragraph 
(i)(2) of this AD has been included in the ``Extended Range 
Operations'' section of Section 3.1 Normal Procedures of the 
existing AFM, the general revisions may be inserted into the 
existing AFM, and the copy of this AD may be removed from the 
existing AFM.
[GRAPHIC] [TIFF OMITTED] TR12DE19.005

(j) MEL Revisions for Model 757 Airplanes Equipped With Dual Fuel 
Crossfeed Valves

    For airplanes identified in paragraph (c)(2) of this AD having 
line numbers 519 and subsequent; and for airplanes identified in 
paragraph (c)(2) of this AD having line numbers 1 through 518 
inclusive, on which a second fuel crossfeed valve has been 
installed, as specified in Boeing Service Bulletin 757-28-0029: 
Within 120 days after the effective date of this AD, revise the 
operator's existing FAA-approved MEL by incorporating the 
information specified in figure 7 to paragraph (j) of this AD as a 
required operations procedure when dispatching for ETOPS operation 
with an inoperative fuel crossfeed valve. Specific alternative MEL 
wording to accomplish the actions specified in figure 7 to paragraph 
(j) of this AD can be approved by the operator's principal 
operations inspector (POI).

[[Page 67848]]

[GRAPHIC] [TIFF OMITTED] TR12DE19.006

(k) MEL Revisions for Model 767 Airplanes Equipped With Dual Fuel 
Crossfeed Valves

    For airplanes identified in paragraph (c)(3) of this AD having 
line numbers 431 and subsequent; and for airplanes identified in 
paragraph (c)(3) of this AD having line numbers 1 through 430 
inclusive on which a second fuel crossfeed valve has been installed, 
as specified in Boeing Service Bulletin 767-28-0034: Within 120 days 
after the effective date of this AD, revise the operator's existing 
FAA-approved MEL by incorporating the information specified in 
figure 8 to paragraph (k) of this AD as a required operations 
procedure when dispatching for ETOPS operation with an inoperative 
fuel crossfeed valve. Specific alternative MEL wording to accomplish 
the actions specified in figure 8 to paragraph (k) of this AD can be 
approved by the operator's POI.
[GRAPHIC] [TIFF OMITTED] TR12DE19.007

(l) MEL Revisions for Model 777 Airplanes

    For airplanes identified in paragraph (c)(4) of this AD: Within 
120 days after the effective date of this AD, revise the operator's 
existing FAA-approved MEL by incorporating the information specified 
in figure 9 to paragraph (l) of this AD as a required operations 
procedure when dispatching for ETOPS operation with an inoperative 
fuel crossfeed valve. Specific alternative MEL wording to accomplish 
the actions specified in figure 9 to paragraph (l) of this AD can be 
approved by the operator's POI.

[[Page 67849]]

[GRAPHIC] [TIFF OMITTED] TR12DE19.008

(m) MEL Revisions for Model 787 Airplanes

    For airplanes identified in paragraph (c)(5) of this AD: Within 
120 days after the effective date of this AD, revise the operator's 
existing FAA-approved MEL by incorporating the information specified 
in figure 10 to paragraph (m) of this AD into the MEL requirements 
for each of the inoperative items specified in paragraphs (m)(1) 
through (4) of this AD. Specific alternative MEL wording to 
accomplish the actions specified in figure 10 to paragraph (m) of 
this AD can be approved by the operator's POI.
    (1) 28-21-01-01 Pressure Refueling System, Main Tank Inboard 
Refuel Valve.
    (2) 28-22-06 Fuel Balance Switch.
    (3) 28-26-01 Defuel/Isolation Valves.
    (4) 28-41-01-01 Main Tank Fuel Quantity Indication Systems.

[[Page 67850]]

[GRAPHIC] [TIFF OMITTED] TR12DE19.009

(n) AD 88-21-03 R1 AFM Limitation Removal

    After the applicable AFM limitations specified in paragraphs 
(g)(1), (h)(1), and (i)(1) of this AD are incorporated into an 
airplane's existing AFM, operators may remove the AFM limitation 
required by AD 88-21-03 R1, for that airplane.

(o) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (p) of this AD. Information may be 
emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Seattle 
ACO Branch, FAA, to make those findings. To be approved, the repair 
method, modification deviation, or alteration deviation must meet 
the certification basis of the airplane, and the approval must 
specifically refer to this AD.

(p) Related Information

    For more information about this AD, contact Jon Regimbal, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3557; email: [email protected].

[[Page 67851]]

(q) Material Incorporated by Reference

    None.

    Issued in Des Moines, Washington, on October 3, 2019.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-26736 Filed 12-11-19; 8:45 am]
BILLING CODE 4910-13-P