Airworthiness Directives; Pratt & Whitney Models PW2037, PW2037(M), and PW2040 Turbofan Engines, 22426-22429 [E9-10953]

Download as PDF 22426 Federal Register / Vol. 74, No. 91 / Wednesday, May 13, 2009 / Rules and Regulations Management, P.O. Box 3707, MC 2H–65, Seattle, Washington 98124–2207; telephone 206–544–5000, extension 1; fax 206–766– 5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. (3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425–227–1221 or 425–227–1152. (4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/ code_of_federal_regulations/ ibr_locations.html. Federal Aviation Administration DATES: This AD becomes effective June 17, 2009. ADDRESSES: You can get the service information identified in this AD from Pratt & Whitney, 400 Main Street, East Hartford, CT 06108. The Docket Operations office is located at Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue SE., West Building Ground Floor, Room W12–140, Washington, DC 20590–0001. FOR FURTHER INFORMATION CONTACT: Mark Riley, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: mark.riley@faa.gov; telephone (781) 238–7758, fax (781) 238–7199. SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to PW models PW2037, PW2037(M), and PW2040 turbofan engines. We published the proposed AD in the Federal Register on November 14, 2008 (73 FR 67427). That action proposed to require inspecting all HPT 2nd stage hubs at the next HPT overhaul after the effective date of the AD. 14 CFR Part 39 Examining the AD Docket Issued in Renton, Washington, on May 1, 2009. Stephen P. Boyd, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. E9–10935 Filed 5–12–09; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION [Docket No. FAA–2008–1131; Directorate Identifier 2008–NE–37–AD; Amendment 39– 15903; AD 2009–10–08] RIN 2120–AA64 Airworthiness Directives; Pratt & Whitney Models PW2037, PW2037(M), and PW2040 Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: The FAA is adopting a new airworthiness directive (AD) for Pratt & Whitney models PW2037, PW2037(M), and PW2040 turbofan engines with high-pressure turbine (HPT) 2nd stage hubs that have previously been exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 or equivalent procedure. This AD requires a onetime optical comparator inspection (OCI) of the blade retention slots of the affected HPT 2nd stage hubs at the next HPT overhaul after the effective date of the AD. This AD results from an uncontained release of HPT 2nd stage blades and blade retention lugs. We are issuing this AD to remove nonconforming HPT 2nd stage hubs, which could result in an uncontained release of turbine blades and blade retention lugs, and damage to the airplane. VerDate Nov<24>2008 17:32 May 12, 2009 Jkt 217001 You may examine the AD docket on the Internet at http:// www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647–5527) is provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt. Comments We provided the public the opportunity to participate in the development of this AD. We have considered the comments received. Recommend Referring to the Inspection as ‘‘Special Dimensional Inspection’’ Pratt & Whitney recommends that the inspection in the proposed AD be referred to as a ‘‘Special Dimensional Inspection’’ per Pratt & Whitney Alert Service Bulletin (ASB) PW2000 72–734, which is approved by the FAA. The proposed AD currently specifies an Optical Comparator Inspection (OCI). Use of the term ‘‘Special Dimensional Inspection’’ instead of OCI will provide better alignment with the inspection procedures that Pratt & Whitney is presently developing and for which it PO 00000 Frm 00006 Fmt 4700 Sfmt 4700 will seek FAA approval, to use as an alternative to OCI. We do not agree. The inspection is an OCI. Therefore, identifying the type of inspection the AD requires by its name is proper. We did not change the AD. Request To Revise the Estimated Cost Pratt & Whitney and two air carriers request that we revise the estimated cost to perform an OCI. Pratt & Whitney states that the cost is higher than previously anticipated and we should add about $4,000 to the cost of each disk overhaul. Delta Air Lines states that the total cost is actually closer to $8,000 and it should include shipping ($1,000), vendor charges ($5,900), and should take into account additional inventory required ($180,000 per hub) due to outof-service time required to support the off-site inspection. We partially agree. We agree that the cost estimate in the proposed AD is not accurate. We do not agree that it should consider shipping charges or additional inventory requirements unique to each operator. We changed the cost to perform the OCI to $4,000 for each HPT stage 2 hub as quoted by Pratt & Whitney and updated the total to $3,048,000. Request for Clarification of the Inspection Being a Onetime Inspection Pratt & Whitney and two air carriers request clarification in the AD to state that the inspection is a onetime inspection. Also, Delta Air Lines comments that repetitive inspections should be required unless the cause of the hub out-of-tolerance condition is addressed. They also stated that the cause of the hub out-of-tolerance condition is not known and repetitive inspections are therefore required. We partially agree. We agree that we need to clarify that the OCI is a onetime inspection requirement. We changed the AD to clarify that the OCI is a onetime inspection requirement. We do not agree that the AD should require repetitive inspections. If we determine at a later date that repetitive inspections are required, we may issue an AD to require them. Proposal To Eliminate the Fluorescent Penetrant Inspection Pratt & Whitney and United Airlines propose that we eliminate the fluorescent penetrant inspection (FPI) requirement for the HPT 2nd stage hub. FPI of the HPT 2nd stage hub is redundant, since it is already mandated per FAA AD 2005–18–03. We agree. We changed the AD to only require a onetime OCI of the HPT 2nd stage hub after the fluorescent penetrant E:\FR\FM\13MYR1.SGM 13MYR1 Federal Register / Vol. 74, No. 91 / Wednesday, May 13, 2009 / Rules and Regulations inspection and all shop cleaning processes have been completed. Proposal To Reduce the Affected Population of HPT 2nd Stage Hubs Pratt & Whitney proposes that we reduce the affected population of HPT 2nd stage hubs to only those that have been exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 (cleaning processes that have similar abrasive characteristics) during their shop overhaul history. Based on recent findings from the NTSB-led investigation, the blade slot dimensional variations on the event hub and on other inspected hubs resulted from a specific process used during the cleaning of hubs during the normal overhaul process. We agree. We changed the AD applicability to state that this AD applies to Pratt & Whitney models PW2037, PW2037(M), and PW2040 turbofan engines with HPT 2nd stage hubs that have previously been exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 or equivalent procedure. Proposal To Delay Issuance of AD United Airlines proposes that we delay issuance of the AD, because initial OCI results are showing a 25% reject rate. This suggests that the proposed inspections will not detect the problem that led to the one industry failure. Otherwise, the industry failure rate would be higher. Consequently, issuing the AD would be premature, as the failure mechanism is not understood, and it is not clear that the proposed inspections will prevent future failures. We do not agree. The investigation identified that an out-of-tolerance condition of the HPT 2nd stage hub blade slots is the cause of the failure event. However, the root cause of the out-of-tolerance condition is still under investigation, but is believed to have been caused by aggressive cleaning with an abrasive media blast. Inspection of the HPT 2nd stage hub blade slots is required to identify hubs that are out-oftolerance, to minimize the risk of future failures. Pratt & Whitney is reviewing the current acceptance criteria for the OCI of HPT 2nd stage hub blade slots, and if appropriate, may revise these limits to reduce the current reject rate. We did not change the AD. Proposal To Remove the Reporting Requirement From the AD Three air carriers propose that we remove the requirement for operators to be responsible for reporting HPT 2nd stage hub OCI results within 72 hours of the inspection. Delta Air Lines also asks VerDate Nov<24>2008 17:32 May 12, 2009 Jkt 217001 if they are required to report OCI results after the 6-month period, since not all of their HPT 2nd stage hubs will go through overhaul within 6 months. The three air carriers state that it will be extremely difficult for operators to comply with the reporting requirements of the proposed rule, because it will not be the operators performing the inspections. The sole source that performs the inspections, (Pratt & Whitney), should be responsible for reporting to the FAA. We agree. We removed the reporting requirement from the AD. Request That an Alternate Inspection Be Developed That Is Not SourceApproved Two air carriers request that an alternate inspection method be developed that is not source-approved and will permit all overhaul shops the capability to perform the inspection. They state that Pratt & Whitney is currently the only source-approved vendor for the OCI. Operators are experiencing turn times in excess of 30 days, which is a hardship to them. We agree that an alternate inspection procedure that can be performed by all overhaul facilities is preferred. However, we are unaware of any that may exist. We will evaluate any proposed alternative inspection an operator may submit as an alternative method of compliance. We did not change the AD. Compliance Time Should Be Revised The National Transportation Safety Board (NTSB), states that the compliance time should be revised to reflect the recommended compliance time in the NTSB Urgent Safety Recommendation A–08–85. That compliance time requires removal of all PW2037 2nd stage turbine hubs for inspection when they have accumulated significantly fewer hours and/or cycles than the incident engine (10,880 hours and/or 4,392 cycles). The 10,880 hours and 4,392 cycles referenced in A–08–85 were based on the time and cycles that the incident engine had accumulated from the last overhaul until engine failure. Metallurgical examination of the failed hub was not able to discern any fatigue striations, so it is unknown how long it took those fatigue cracks to progress to failure. Typically, when the cause of the failure, or length of time for a crack to progress to failure is unknown, the time and/or cycles, whichever is less, since the part was new or overhauled until failure, is divided by a factor of two or three to establish a compliance schedule. PO 00000 Frm 00007 Fmt 4700 Sfmt 4700 22427 We do not agree. The field management plan defined in the proposed AD is based on a risk analysis performed by Pratt &Whitney, which we reviewed and concluded is adequate. Further, additional field data received to-date has not indicated any increased risk, or that a more restrictive field plan is required. We did not change the AD. Proposed OCI Procedure Should Be Revised The NTSB states that the proposed OCI procedure should be revised to also require that the blade slots be measured using a coordinate measuring machine (CMM) or another dimensional inspection device capable of measuring deviations in the center of the blade slots. The OCI procedure is limited to only measure the blade slot profile on the forward and aft ends of the blade slot. The current procedure does not measure the center portion of the blade slot. We partially agree. We agree that the current OCI procedure is limited such that it cannot measure the center portion of the blade slot. However, we disagree that the OCI procedure is not an acceptable inspection method to identify non-conforming hubs. We verified that the OCI procedure can identify HPT 2nd stage hubs with nonconforming blade retention slots. We established limits for OCI that ensured that no parts with non-conformances similar to the event hub would be released into service. We continue to work with Pratt & Whitney to identify other improved inspection methods that can be used as an alternate to OCI. We did not change the AD. AD Compliance Should Also Include Inspection of the HPT 2nd Stage Blade Root Serrations for Uneven Contact Wear The NTSB states that the AD compliance should also include inspection of the HPT 2nd stage blade root serrations for uneven contact wear, as defined in the PW2000 Engine Manual, Task 72–52–17–200–014, Inspection/Check 14. The AD should also specify an action to take with the HPT 2nd stage hubs if any HPT 2nd stage blades are detected with uneven wear. The HPT 2nd stage blades removed from the incident engine showed evidence of uneven contact wear on the blade root serrations. The AD should therefore also include inspection of the HPT 2nd stage blades and include an action to take with the hub if blades are detected to have root serrations with uneven wear. We do not agree. Inspection of the HPT 2nd stage blade root serrations was E:\FR\FM\13MYR1.SGM 13MYR1 22428 Federal Register / Vol. 74, No. 91 / Wednesday, May 13, 2009 / Rules and Regulations incorporated in the PW2000 Engine Manual to address a non-conformance issue for the blades and is performed during normal inspection. All blades that are identified with uneven wear on the root serrations are rejected and removed from service. The cause of failure of the incident engine was due to a nonconformance of the HPT 2nd stage hub blade retention slots. All HPT 2nd stage hubs that have previously been exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 or equivalent procedure will require OCI per the AD. All non-conforming hubs will be identified by OCI and removed from service. We did not change the AD. AD Should Mandate That All of the HPT 2nd Stage Hub Blade Slots Be Inspected Using OCI The NTSB states that the AD should mandate that all of the HPT 2nd stage hub blade slots be inspected using OCI. The current procedure only requires that every fourth blade retaining slot in the hub be inspected. The incident engine had cracks in several adjacent blade retaining lugs that resulted in the simultaneous release of multiple blades that exceeded the turbine case’s containment capability. If only every fourth slot in the hub is inspected, then two adjacent nonconforming blade slots could slip through the inspection and result in an uncontained engine failure. We do not agree. Inspecting every fourth blade retaining slot will identify all non-conforming hubs. HPT 2nd stage hubs that are aggressively cleaned using a grit blast procedure will typically have a high number of non-conforming slots. Field inspection data to-date indicates that this assumption currently remains valid. We did not change the AD. Conclusion We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. Costs of Compliance We estimate that this AD will affect 762 engines installed on airplanes of U.S. registry. We also estimate that it will take about 50 work-hours per engine to perform the actions, and that the average labor rate is $80 per workhour. No parts are required. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $3,048,000. VerDate Nov<24>2008 17:32 May 12, 2009 Jkt 217001 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. We are 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. Regulatory Findings We have determined that 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) Is not a ‘‘significant rule’’ under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 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. We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. Adoption of the Amendment Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration 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. PO 00000 Frm 00008 Fmt 4700 Sfmt 4700 § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: ■ 2009–10–08 Pratt & Whitney: Amendment 39–15903. Docket No. FAA–2008–1131; Directorate Identifier 2008–NE–37–AD. Effective Date (a) This airworthiness directive (AD) becomes effective June 17, 2009. Affected ADs (b) None. Applicability (c) This AD applies to Pratt & Whitney models PW2037, PW2037(M), and PW2040 turbofan engines with high-pressure turbine (HPT) 2nd stage hubs that have previously been exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 or equivalent procedure. These engines are installed on, but not limited to, Boeing 757–200 and 757– 300 airplanes. Unsafe Condition (d) This AD results from an uncontained release of HPT 2nd stage blades and blade retention lugs. We are issuing this AD to remove nonconforming HPT 2nd stage hubs, which could result in an uncontained release of turbine blades and blade retention lugs, and damage to the airplane. Compliance (e) You are responsible for having the actions required by this AD performed at the next HPT overhaul, unless the actions have already been done. Onetime Optical Comparator Inspection (OCI) of HPT 2nd Stage Hubs (f) Perform a onetime optical comparator inspection of the HPT 2nd stage hubs after a fluorescent penetrant inspection and all shop cleaning processes have been completed. Pratt & Whitney Alert Service Bulletin No. PW2000 A72–734, dated November 3, 2008, contains information about the optical comparator inspection. (g) Remove from service any hubs that fail the optical comparator inspection. Definition (h) This AD defines an HPT overhaul as when the HPT is at its piece-part level. Alternative Methods of Compliance (i) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19. Related Information (j) Contact Mark Riley, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: mark.riley@faa.gov; telephone (781) 238–7758, fax (781) 238–7199, for more information about this AD. (k) Pratt & Whitney Alert Service Bulletin No. PW2000 A72–734, dated November 3, 2008, contains information about the optical comparator inspection. E:\FR\FM\13MYR1.SGM 13MYR1 Federal Register / Vol. 74, No. 91 / Wednesday, May 13, 2009 / Rules and Regulations Material Incorporated by Reference (l) None. Issued in Burlington, Massachusetts, on May 4, 2009. Peter A. White, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. E9–10953 Filed 5–12–09; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2007–27747; Directorate Identifier 2007–CE–030–AD; Amendment 39–15904; AD 2009–10–09] RIN 2120–AA64 Airworthiness Directives; Cessna Aircraft Company 150 and 152 Series Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: The FAA is adopting a new airworthiness directive (AD) for Cessna Aircraft Company (Cessna) 150 and 152 series airplanes. This AD requires you to either install a placard prohibiting spins and other acrobatic maneuvers in the airplane or to replace the rudder stop, rudder stop bumper, and attachment hardware with a new rudder stop modification kit and replace the safety wire with jamnuts. This AD results from follow-on investigations of two accidents where the rudder was found in the over-travel position with the stop plate hooked over the stop bolt heads. While neither of the accident aircraft met type design, investigations revealed that aircraft in full conformity with type design can exceed the travel limits set by the rudder stops. We are issuing this AD to prevent the rudder from traveling past the normal travel limit. Operation in this non-certificated control position is unacceptable and could cause undesirable consequences, such as contact between the rudder and the elevator. DATES: This AD becomes effective on June 17, 2009. On June 17, 2009, the Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD. ADDRESSES: To get the service information identified in this AD, contact Cessna Aircraft Company, Product Support, P.O. Box 7706, Wichita, KS 67277; telephone: (316) VerDate Nov<24>2008 17:32 May 12, 2009 Jkt 217001 517–5800; fax: (316) 517–7271; Internet: http://www.cessna.com. To view the AD docket, go to U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., Washington, DC 20590, or on the Internet at http:// www.regulations.gov. The docket number is FAA–2007–27747; Directorate Identifier 2007–CE–030–AD. FOR FURTHER INFORMATION CONTACT: Ann Johnson, Aerospace Engineer, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, Kansas 67209; telephone: (316) 946– 4105; fax: (316) 946–4107. SUPPLEMENTARY INFORMATION: Discussion On April 10, 2007, we issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain Cessna Aircraft Company (Cessna) 150 and 152 series airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on April 16, 2007 (72 FR 18925). The NPRM proposed to require replacement of the rudder stop, rudder stop bumper, and attachment hardware with a new rudder stop modification kit and replacement of the safety wire with jamnuts. Comments We provided the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and FAA’s response to each comment: Comment Issue No. 1: SAIB Instead of NPRM Joseph Morales, Gary Iverson, Sr., Al Roesner, Gerald D. Clark, Al Dyer, Neal Trullson, McBride Aircraft Group, Matthew M. Gosslein, Samuel K. McCauley, Robert E. Hackman from the Aircraft Owners and Pilots Association (AOPA), and Tom Carr from the Cessna Pilots Association (CPA) comment that the FAA should withdraw the NPRM and issue a special airworthiness information bulletin (SAIB). The commenters state that if the aircraft is properly maintained and rigged, then no problems exist; problems should easily be detected visually during routine maintenance; and a rudder system that is built and installed correctly is virtually impossible to jam. The commenters state adequate regulations and requirements are in place to assure the inspection of the rudder system is completed during annual or 100-hour inspections in 14 CFR part 43, Appendix D and in the Cessna service PO 00000 Frm 00009 Fmt 4700 Sfmt 4700 22429 publication. In addition, the commenters point out the following: • Two service difficulty reports were found but none for a jammed rudder. • In the Ohio accident, the rudder stop was installed inverted, and the functionality of the stop configuration was compromised. • If you remove the right rudder return spring and disconnect the right rudder control cable, then the left locked rudder event from the Canadian accident could be duplicated. • The two accident airplanes were not airworthy prior to flight. The commenters further state that requiring replacement of the rudder stop, rudder stop bumper, attachment hardware, and substituting safety wire with jamnuts is an overreaction. The commenters request that the FAA withdraw the NPRM and issue an SAIB since the problem is with a very limited number of airplanes, specifically the Cessna Model 152, and improper maintenance was cited as the cause of the two previously mentioned accidents. The commenters state the airplanes have flown for 51 years and thousands of hours with no previous problems, and installing the original equipment manufacturer (OEM) kit on 17,090 domestic airplanes would put the airplanes at risk. We do not agree that this action should be an SAIB instead of an AD. While the two accident aircraft were not airworthy, the issue that needs to be corrected is a design issue, not a maintenance issue. Follow-on investigations did reveal that rudders on aircraft in full conformity with type design can exceed the travel limits set by the rudder stops. Operation in this non-certificated control position is unacceptable and could cause undesirable consequences. Markings on one accident aircraft correspond with previous contact between the rudder and elevator, and similar markings were noted on several in-service airplanes. We will change the final rule AD to provide another option in lieu of the actions in the proposed AD. For the new option, the limitations section in the airplane flight manual (AFM) and the pilots operating handbook (POH) must be changed to prohibit acrobatics. A placard would be displayed on the instrument panel in clear view of the pilot with the words ‘‘INTENTIONAL SPINS AND OTHER ACROBATIC/ AEROBATIC MANEUVERS PROHIBITED PER AD 2009–10–09.’’ We retain as an option the actions complying with the service information as specified in the proposed AD. After such action is done, the specified E:\FR\FM\13MYR1.SGM 13MYR1

Agencies

[Federal Register Volume 74, Number 91 (Wednesday, May 13, 2009)]
[Rules and Regulations]
[Pages 22426-22429]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-10953]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1131; Directorate Identifier 2008-NE-37-AD; 
Amendment 39-15903; AD 2009-10-08]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Models PW2037, 
PW2037(M), and PW2040 Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
Pratt & Whitney models PW2037, PW2037(M), and PW2040 turbofan engines 
with high-pressure turbine (HPT) 2nd stage hubs that have previously 
been exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 or 
equivalent procedure. This AD requires a onetime optical comparator 
inspection (OCI) of the blade retention slots of the affected HPT 2nd 
stage hubs at the next HPT overhaul after the effective date of the AD. 
This AD results from an uncontained release of HPT 2nd stage blades and 
blade retention lugs. We are issuing this AD to remove nonconforming 
HPT 2nd stage hubs, which could result in an uncontained release of 
turbine blades and blade retention lugs, and damage to the airplane.

DATES: This AD becomes effective June 17, 2009.

ADDRESSES: You can get the service information identified in this AD 
from Pratt & Whitney, 400 Main Street, East Hartford, CT 06108.
    The Docket Operations office is located at Docket Management 
Facility, U.S. Department of Transportation, 1200 New Jersey Avenue 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

FOR FURTHER INFORMATION CONTACT: Mark Riley, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
mark.riley@faa.gov; telephone (781) 238-7758, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed AD. The proposed AD applies to PW models PW2037, 
PW2037(M), and PW2040 turbofan engines. We published the proposed AD in 
the Federal Register on November 14, 2008 (73 FR 67427). That action 
proposed to require inspecting all HPT 2nd stage hubs at the next HPT 
overhaul after the effective date of the AD.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The street address for 
the Docket Operations office (telephone (800) 647-5527) is provided in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Recommend Referring to the Inspection as ``Special Dimensional 
Inspection''

    Pratt & Whitney recommends that the inspection in the proposed AD 
be referred to as a ``Special Dimensional Inspection'' per Pratt & 
Whitney Alert Service Bulletin (ASB) PW2000 72-734, which is approved 
by the FAA. The proposed AD currently specifies an Optical Comparator 
Inspection (OCI). Use of the term ``Special Dimensional Inspection'' 
instead of OCI will provide better alignment with the inspection 
procedures that Pratt & Whitney is presently developing and for which 
it will seek FAA approval, to use as an alternative to OCI.
    We do not agree. The inspection is an OCI. Therefore, identifying 
the type of inspection the AD requires by its name is proper. We did 
not change the AD.

Request To Revise the Estimated Cost

    Pratt & Whitney and two air carriers request that we revise the 
estimated cost to perform an OCI. Pratt & Whitney states that the cost 
is higher than previously anticipated and we should add about $4,000 to 
the cost of each disk overhaul. Delta Air Lines states that the total 
cost is actually closer to $8,000 and it should include shipping 
($1,000), vendor charges ($5,900), and should take into account 
additional inventory required ($180,000 per hub) due to out-of-service 
time required to support the off-site inspection.
    We partially agree. We agree that the cost estimate in the proposed 
AD is not accurate. We do not agree that it should consider shipping 
charges or additional inventory requirements unique to each operator. 
We changed the cost to perform the OCI to $4,000 for each HPT stage 2 
hub as quoted by Pratt & Whitney and updated the total to $3,048,000.

Request for Clarification of the Inspection Being a Onetime Inspection

    Pratt & Whitney and two air carriers request clarification in the 
AD to state that the inspection is a onetime inspection. Also, Delta 
Air Lines comments that repetitive inspections should be required 
unless the cause of the hub out-of-tolerance condition is addressed. 
They also stated that the cause of the hub out-of-tolerance condition 
is not known and repetitive inspections are therefore required.
    We partially agree. We agree that we need to clarify that the OCI 
is a onetime inspection requirement. We changed the AD to clarify that 
the OCI is a onetime inspection requirement. We do not agree that the 
AD should require repetitive inspections. If we determine at a later 
date that repetitive inspections are required, we may issue an AD to 
require them.

Proposal To Eliminate the Fluorescent Penetrant Inspection

    Pratt & Whitney and United Airlines propose that we eliminate the 
fluorescent penetrant inspection (FPI) requirement for the HPT 2nd 
stage hub. FPI of the HPT 2nd stage hub is redundant, since it is 
already mandated per FAA AD 2005-18-03.
    We agree. We changed the AD to only require a onetime OCI of the 
HPT 2nd stage hub after the fluorescent penetrant

[[Page 22427]]

inspection and all shop cleaning processes have been completed.

Proposal To Reduce the Affected Population of HPT 2nd Stage Hubs

    Pratt & Whitney proposes that we reduce the affected population of 
HPT 2nd stage hubs to only those that have been exposed to Pratt & 
Whitney cleaning procedure SPOP 10 or SPOP 9 (cleaning processes that 
have similar abrasive characteristics) during their shop overhaul 
history. Based on recent findings from the NTSB-led investigation, the 
blade slot dimensional variations on the event hub and on other 
inspected hubs resulted from a specific process used during the 
cleaning of hubs during the normal overhaul process.
    We agree. We changed the AD applicability to state that this AD 
applies to Pratt & Whitney models PW2037, PW2037(M), and PW2040 
turbofan engines with HPT 2nd stage hubs that have previously been 
exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 or 
equivalent procedure.

Proposal To Delay Issuance of AD

    United Airlines proposes that we delay issuance of the AD, because 
initial OCI results are showing a 25% reject rate. This suggests that 
the proposed inspections will not detect the problem that led to the 
one industry failure. Otherwise, the industry failure rate would be 
higher. Consequently, issuing the AD would be premature, as the failure 
mechanism is not understood, and it is not clear that the proposed 
inspections will prevent future failures.
    We do not agree. The investigation identified that an out-of-
tolerance condition of the HPT 2nd stage hub blade slots is the cause 
of the failure event. However, the root cause of the out-of-tolerance 
condition is still under investigation, but is believed to have been 
caused by aggressive cleaning with an abrasive media blast. Inspection 
of the HPT 2nd stage hub blade slots is required to identify hubs that 
are out-of-tolerance, to minimize the risk of future failures. Pratt & 
Whitney is reviewing the current acceptance criteria for the OCI of HPT 
2nd stage hub blade slots, and if appropriate, may revise these limits 
to reduce the current reject rate. We did not change the AD.

Proposal To Remove the Reporting Requirement From the AD

    Three air carriers propose that we remove the requirement for 
operators to be responsible for reporting HPT 2nd stage hub OCI results 
within 72 hours of the inspection. Delta Air Lines also asks if they 
are required to report OCI results after the 6-month period, since not 
all of their HPT 2nd stage hubs will go through overhaul within 6 
months. The three air carriers state that it will be extremely 
difficult for operators to comply with the reporting requirements of 
the proposed rule, because it will not be the operators performing the 
inspections. The sole source that performs the inspections, (Pratt & 
Whitney), should be responsible for reporting to the FAA.
    We agree. We removed the reporting requirement from the AD.

Request That an Alternate Inspection Be Developed That Is Not Source-
Approved

    Two air carriers request that an alternate inspection method be 
developed that is not source-approved and will permit all overhaul 
shops the capability to perform the inspection. They state that Pratt & 
Whitney is currently the only source-approved vendor for the OCI. 
Operators are experiencing turn times in excess of 30 days, which is a 
hardship to them.
    We agree that an alternate inspection procedure that can be 
performed by all overhaul facilities is preferred. However, we are 
unaware of any that may exist. We will evaluate any proposed 
alternative inspection an operator may submit as an alternative method 
of compliance. We did not change the AD.

Compliance Time Should Be Revised

    The National Transportation Safety Board (NTSB), states that the 
compliance time should be revised to reflect the recommended compliance 
time in the NTSB Urgent Safety Recommendation A-08-85. That compliance 
time requires removal of all PW2037 2nd stage turbine hubs for 
inspection when they have accumulated significantly fewer hours and/or 
cycles than the incident engine (10,880 hours and/or 4,392 cycles). The 
10,880 hours and 4,392 cycles referenced in A-08-85 were based on the 
time and cycles that the incident engine had accumulated from the last 
overhaul until engine failure. Metallurgical examination of the failed 
hub was not able to discern any fatigue striations, so it is unknown 
how long it took those fatigue cracks to progress to failure. 
Typically, when the cause of the failure, or length of time for a crack 
to progress to failure is unknown, the time and/or cycles, whichever is 
less, since the part was new or overhauled until failure, is divided by 
a factor of two or three to establish a compliance schedule.
    We do not agree. The field management plan defined in the proposed 
AD is based on a risk analysis performed by Pratt &Whitney, which we 
reviewed and concluded is adequate. Further, additional field data 
received to-date has not indicated any increased risk, or that a more 
restrictive field plan is required. We did not change the AD.

Proposed OCI Procedure Should Be Revised

    The NTSB states that the proposed OCI procedure should be revised 
to also require that the blade slots be measured using a coordinate 
measuring machine (CMM) or another dimensional inspection device 
capable of measuring deviations in the center of the blade slots. The 
OCI procedure is limited to only measure the blade slot profile on the 
forward and aft ends of the blade slot. The current procedure does not 
measure the center portion of the blade slot.
    We partially agree. We agree that the current OCI procedure is 
limited such that it cannot measure the center portion of the blade 
slot. However, we disagree that the OCI procedure is not an acceptable 
inspection method to identify non-conforming hubs. We verified that the 
OCI procedure can identify HPT 2nd stage hubs with non-conforming blade 
retention slots. We established limits for OCI that ensured that no 
parts with non-conformances similar to the event hub would be released 
into service. We continue to work with Pratt & Whitney to identify 
other improved inspection methods that can be used as an alternate to 
OCI. We did not change the AD.

AD Compliance Should Also Include Inspection of the HPT 2nd Stage Blade 
Root Serrations for Uneven Contact Wear

    The NTSB states that the AD compliance should also include 
inspection of the HPT 2nd stage blade root serrations for uneven 
contact wear, as defined in the PW2000 Engine Manual, Task 72-52-17-
200-014, Inspection/Check 14. The AD should also specify an action to 
take with the HPT 2nd stage hubs if any HPT 2nd stage blades are 
detected with uneven wear. The HPT 2nd stage blades removed from the 
incident engine showed evidence of uneven contact wear on the blade 
root serrations. The AD should therefore also include inspection of the 
HPT 2nd stage blades and include an action to take with the hub if 
blades are detected to have root serrations with uneven wear.
    We do not agree. Inspection of the HPT 2nd stage blade root 
serrations was

[[Page 22428]]

incorporated in the PW2000 Engine Manual to address a non-conformance 
issue for the blades and is performed during normal inspection. All 
blades that are identified with uneven wear on the root serrations are 
rejected and removed from service. The cause of failure of the incident 
engine was due to a nonconformance of the HPT 2nd stage hub blade 
retention slots. All HPT 2nd stage hubs that have previously been 
exposed to Pratt & Whitney cleaning procedure SPOP 10 or SPOP 9 or 
equivalent procedure will require OCI per the AD. All non-conforming 
hubs will be identified by OCI and removed from service. We did not 
change the AD.

AD Should Mandate That All of the HPT 2nd Stage Hub Blade Slots Be 
Inspected Using OCI

    The NTSB states that the AD should mandate that all of the HPT 2nd 
stage hub blade slots be inspected using OCI. The current procedure 
only requires that every fourth blade retaining slot in the hub be 
inspected. The incident engine had cracks in several adjacent blade 
retaining lugs that resulted in the simultaneous release of multiple 
blades that exceeded the turbine case's containment capability. If only 
every fourth slot in the hub is inspected, then two adjacent 
nonconforming blade slots could slip through the inspection and result 
in an uncontained engine failure.
    We do not agree. Inspecting every fourth blade retaining slot will 
identify all non-conforming hubs. HPT 2nd stage hubs that are 
aggressively cleaned using a grit blast procedure will typically have a 
high number of non-conforming slots. Field inspection data to-date 
indicates that this assumption currently remains valid. We did not 
change the AD.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 762 engines installed on 
airplanes of U.S. registry. We also estimate that it will take about 50 
work-hours per engine to perform the actions, and that the average 
labor rate is $80 per work-hour. No parts are required. Based on these 
figures, we estimate the total cost of the AD to U.S. operators to be 
$3,048,000.

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.
    We are 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.

Regulatory Findings

    We have determined that 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) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); 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.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration 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:

2009-10-08 Pratt & Whitney: Amendment 39-15903. Docket No. FAA-2008-
1131; Directorate Identifier 2008-NE-37-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective June 17, 
2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney models PW2037, PW2037(M), 
and PW2040 turbofan engines with high-pressure turbine (HPT) 2nd 
stage hubs that have previously been exposed to Pratt & Whitney 
cleaning procedure SPOP 10 or SPOP 9 or equivalent procedure. These 
engines are installed on, but not limited to, Boeing 757-200 and 
757-300 airplanes.

Unsafe Condition

    (d) This AD results from an uncontained release of HPT 2nd stage 
blades and blade retention lugs. We are issuing this AD to remove 
nonconforming HPT 2nd stage hubs, which could result in an 
uncontained release of turbine blades and blade retention lugs, and 
damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed at the next HPT overhaul, unless the actions have 
already been done.

Onetime Optical Comparator Inspection (OCI) of HPT 2nd Stage Hubs

    (f) Perform a onetime optical comparator inspection of the HPT 
2nd stage hubs after a fluorescent penetrant inspection and all shop 
cleaning processes have been completed. Pratt & Whitney Alert 
Service Bulletin No. PW2000 A72-734, dated November 3, 2008, 
contains information about the optical comparator inspection.
    (g) Remove from service any hubs that fail the optical 
comparator inspection.

Definition

    (h) This AD defines an HPT overhaul as when the HPT is at its 
piece-part level.

Alternative Methods of Compliance

    (i) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (j) Contact Mark Riley, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: mark.riley@faa.gov; 
telephone (781) 238-7758, fax (781) 238-7199, for more information 
about this AD.
    (k) Pratt & Whitney Alert Service Bulletin No. PW2000 A72-734, 
dated November 3, 2008, contains information about the optical 
comparator inspection.

[[Page 22429]]

Material Incorporated by Reference

    (l) None.


    Issued in Burlington, Massachusetts, on May 4, 2009.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E9-10953 Filed 5-12-09; 8:45 am]
BILLING CODE 4910-13-P