Airworthiness Directives; Boeing Model 757 Airplanes, 16721-16725 [E6-4827]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 71, Number 64 (Tuesday, April 4, 2006)]
[Proposed Rules]
[Pages 16721-16725]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-4827]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20689; Directorate Identifier 2004-NM-197-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757 Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of 
comment period.

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SUMMARY: The FAA is revising an earlier proposed airworthiness 
directive (AD) for certain Boeing Model 757 airplanes. The original 
NPRM would have required, for certain airplanes, reworking the spar 
bonding path and reapplying sealant; and, for certain other airplanes, 
testing the electrical bond between the engine fuel feed hose and the 
wing front spar and, if applicable, reworking the spar bonding path and 
reapplying sealant. The original NPRM also would have required, for all 
airplanes, an inspection to ensure the electrical bonding jumper is 
installed between the engine fuel feed tube and the adjacent wing 
station. The original NPRM resulted from fuel system reviews conducted 
by the manufacturer. This action revises the original NPRM by requiring 
operators that may have installed an incorrect O-ring to install the 
correct part and do a re-test. We are proposing this supplemental NPRM 
to prevent arcing or sparking at the interface between the bulkhead 
fittings of the engine fuel feed tube and the front spar during a 
lightning strike, which could provide a possible ignition source for 
the fuel vapor inside the fuel tank and result in a fuel tank 
explosion.

DATES: We must receive comments on this supplemental NPRM by May 1, 
2006.

ADDRESSES: Use one of the following addresses to submit comments on 
this supplemental NPRM.
     DOT Docket Web site: Go to https://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to https://
www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.

[[Page 16722]]

    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Tom Thorson, Aerospace Engineer, 
Propulsion Branch, ANM-140S, Seattle Aircraft Certification Office, 
FAA,1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6508; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this supplemental NPRM. Send your comments to an 
address listed in the ADDRESSES section. Include the docket number 
``Docket No. FAA-2005-20689; Directorate Identifier 2004-NM-197-AD'' at 
the beginning of your comments. We specifically invite comments on the 
overall regulatory, economic, environmental, and energy aspects of this 
supplemental NPRM. We will consider all comments received by the 
closing date and may amend this supplemental NPRM in light of those 
comments.
    We will post all comments submitted, without change, to https://
dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this supplemental NPRM. Using the search function 
of that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit https://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at https://
dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level in the Nassif Building at the DOT 
street address stated in ADDRESSES. Comments will be available in the 
AD docket shortly after the Docket Management System receives them.

Discussion

    We proposed to amend 14 CFR part 39 with a notice of proposed 
rulemaking (NPRM) for an AD (the ``original NPRM'') for certain Boeing 
Model 757 airplanes. The original NPRM was published in the Federal 
Register on March 23, 2005 (70 FR 14594). The original NPRM proposed to 
require, for certain airplanes, reworking the spar bonding path and 
reapplying sealant; and, for certain other airplanes, testing the 
electrical bond between the engine fuel feed hose and the wing front 
spar and, if applicable, reworking the spar bonding path and reapplying 
sealant. The original NPRM also proposed to require, for all airplanes, 
an inspection to ensure the electrical bonding jumper is installed 
between the engine fuel feed hose and the adjacent wing station.

Actions Since Original NPRM Was Issued

    Since we issued the original NPRM, the manufacturer informed us 
that a part number (P/N) for an O-ring installation was identified 
incorrectly in Boeing Alert Service Bulletin 757-28A0076 and Boeing 
Alert Service Bulletin 757-28A0077, both dated August 27, 2004. These 
service bulletins were referenced as the appropriate source of service 
information for accomplishing the required actions in the original 
NPRM. This supplemental NPRM (SNPRM) will propose to require compliance 
with Revision 1 of the service bulletins, which cite the O-ring's P/N 
correctly. For Group 1 airplanes on which the installation was done in 
accordance with the original issue of the service bulletins, and for 
Group 2 airplanes that failed the bonding resistance test done in 
accordance with the original NPRM, this SNPRM will propose to require 
installing an O-ring with the correct P/N and doing a re-test.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 757-28A0076, Revision 1, 
dated October 20, 2005; and Boeing Service Bulletin 757-28A0077, 
Revision 1, dated October 20, 2005. The service bulletins describe 
procedures that are essentially the same as those described in the 
original NPRM, except the service bulletins, Revision 1, identify the 
correct part number for the O-ring. However, the service bulletins 
describe additional work for airplanes that incorporated the initial 
releases of the service bulletins. The additional work includes 
disassembling the coupling for the engine fuel feed tube at the front 
spar (left and right wings), and replacing the O-ring that has the 
incorrect P/N with a new O-ring with the correct P/N. The additional 
work also includes doing a leak test of the re-assembled coupling. 
Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

Comments

    We have considered the following comments about the original NPRM.

Request To Extend Compliance Time

    The Air Transport Association (ATA), Continental Airlines, United 
Airlines, Delta Airlines, U.S. Airways, and American Airlines request 
that we extend the proposed compliance time for doing the bonding 
resistance test and for inspecting the electrical bonding jumper. The 
commenters request that we extend the compliance time from 48 months to 
either 60 months or 72 months. The commenters request the extension to 
all of the AD actions to be scheduled to coincide with heavy 
maintenance intervals when other activities that require entering the 
fuel tank are also scheduled. The commenters state that extending the 
compliance time would minimize the number of fuel tank entries and also 
minimize the manpower requirements for draining the tank and doing 
entry procedures. Several commenters note that AD 2004-10-06, amendment 
39-13636 (69 FR 28046, May 18, 2004), which is a similar AD for 
hydraulic tube bonding in the fuel tank for lightning protection, has a 
compliance time of 60 months, which provides an adequate level of 
safety. One commenter notes that there have been no large-jet transport 
accidents related to lightning strikes or bonding-related hazards since 
1977, when the FAA strengthened certification standards for bonding. 
The same commenter notes that there have been no lightning-induced fuel 
tank events on Boeing Model 757 airplanes.
    We partially agree with the commenters. We agree with extending the 
compliance time to 60 months because we have assessed these specific 
actions on other Boeing airplane models and we have evaluated similar 
ADs such as AD 2004-10-06, and AD 2005-04-01, amendment 39-13973 (70 FR 
7841, February 16, 2005). In addition, we find that extending the 
compliance time will not adversely affect safety. The manufacturer 
supports extending the compliance time to 60 months, and Revision 1 of 
Boeing Service Bulletins 757-28A0076 and 757-28A0077 include this 
revised time. We do not agree with extending the compliance time to 72 
months. The commenters that request this extension do not provide a 
technical justification; however, operators may request an alternate 
method of compliance (AMOC) in accordance with the procedures in 
paragraph letter (l) of this proposed AD.

[[Page 16723]]

Request To State that Bonding Jumper Is Attached to a Fuel Tube

    The Boeing Company requests that we revise three sections of the 
proposed AD in order to correctly identify that the bonding jumper is 
attached to a fuel tube mating with a fuel hose end fitting, and not 
with the fuel hose. Boeing states that this change will clarify that 
the electrical bonding jumper is installed between the engine fuel feed 
tube and the adjacent wing section.
    We agree. The suggested wording will clarify the proposed AD. We 
have changed the ``Summary'' section and paragraph (i) of the proposed 
AD as requested. However, we have not changed the ``Relevant Service 
Information'' section because that section of the SNPRM does not 
contain the same information as the same section of the original NPRM.

Request To Correct Discrepancies in Service Bulletins

    Continental Airlines states that the Work Instructions in Boeing 
Alert Service Bulletins 757-28A0076 and 757-28A0077, both dated August 
27, 2004, have discrepancies that prevent accomplishing certain 
proposed actions. Specifically, the following items are not included in 
the alert service bulletins: Removal and installation instructions for 
the forward flap track fairing; a statement that a special tool is 
required for removing and reinstalling the forward fitting of the fuel 
feedline; and a note to clarify that leak tests of the fuel system are 
required following rework. Continental states that alternative rework 
instructions would have to be approved as AMOCs for each airplane to 
comply successfully with the requirements of the proposed AD.
    We partially agree. We agree that a note that leak tests of the 
fuel system are necessary following rework would clarify the service 
bulletin; Boeing has added this note to Revision 1 of Boeing Service 
Bulletins 757-28A0076 and 757-28A0077. Also, Boeing verified that a 
special tool is not necessary because a standard ``crow's foot'' tool 
is readily available that is sufficient to complete the task. In 
addition, the instructions for removing and reinstalling the forward 
fitting are already included in the service bulletins by reference to 
the applicable airplane maintenance manuals (AMM). Boeing can answer 
additional questions if the commenter requires further information. We 
disagree that it is necessary for us to mandate the changes proposed by 
Continental because these changes have to do with the content of the 
service bulletins rather than the content of this proposed AD, and they 
do not affect the AD action. No changes to the proposed AD are 
necessary.

Request To Revise Cost Estimate

    The ATA, American Airlines, and Delta Airlines request that we 
revise the hours estimated to complete the proposed actions. The 
commenters state that the estimates do not accurately reflect the 
operations required for defueling, access, and other prerequisites for 
the proposed actions.
    We disagree. The cost estimate discussed in AD rulemaking actions 
represents only the time necessary to perform the specific actions 
actually required by the AD. These figures typically do not include 
incidental costs, such as the time required to gain access and close 
up, planning time, or time necessitated by other administrative 
actions. However, Boeing updated the work-hour estimates for the 
bonding test and sealant application, and for the bonding test, hose 
fitting and spar bonding rework, and sealant application. These changes 
are reflected in the Cost Estimate table below.
    In addition, after the original NPRM was issued, we reviewed the 
figures we have used over the past several years to calculate AD costs 
to operators. To account for various inflationary costs in the airline 
industry, we find it necessary to increase the labor rate used in these 
calculations from $65 per work hour to $80 per work hour. The costs of 
compliance, below, reflect this increase in the specified hourly labor 
rate.

Request To Remove Rework Requirement for Certain Conditions

    Delta Airlines states that, for certain airplanes, Boeing Alert 
Service Bulletins 757-28A0076 and 757-28A0077 require removing, 
cleaning, and re-installing the fuel feedline fitting to ensure an 
adequate bond is present for lightning protection. Delta requests that 
we revise the proposed AD to require reworking the fitting only if a 
preliminary resistance measurement fails. Delta states that the 
proposed AD does not take into account installations that may have been 
completed per the revised AMM procedures, which are consistent with the 
service information.
    We disagree. The resistance measurement by itself does not ensure 
that an adequate bond is present for lightning protection. The only way 
to ensure the presence of an adequate bond capable of carrying the 
heavy electrical currents that are caused by an attached lightning 
strike is by a rigorous cleaning and assembly process, with an 
electrical bonding check as a final measure to ensure proper assembly. 
However, interested parties may submit an AMOC in accordance with the 
procedures in paragraph letter (l) of this proposed AD, if they can 
substantiate the following: That an airplane has a fuel feedline 
fitting that is installed in accordance with a procedure equivalent to 
the service bulletins referenced in the proposed AD; and that the 
current resistance measurement is within the value required by the 
service bulletins. No changes to the proposed AD are necessary.

Request To Revise ``Discussion'' Section

    The Boeing Company requests that we revise the ``Discussion'' 
section to be similar to that provided in NPRM Docket No. FAA-2004-
19680 (69 FR 68272, November 24, 2004). Boeing states that the issue 
addressed in this proposed AD is similar to that in NPRM Docket No. 
FAA-2004-19680 in that it was identified before the SFAR 88 safety 
assessment. Boeing states that the ``Discussion'' section does not 
reflect this fact.
    We disagree. Although the issue was identified before the Special 
Federal Aviation Regulation No. 88 (``SFAR 88,'' Amendment 21-78, and 
subsequent Amendments 21-82 and 21-83) safety assessment, the non-
compliance was identified and included in the Boeing 757 SFAR 88 Safety 
Analysis documents. This non-compliance was tracked administratively 
and identified as an unsafe condition requiring AD action through the 
SFAR 88 process. Therefore, it is considered an SFAR 88-related AD. No 
changes to the proposed AD are necessary.

FAA's Determination and Proposed Requirements of the SNPRM

    Certain changes discussed above expand the scope of the original 
NPRM; therefore, we have determined that it is necessary to reopen the 
comment period to provide additional opportunity for public comment on 
this SNPRM.

Difference Between the SNPRM and the Service Bulletins

    Although the referenced service bulletins would allow an operator's 
equivalent procedures to be used for aircraft maintenance manuals (AMM) 
referenced in the service bulletins, this proposed AD would require you 
to use the referenced AMMs except as provided in paragraph (k) of this 
SNPRM.

Clarification of AMOC Paragraph

    We have revised this action to clarify the appropriate procedure 
for notifying the principal inspector before using any

[[Page 16724]]

approved AMOC on any airplane to which the AMOC applies.

Costs of Compliance

    There are about 1,040 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 700 airplanes of 
U.S. registry. The average labor rate is estimated to be $80 per work 
hour. Parts would be supplied from operator stock. The following table 
provides the estimated costs for U.S. operators to comply with this 
proposed AD.

                             Estimated Costs
------------------------------------------------------------------------
                                                               Cost per
           Action/airplanes affected             Work hours    airplane
------------------------------------------------------------------------
Hose fitting and spar bonding rework and                 11         $880
 sealant application (Group 1 airplanes)......
Bonding test and sealant application (Group 2            12          960
 airplanes that pass bonding test)............
Bonding test, hose fitting and spar bonding              18        1,440
 rework and sealant application (Group 2
 airplanes that fail bonding test)............
Replace O-ring for airplanes that incorporated            3          240
 original release of the service bulletins....
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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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 the proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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 regulatory evaluation of the estimated costs to 
comply with this supplemental NPRM and placed it in the AD docket. See 
the ADDRESSES section for a location to examine the regulatory 
evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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.


Sec.  39.13  [Amended]

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

Boeing: Docket No. FAA-2005-20689; Directorate Identifier 2004-NM-
197-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by May 1, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 757-200, -200PF, and -200CB, 
series airplanes as identified in Boeing Alert Service Bulletin 757-
28A0076, Revision 1, dated October 20, 2005; and Model 757-300 
series airplanes as identified in Boeing Alert Service Bulletin 757-
28A0077, Revision 1, dated October 20, 2005; certificated in any 
category.

Unsafe Condition

    (d) This AD resulted from fuel system reviews conducted by the 
manufacturer. We are issuing this AD to prevent arcing or sparking 
at the interface between the bulkhead fittings of the engine fuel 
feed tube and the front spar during a lightning strike, which could 
provide a possible ignition source for the fuel vapor inside the 
fuel tank and result in a fuel tank explosion.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Service Bulletin References

    (f) The term ``service bulletin(s),'' as used in this AD, means 
the Accomplishment Instructions of the following service bulletins, 
as applicable.
    (1) For Model 757-200, -200CB, and -200PF series airplanes: 
Boeing Service Bulletin 757-28A0076, Revision 1, dated October 20, 
2005.
    (2) For Model 757-300 series airplanes: Boeing Service Bulletin 
757-28A0077, Revision 1, dated October 20, 2005.

Hose Fitting and Spar Bonding Rework and Sealant Application

    (g) For Group 1 airplanes as identified in the service 
bulletins: Within 60 months after the effective date of this AD, 
rework the spar bonding path between the end fitting of the fuel 
feed hose and the front spar, and apply sealant to the hose fitting 
on the forward and aft side of the front spar and to the fitting and 
tube coupling on both sides of the dry bay wall, in accordance with 
the applicable service bulletin.

Bonding Resistance Test

    (h) For Group 2 airplanes as identified in the service 
bulletins: Within 60 months after the effective date of this AD, do 
a bonding resistance test between the fuel feed hose and the front 
spars of the left and right wings, in accordance with the service 
bulletins.
    (1) If the test meets required resistance limits, before further 
flight, apply sealant to the end fitting of the fuel feed hose on 
the aft side of the front spar and to the fitting and tube coupling 
on both sides of the dry bay wall, in accordance with the applicable 
service bulletin.
    (2) If the test does not meet required resistance limits, before 
further flight, remove any existing sealant at the front spar; 
rework the spar bonding path between the end fitting of the fuel 
feed hose and the front spar to meet bonding resistance test 
requirements; and apply sealant to the end fitting of the fuel feed 
hose on the forward and aft sides of the front spar, and to the 
fitting and tube

[[Page 16725]]

coupling on both sides of the dry bay wall, in accordance with the 
applicable service bulletin.

Inspection of Electrical Bonding Jumper

    (i) For all airplanes as identified in the service bulletins: 
Within 60 months after the effective date of this AD, perform a 
general visual inspection and applicable corrective actions to 
ensure that an electrical bonding jumper is installed between the 
engine fuel feed tube and the adjacent wing station 285.65 rib in 
the left and right wing fuel tanks, in accordance with the service 
bulletins.

Replacement of O-Ring and Test

    (j) For airplanes on which the actions in paragraphs (g) or 
(h)(2) of this AD were done before the effective date of this AD in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 757-28A0076, dated August 27, 2004; and Boeing 
Alert Service Bulletin 757-28A0077, dated August 27, 2004; as 
applicable: Within 60 months after the effective date of this AD, 
replace the O-ring, part number (P/N) MS29513-330 with a new O-ring, 
P/N MS29513-328, and do a leak test before further flight after 
reassembly. Do all actions in accordance with Part B of the 
Accomplishment Instructions of the applicable service bulletin.

Exception to Accomplishment Instructions in Service Bulletins

    (k) Although Boeing Service Bulletin 757-28A0076, Revision 1, 
and Boeing Service Bulletin 757-28A0077, Revision 1, both dated 
October 20, 2005, permit operator's equivalent procedures (OEP), 
this AD would require you to use the referenced Airplane Maintenance 
Manuals, except that operators may use their own FAA-approved OEPs 
to drain the left and right engine fuel tubes, to drain and 
ventilate the fuel tanks, and to enter the fuel tanks.

Actions Accomplished in Accordance With Original Issues of Service 
Bulletins

    (l) Actions done before the effective date of this AD in 
accordance with Boeing Service Bulletin 757-28A0076, and Boeing 
Service Bulletin 757-28A0077, both dated August 24, 2004, are 
acceptable for compliance only with the requirements of paragraph 
(h)(1) of this AD.

Alternative Methods of Compliance (AMOCs)

    (m)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

    Issued in Renton, Washington, on March 24, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-4827 Filed 4-3-06; 8:45 am]
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