Airworthiness Directives; Boeing Model 777-200, 777-300, and 777-300ER Series Airplanes

[Federal Register Volume 72, Number 82 (Monday, April 30, 2007)]
[Rules and Regulations]
[Pages 21079-21083]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-7853]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-23842; Directorate Identifier 2005-NM-145-AD; 
Amendment 39-15034; AD 2007-09-04]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200, 777-300, and 777-
300ER Series Airplanes

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

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Boeing Model 777-200, 777-300, and 777-300ER series airplanes. 
This AD requires repetitive inspections for discrepancies of the 
splined components that support the inboard end of the inboard trailing 
edge flap; related investigative, corrective, and other specified 
actions if necessary; a one-time modification of the inboard support of 
the inboard trailing edge flap by installing a new isolation strap and 
attachment hardware; and repetitive replacement of the torque tube 
assembly. For certain Boeing Model 777-200 series airplanes, this AD 
also specifies prior or concurrent accomplishment of one-time 
inspections of the flap seal panels for cracking and minimum 
clearances, and of the torque tubes for damage; and related 
investigative and corrective actions if necessary. This AD also 
provides a terminating action (modification of the inboard main flap) 
for the repetitive inspections. This AD results from reports of 
corrosion on the torque tube and closeout rib fittings that support the 
inboard end of the inboard trailing edge flap, as well as a structural 
reassessment of the torque tube joint that revealed the potential for 
premature fatigue cracking of the torque tube that would not be 
detected using reasonable inspection methods. We are issuing this AD to 
detect and correct corrosion or cracking of the torque tube and 
closeout rib fittings that support the inboard end of the inboard 
trailing edge flap. Cracking in these components could lead to a

[[Page 21080]]

fracture, which could result in loss of the inboard trailing edge flap 
and consequent reduced controllability of the airplane.

DATES: This AD becomes effective June 4, 2007.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of June 4, 2007.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
Room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Gary Oltman, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6443; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the AD docket on the Internet at http://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 of the Nassif Building at the street address stated in the 
ADDRESSES section.

Discussion

    The FAA issued a supplemental notice of proposed rulemaking (NPRM) 
to amend 14 CFR part 39 to include an AD that would apply to certain 
Boeing Model 777-200 and 777-300 series airplanes. That supplemental 
NPRM was published in the Federal Register on October 3, 2006 (71 FR 
58314). That supplemental NPRM proposed to require repetitive 
inspections for discrepancies of the splined components that support 
the inboard end of the inboard trailing edge flap; related 
investigative, corrective, and other specified actions if necessary; a 
one-time modification of the inboard support of the inboard trailing 
edge flap by installing a new isolation strap and attachment hardware; 
and repetitive replacement of the torque tube assembly. That 
supplemental NPRM also specified prior or concurrent accomplishment, 
for certain Boeing Model 777-200 series airplanes, of one-time 
inspections of the flap seal panels for cracking and minimum 
clearances, and of the torque tubes for damage; and related 
investigative and corrective actions if necessary. That supplemental 
NPRM also provided a terminating action (modifying the inboard main 
flap) for the repetitive inspections.

Comments

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

Support for the Supplemental NPRM

    Boeing, Continental Airlines, and United Airlines concur with the 
contents of the supplemental NPRM.

Request To Clarify Inspection Threshold

    United Airlines would like to know if the inspection threshold 
limits specified in paragraph (l)(2) of the supplemental NPRM should be 
applied from the airplane manufacture date or after the accomplishment 
of the torque tube assembly replacement done in accordance with 
paragraph (l)(1). The compliance times in the proposed rule are 
accomplished in accordance with the service bulletin, which requires 
the inspections to be accomplished at the times and intervals noted in 
the Boeing 777 Maintenance Planning Document (MPD). The MPD has 
inspection thresholds based on the time in service rather than the 
torque tube assembly replacement done in accordance with paragraph 
(l)(1) of the supplemental NPRM.
    We agree that this threshold for inspection needs clarification. 
Therefore, we have added a clarification in the AD to permit the use of 
a threshold measured from the actions done in accordance with paragraph 
(l)(1) of this AD, rather than delivery of the airplane, as specified 
in paragraph (l)(2) of the AD. However, the conservative method of 
measuring the threshold from delivery of the airplane may still be 
used.

Request To Clarify Inspection Requirement

    Continental Airlines states that the supplemental NPRM seems to 
indicate that the initial inspection in paragraph (h) must be 
accomplished for the splined components before the modification done in 
accordance with Boeing Service Bulletin 777-57-0054, dated February 23, 
2006, can be performed. Continental does not believe it is necessary to 
perform the initial inspection when the splined component will be 
replaced with new or improved parts per the modification. Continental 
believes that the AD should have a provision to allow upfront 
modification of the splined components without doing the inspections in 
accordance with Boeing Service Bulletin 777-57A0048, Revision 1, dated 
June 9, 2005.
    We agree that it is not necessary in this circumstance to do the 
initial inspection. Replacing certain parts with new or improved parts 
in accordance with Boeing Service Bulletin 777-57-0054 terminates the 
inspections specified in Boeing Service Bulletin 777-57A0048, Revision 
1. Therefore, we have clarified paragraphs (h) and (l)(1) of the AD to 
help avoid potential confusion and unnecessary inspection.

Requests Regarding Service Information

    The Modification and Replacement Parts Association (MARPA) requests 
that service documents essential to the accomplishment of the 
supplemental NPRM be (1) incorporated by reference into the regulatory 
document, and (2) published in the docket management system (DMS).
    We infer that MARPA would like to have documents incorporated by 
reference during the NPRM phase of rulemaking. We do not agree that 
documents should be incorporated by reference during the NPRM phase of 
rulemaking. The Office of the Federal Register (OFR) requires that 
documents that are necessary to accomplish the requirements of the AD 
be incorporated by reference during the final rule phase of rulemaking. 
This final rule incorporates by reference the document necessary for 
the accomplishment of the actions required by this AD. Further, we 
point out that while documents that are incorporated by reference do 
become public information, they do not lose their copyright protection. 
For that reason, we advise the public to contact the manufacturer to 
obtain copies of the referenced service information.
    In regard to the commenter's request to post service bulletins on 
the Department of Transportation's DMS, we are currently in the process 
of reviewing issues surrounding the posting of service bulletins on DMS 
as part of an AD docket. Once we have thoroughly examined all aspects 
of this issue and have made a final determination, we will consider 
whether our current practice needs to be revised. No change to the 
final rule is necessary in response to this comment.

Request To Reference Defective Parts Manufacturer Approval (PMA) Parts

    The same commenter also requests that the supplemental NPRM be

[[Page 21081]]

modified to consider the possibility of defective PMA parts and permit 
the use of PMA parts that meet the ``new and improved'' criteria 
pursuant to existing laws and regulations and the issues set forth in 
the current proposed regulatory action.
    We recognize the need for standardization of this issue and we are 
currently in the process of reviewing issues that address the use of 
PMAs in ADs at the national level. However, the Transport Airplane 
Directorate considers that to delay this particular AD action would be 
inappropriate, since we have determined that an unsafe condition exists 
and that replacement of certain parts must be accomplished to ensure 
continued safety. Therefore, no change has been made to the AD in this 
regard.

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

    There are about 353 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this AD, at an average labor rate of $80 
per work hour.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                Number of U.S.-
            Action                Work hours        Parts         Cost per        registered        Fleet cost
                                                                  airplane         airplanes
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Detailed inspection for        20..............         None  $1,600, per      132.............  $211,200, per
 discrepancies of the splined                                  inspection                         inspection
 components.                                                   cycle.                             cycle.
Modification (installing       Negligible......      $17,156  $17,156........  132.............  $2,264,592.
 isolation strap and
 hardware).
Replacement of torque tube     Negligible \1\..       24,230  $24,230........  132.............  $3,198,360, per
 assembly.                                                                                        replacement
                                                                                                  cycle.
Modification (terminating      32 to 36,             145,659  $148,219 to      132.............  $19,564,908 to
 action).                       depending on                   148,539.                           19,607,148.
                                airplane
                                configuration.
Prior or concurrent            1...............         None  $80............  Up to 132.......  As much as
 inspection.                                                                                      $10,560.
----------------------------------------------------------------------------------------------------------------
\1\ Provided that the replacement is performed at the same time as a scheduled inspection.

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 regulatory evaluation of the estimated costs to 
comply with this AD 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

2007-09-04 Boeing: Amendment 39-15034. Docket No. FAA-2006-23842; 
Directorate Identifier 2005-NM-145-AD.

Effective Date

    (a) This AD becomes effective June 4, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 777-200, -300, and -300ER 
series airplanes, certificated in any category; as identified in 
Boeing Service Bulletin 777-57-0054, dated February 23, 2006.

Unsafe Condition

    (d) This AD results from reports of corrosion on the torque tube 
and closeout rib fittings that support the inboard end of the 
inboard trailing edge flap, as well as a structural reassessment of 
the torque tube joint that revealed the potential for premature

[[Page 21082]]

fatigue cracking of the torque tube that would not be detected using 
reasonable inspection methods. We are issuing this AD to detect and 
correct corrosion or cracking of the torque tube and closeout rib 
fittings that support the inboard end of the inboard trailing edge 
flap. Cracking in these components could lead to a fracture, which 
could result in loss of the inboard trailing edge flap and 
consequent reduced controllability of the airplane.

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 Reference

    (f) The term ``service bulletin,'' as used in paragraphs (g), 
(h), (i), (j), and (k) of this AD, means Boeing Service Bulletin 
777-57A0048, Revision 1, dated June 9, 2005.
    (g) Where the service bulletin specifies a compliance time after 
the issuance of the service bulletin, this AD requires compliance 
within the specified compliance time after the effective date of 
this AD.

Initial Inspection

    (h) For all airplanes: Do a detailed inspection for any 
discrepancy of the splined components of the inboard trailing edge 
flap, in accordance with the Accomplishment Instructions of the 
service bulletin. The splined components of the inboard trailing 
edge flap include the torque tube, closeout rib fitting assembly, 
carrier beam pillow block fitting assembly, and drive crank support. 
Discrepancies of the torque tube and closeout rib fitting include 
light contact wear, corrosion pits, corrosion, cracking, or 
fracture. Discrepancies of the carrier beam pillow block fitting 
assembly and drive crank support consist of light contact wear and 
damage to the cadmium plating. Do the initial inspection at the 
applicable time specified in Table 7 under paragraph 1.E., 
``Compliance,'' of the service bulletin, except as provided by 
paragraph (g) of this AD. Doing the modification in paragraph (l)(1) 
of this AD terminates the inspection requirements of this paragraph.

    Note 1: For the purposes of this AD, a detailed inspection is: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

No Discrepancy/Other Specified Actions

    (i) If no discrepancy is found during the inspection required by 
paragraph (h) of this AD, perform all applicable specified actions, 
including the modification to install a new isolation strap and 
attachment hardware, in accordance with the Accomplishment 
Instructions of the service bulletin. Then, repeat the inspection at 
the applicable time specified in Table 7 under paragraph 1.E., 
``Compliance,'' of the service bulletin. Doing the modification in 
paragraph (l)(1) of this AD terminates the repetitive inspection 
requirements of this paragraph.

Related Investigative/Corrective/Other Specified Actions and 
Repetitive Inspections

    (j) For any discrepancy found during any inspection required by 
paragraphs (h) and (i) of this AD: Before further flight, accomplish 
all applicable related investigative, corrective, and other 
specified actions, including the modification to install a new 
isolation strap and attachment hardware, in accordance with the 
Accomplishment Instructions of the service bulletin. Then, evaluate 
the spline rework to determine the appropriate repetitive interval, 
in accordance with the Accomplishment Instructions of the service 
bulletin. Thereafter, repeat the inspection at the applicable 
interval specified in Table 7 under paragraph 1.E., ``Compliance,'' 
of the service bulletin. Doing the modification in paragraph (l)(1) 
of this AD terminates the repetitive inspection requirements of this 
paragraph.

Replacement of Torque Tube Assembly

    (k) For all airplanes: Replace the torque tube assembly with a 
new torque tube assembly, in accordance with the Accomplishment 
Instructions of the service bulletin. Do the initial replacement at 
the applicable compliance time specified in Notes (c) and (d), as 
applicable, of Table 7 in paragraph 1.E., ``Compliance,'' of the 
service bulletin, except as provided by paragraph (g) of this AD. 
Repeat the replacement thereafter at the applicable interval 
specified in Notes (c) and (d), of Table 7 under paragraph 1.E., 
``Compliance,'' of the service bulletin. Doing the modification in 
paragraph (l)(1) of this AD terminates the repetitive replacement 
requirements of this paragraph.

Modification

    (l) For all airplanes: Within 60 months after the effective date 
of this AD, do the actions in paragraphs (l)(1) and (l)(2) of this 
AD.
    (1) Modify the inboard main flap in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 777-57-0054, 
dated February 23, 2006. Doing this modification terminates the 
repetitive requirements of paragraphs (i), (j), and (k), of this AD; 
and inspection requirements of the splined components of the torque 
tube and the closeout rib fitting assemblies, as required by 
paragraph (h) of this AD.
    (2) Revise the FAA-approved maintenance inspection program for 
performing periodic inspections and maintenance of the torque tube 
splined joints in accordance with the Accomplishment Instructions of 
Boeing Service Bulletin 777-57-0054, dated February 23, 2006. For 
the purpose of the inspections required by this paragraph, the 
inspection threshold may be measured from the installation of the 
modification required by paragraph (l)(1) of this AD.

Concurrent Requirement

    (m) For Boeing Model 777-200 series airplanes, as identified in 
Boeing Service Bulletin 777-27-0034, Revision 1, dated April 20, 
2006: Prior to or concurrently with the actions in paragraph (l) of 
this AD, do a general visual inspection of the flap seal panels for 
cracking and minimum clearances, and a detailed inspection of the 
torque tubes for damage; and do all applicable related investigative 
and corrective actions before further flight. Do all actions in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 777-27-0034, Revision 1, dated April 20, 2006; except where 
the service bulletin specifies the corrective action of replacing 
the torque tube, the replacement must be done in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 777-57-0054, 
dated February 23, 2006.

    Note 2: For the purposes of this AD, a general visual inspection 
is: ``A visual examination of an interior or exterior area, 
installation, or assembly to detect obvious damage, failure, or 
irregularity. This level of inspection is made from within touching 
distance unless otherwise specified. A mirror may be necessary to 
ensure visual access to all surfaces in the inspection area. This 
level of inspection is made under normally available lighting 
conditions such as daylight, hangar lighting, flashlight, or 
droplight and may require removal or opening of access panels or 
doors. Stands, ladders, or platforms may be required to gain 
proximity to the area being checked.''

Actions Done in Accordance With Previous Issues of Service Bulletins

    (n) Actions done before the effective date of this AD in 
accordance with Boeing Service Bulletin 777-27-0034, dated February 
11, 1999; or Boeing Alert Service Bulletin 777-57A0048, dated 
September 9, 2004; are acceptable for compliance with the 
corresponding actions of this AD.

Alternative Methods of Compliance (AMOCs)

    (o)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
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.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane.

Material Incorporated by Reference

    (p) You must use the service information specified in Table 1 of 
this AD to perform the actions that are required by this AD, unless 
the AD specifies otherwise. The Director of the Federal Register 
approved the incorporation by reference of these documents in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing 
Commercial Airplanes, P.O. Box 3707,

[[Page 21083]]

Seattle, Washington 98124-2207, for a copy of this service 
information. You may review copies at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 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/cfr/ibr-locations.html.

              Table 1.--Material Incorporated by Reference
------------------------------------------------------------------------
   Boeing Service Bulletin      Revision level            Date
------------------------------------------------------------------------
777-27-0034..................  1..............  April 20, 2006.
777-57-0054..................  Original.......  February 23, 2006.
777-57A-0048.................  1..............  June 9, 2005.
------------------------------------------------------------------------


    Issued in Renton, Washington, on April 17, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-7853 Filed 4-27-07; 8:45 am]
BILLING CODE 4910-13-P

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