[Federal Register Volume 72, Number 17 (Friday, January 26, 2007)]
[Rules and Regulations]
[Pages 3715-3718]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-1081]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24891; Directorate Identifier 2006-NM-080-AD; 
Amendment 39-14910; AD 2007-02-23]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200, -300, and -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, -300, and -300ER series airplanes. This 
AD requires replacement of the gimbal plates of the left and right 
outboard trailing edge flaps with improved gimbal plates and other 
specified actions. This AD results from a broken pivot link found on 
the inboard support for the outboard trailing edge flap. We are issuing 
this AD to prevent disconnection of the drive arm from its drive 
gimbal, due to a broken pivot link on an outboard flap support, which 
could result in unexpected roll of the airplane and loss of control of 
the airplane.

DATES: This AD becomes effective March 2, 2007.
    The Director of the Federal Register approved the incorporation by 
reference

[[Page 3716]]

of a certain publication listed in the AD as of March 2, 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 airworthiness directive (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 notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to certain Boeing Model 
777-200, -300, and -300ER series airplanes. That NPRM was published in 
the Federal Register on May 26, 2006 (71 FR 30338). That NPRM proposed 
to require replacement of the gimbal plates of the left and right 
outboard trailing edge flaps with improved gimbal plates and other 
specified actions.

Comments

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

Support for the NPRM

    Boeing, British Airways, American Airlines, and the Air Transport 
Association (ATA) support the intent of the NPRM.

Request To Use Existing Gimbal Plates

    Delta Airlines requests that we either have Boeing revise Alert 
Service Bulletin 777-27A0073, dated March 30, 2006, or that we revise 
paragraph (f) of the NPRM to allow operators to deviate from the 
referenced service bulletin. The commenter would like to continue to 
use existing gimbal plates having part numbers (P/Ns) 113W1112-3, 
113W1112-4, 113W1212-3, and 113W1212-4. As justification, the commenter 
states the service bulletin specifies installing improved gimbal plates 
having P/Ns 113W1112-7, 113W1112-8, 113W1212-7, and 113W1212-8, but it 
does not specify to replace or remove the existing parts. The commenter 
also cites paragraph (g) of the NPRM, which allows installation of the 
existing parts if an airplane is modified in accordance with paragraph 
(f) of the NPRM.
    We do not agree to allow use of the existing gimbal plates. 
Although the existing gimbal plate part numbers are not identified 
explicitly in the service bulletin, we confirmed with Boeing that they 
are P/Ns 113W1112-3, 113W1112-4, 113W1212-3, and 113W1212-4. Further, 
the effectivity of Boeing Alert Service Bulletin 777-27A0073 identifies 
Model 777-200, -300, and -300ER series airplanes that have the existing 
gimbal plates installed and approved as part of their type design. The 
intent of the service bulletin is to replace the existing gimbal plates 
with new, improved gimbal plates having P/Ns 113W1112-7, 113W1112-8, 
113W1212-7, and 113W1212-8. These new, improved gimbal plates are 
identified clearly in the service bulletin and must be installed to 
adequately address the unsafe condition of this AD. We acknowledge that 
paragraph (g) of the NPRM is confusing in that it contains the phrase 
``* * * unless it has been modified in accordance with paragraph (f) of 
this AD.'' However, that phrase is not accurate and was inadvertently 
included in the NPRM. We have deleted that phrase from paragraph (g) of 
this AD.

Request for Clarification on Improved Gimbal Plates

    Delta Airlines requests clarification on the new, improved gimbal 
plates. The commenter states that the NPRM and Boeing Alert Service 
Bulletin 777-27A0073, dated March 30, 2006, do not appear to be in 
agreement regarding use of existing gimbal plate P/Ns 113W1112-3, 
113W1112-4, 113W1212-3, and 113W1212-4. The commenter also states that 
these part numbers are not referenced in the service bulletin. The 
commenter further requests that we provide more information regarding 
usage of the new, improved P/Ns 113W1112-7, 113W1112-8, 113W1212-7, and 
113W1212-8.
    We acknowledge that paragraph (g) of the NPRM has caused confusion 
regarding the existing and new, improved part numbers. As stated 
previously, we have deleted a certain phrase to clarify that the 
existing parts may no longer be installed on the affected airplanes. 
Installation of the new, improved parts is necessary to adequately 
address the unsafe condition of this AD. No further change has been 
made to this AD in this regard.

Request To Extend Compliance Time

    British Airways requests that we extend the compliance time of the 
NPRM to 30 months. The commenter states that the maintenance planning 
document schedules zonal inspections at intervals of 6,000 flight 
cycles or 1,125 days, and that the commenter currently performs these 
inspections at intervals of 750 days (corresponding to just under 25 
months). The commenter contends that the proposed compliance time could 
cause it to accomplish the gimbal replacement during minor maintenance. 
The commenter states that extending the compliance time would allow it 
to accomplish the gimbal replacement at a heavy maintenance facility.
    We do not agree with the commenter's request to extend the 
compliance time. In developing an appropriate compliance time for this 
action, we considered the safety implications, parts availability, and 
normal maintenance schedules for the timely accomplishment of the 
replacement. In consideration of these items, we have determined that a 
compliance time of 24 months will ensure an acceptable level of safety 
and allow the modifications to be done during scheduled maintenance 
intervals for most affected operators. However, under the provisions of 
paragraph (h) of this AD, we may approve requests for adjustments to 
the compliance time if data are submitted to substantiate that such an 
adjustment would provide an acceptable level of safety. We have not 
revised this AD in this regard.

Request To Revise Compliance Time to Flight Cycles

    British Airways requests that we express the compliance time in 
units of flight cycles. The commenter asserts that calendar time is an 
inappropriate unit of life control. As justification, the commenter 
states that flap operations would primarily influence the failure 
experienced. The commenter proposes 6,000 flight cycles as a more 
appropriate compliance time.
    We disagree with revising the compliance time. Although failure of 
the pivot link is primarily affected by airplane flight cycles, the 
original design of the flap system was certified to withstand such a 
failure. A design

[[Page 3717]]

deficiency exists in the gimbal plate structure within the flap system. 
This design deficiency is not fatigue related and accordingly not 
flight-cycle related. Therefore, it is appropriate to use a calendar 
time to express the compliance time. The compliance time of 24 months 
was selected to allow replacement of the gimbal plates during a routine 
maintenance visit. We have not revised this AD in this regard.

Request To Revise the Costs of Compliance

    American Airlines requests that we adjust the costs estimated in 
the NPRM. American Airlines states that it has accomplished the gimbal 
plate replacement in accordance with Boeing Alert Service Bulletin 777-
27A0073, dated March 30, 2006, on 2 of its 45 affected airplanes. 
American Airlines estimates that the cost impact for accomplishing the 
NPRM will be approximately $84,200 per airplane, or $3,789,000 for its 
entire fleet. We infer the commenter would like us to revise the Cost 
of Compliance paragraph in this AD.
    We disagree. The cost information in this AD describes only the 
direct costs of the specific actions required by this AD. Based on the 
best data available, the manufacturer provided the number of work hours 
(153) necessary to do the required actions. This number represents the 
time necessary to perform only the actions actually required by this 
AD. We recognize that, in doing the actions required by an AD, 
operators may incur incidental costs in addition to the direct costs. 
The cost analysis in AD rulemaking actions, however, typically does not 
include incidental costs such as the time required to gain access and 
close up, time necessary for planning, or time necessitated by other 
administrative actions. Those incidental costs, which may vary 
significantly among operators, are almost impossible to calculate. We 
have not changed this AD in this regard.

New Note Added to Paragraph (f)

    We have added a note to paragraph (f) of this AD informing 
operators to pay particular attention that grease or lubricant is not 
applied to the gimbal plate bolts, bushings, washers, or nuts. Yielding 
or failure of the bolts could occur due to overtorquing a lubricated 
attachment that was intended to be installed without lubricant.

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 546 airplanes of the affected design in the 
worldwide fleet. This AD affects about 145 airplanes of U.S. registry. 
The required actions take about 153 work hours per airplane, at an 
average labor rate of $80 per work hour. Required parts cost about 
$69,850 per airplane. Based on these figures, the estimated cost of the 
AD for U.S. operators is $11,903,050, or $82,090 per airplane.

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):

2007-02-23 Boeing: Amendment 39-14910. Docket No. FAA-2006-24891; 
Directorate Identifier 2006-NM-080-AD.

Effective Date

    (a) This AD becomes effective March 2, 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 Alert Service Bulletin 777-27A0073, dated March 30, 2006.

Unsafe Condition

    (d) This AD results from a broken pivot link found on the 
inboard support for the outboard trailing edge flap. We are issuing 
this AD to prevent disconnection of the drive arm from its drive 
gimbal, due to a broken pivot link on an outboard flap support, 
which could result in unexpected roll of the airplane and loss of 
control 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.

Replacement of Gimbal Plates

    (f) Within 24 months after the effective date of this AD, 
replace the gimbal plates of the left and right outboard trailing 
edge flaps with improved gimbal plates, and do the other specified 
actions before further flight after the replacement, by 
accomplishing all the actions specified in the Accomplishment 
Instructions of Boeing Alert Service Bulletin 777-27A0073, dated 
March 30, 2006.

    Note 1: Pay particular attention that grease or lubricant is not 
applied to the gimbal plate bolts, bushings, washers, or nuts. 
Yielding or failure of the bolts could occur due to

[[Page 3718]]

overtorquing a lubricated attachment that was intended to be 
installed without lubricant.

Parts Installation

    (g) As of the effective date of this AD, no person may install a 
gimbal plate, part numbers 113W1112-3, 113W1112-4, 113W1212-3, and 
113W1212-4, on any airplane.

Alternative Methods of Compliance (AMOCs)

    (h)(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, and the approval must specifically refer to this 
AD.

Material Incorporated by Reference

    (i) You must use Boeing Alert Service Bulletin 777-27A0073, 
dated March 30, 2006, 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 this 
document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for a copy of this service information. You 
may review copies at the Docket Management Facility, U.S. Department 
of Transportation, 400 Seventh Street, SW., Room PL-401, Nassif 
Building, Washington, DC; on the Internet at http://dms.dot.gov; or 
at the National Archives and Records Administration (NARA). For 
information on the availability of this material at the NARA, call 
(202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on January 17, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-1081 Filed 1-25-07; 8:45 am]
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