[Federal Register Volume 64, Number 120 (Wednesday, June 23, 1999)]
[Rules and Regulations]
[Pages 33390-33392]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-15778]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-116-AD; Amendment 39-11198; AD 99-13-05]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 777 series airplanes. This action 
requires repetitive inspections to detect cracking of the upper cutout 
and lower flange of the outboard support assembly of the flaperons on 
the wings; and corrective actions, if necessary. This amendment also 
provides an optional terminating action for the repetitive inspections. 
This amendment is prompted by results of flight testing conducted by 
the manufacturer indicating that high engine thrust conditions during 
takeoff cause excessive cyclic loads and could lead to fatigue cracking 
of the outboard support of the flaperon. The actions specified in this 
AD are intended to detect and correct such fatigue cracking, which 
could result in fracture of the flaperon support structure, loss of the 
flaperon, and consequent reduced controllability of the airplane.

DATES: Effective July 8, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 8, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before August 23, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-116-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD may be obtained from 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207. This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Stan Wood, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2772; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: Results of flight testing of the Boeing 
Model 777 series airplane indicate that high engine thrust conditions 
during takeoff cause excessive cyclic loads on the flaperon support 
structure of the flaperons on the left and right wings. Based on 
engineering analysis of the flaperon support structure, it was 
determined that due to the reduced fatigue life of the affected parts, 
fatigue cracks could develop on the outboard support of the flaperons. 
For airplanes powered by Rolls-Royce engines, it was determined that 
fatigue cracks could occur prior to the accumulation of 4,000 total 
flight cycles; and for airplanes powered by General Electric and Pratt 
& Whitney engines, fatigue cracks could occur prior to the accumulation 
of 10,000 total flight cycles. Such fatigue cracking of the outboard 
support of the flaperons, if not detected and corrected, could result 
in fracture of the flaperon support structure, loss of the flaperon, 
and consequent reduced controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
777-57A0008, dated March 25, 1999, which describes procedures for 
accomplishment of repetitive high frequency eddy current (HFEC) 
inspections to detect cracking of the upper cutout and lower flange of 
the outboard support assembly of the flaperons on the left and right 
wings; and corrective actions, if necessary. The corrective actions 
include modification of the fairings of the outboard flaperon; 
modification of the lower panels of the fixed trailing edge of the 
outboard flaperon; replacement of the existing outboard support, the 
outboard support bearing block, and the upper panel bracket of the 
fixed trailing edge of the flaperons on each wing with new components; 
and an operational test to detect fuel leakage.
    In addition, the service bulletin describes procedures for 
accomplishment of modification of the inboard aft fairing assembly of 
the flaperons to be accomplished concurrently with the modification of 
the outboard support assemblies. These procedures include modification 
of the aft fairing of the inboard support and replacement of the 
existing inboard support bearing block with a new block.
    Accomplishment of the modifications described previously eliminates 
the need for the repetitive inspections.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to detect and correct fatigue cracking of the outboard 
support assembly of the flaperons on each wing, which could result in 
fracture of the flaperon support structure, loss of the flaperon, and 
consequent reduced controllability of the airplane. This AD requires 
accomplishment of the actions specified in the service bulletin 
described previously, except as discussed below. In addition, this AD 
provides an optional terminating action for the repetitive inspections.

Differences Between This Rule and Alert Service Bulletin

    The alert service bulletin specifies that the manufacturer may be 
contacted for disposition of certain cracking conditions, in lieu of 
accomplishment of the terminating action. However, if any cracking is 
detected, this AD requires accomplishment of the terminating action 
prior to further flight.
    The alert service bulletin specifies that certain corrective 
actions required by this AD may be accomplished in accordance with the 
Airplane Maintenance Manual or an operator's ``equivalent procedure.'' 
However, this AD requires that any such actions be

[[Page 33391]]

accomplished only in accordance with the procedures specified in the 
Airplane Maintenance Manual. An ``operator's equivalent procedure'' may 
be used only if approved as an alternative method of compliance in 
accordance with the provisions of this AD.

Interim Action

    This is considered to be interim action. The FAA is currently 
considering requiring modification of the outboard and inboard support 
assemblies of the flaperons, as described in the alert service 
bulletin, which would constitute terminating action for the repetitive 
inspections required by this AD. However, the planned compliance time 
for these actions is sufficiently long so that notice and opportunity 
for prior public comment will be practicable.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications shall identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-116-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

99-13-05  Boeing:  Amendment 39-11198. Docket 99-NM-116-AD.

    Applicability: Model 777 series airplanes, as listed in Boeing 
Alert Service Bulletin 777-57A0008, dated March 25, 1999; 
certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (f) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct fatigue cracking of the outboard support 
of the flaperon, which could result in fracture of the flaperon 
support structure, loss of the flaperon, and consequent reduced 
controllability of the airplane; accomplish the following:

Repetitive Inspections

    (a) Perform high frequency eddy current (HFEC) inspections to 
detect fatigue cracking of the upper cutout and lower flange of the 
outboard support assembly of the flaperons on the left and right 
wings, in accordance with Part 1 of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 777-57A0008, dated March 25, 1999, 
at the time specified in paragraph (a)(1) or (a)(2) of this AD, as 
applicable.
    (1) For airplanes identified as Group 1 in the alert service 
bulletin: Perform HFEC inspections prior to the accumulation of 
10,000 total flight cycles, or within 225 flight cycles after the 
effective date of this AD, whichever occurs later. Repeat the 
inspections thereafter at intervals not to exceed 225 flight cycles.
    (2) For airplanes identified as Group 2 in the alert service 
bulletin: Perform HFEC inspections prior to the accumulation of 
4,000 total flight cycles, or within 70 flight cycles after the 
effective date of this AD, whichever occurs later. Repeat the 
inspections thereafter at intervals not to exceed 70 flight cycles.

Corrective Action

    (b) If any fatigue cracking is detected during any inspection 
required by paragraph (a) of this AD: Prior to further flight, 
concurrently accomplish the modifications specified in Parts 2 and 3 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
777-57A0008, dated March 25, 1999. Accomplishment of the 
modifications constitutes terminating action for the repetitive 
inspection requirements of this AD.

[[Page 33392]]

    (c) If any fatigue cracking is detected, and Boeing Alert 
Service Bulletin 777-57A0008, dated March 25, 1999, specifies that 
corrective actions may be accomplished in accordance with an 
operator's ``equivalent procedure:'' The actions must be 
accomplished in accordance with the chapter of the Boeing 777 
Airplane Maintenance Manual (AMM) specified in the alert service 
bulletin.

Optional Terminating Action

    (d) Concurrent accomplishment of the modifications specified in 
Parts 2 and 3 of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 777-57A0008, dated March 25, 1999, constitutes 
terminating action for the repetitive inspections required by this 
AD.

Spares

    (e) As of the effective date of this AD, no person shall install 
any part identified in the ``Existing Part Number'' column of 
Section 2.E. of Boeing Alert Service Bulletin 777-57A0008, dated 
March 25, 1999, on any airplane.

Alternative Methods of Compliance

    (f) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (g) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

Incorporation by Reference

    (h) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 777-57A0008, dated March 25, 1999. This 
incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    (i) This amendment becomes effective on July 8, 1999.

    Issued in Renton, Washington, on June 10, 1999.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-15778 Filed 6-22-99; 8:45 am]
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