AD 2001-08-03

[Federal Register Volume 66, Number 78 (Monday, April 23, 2001)]
[Rules and Regulations]
[Pages 20387-20389]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-9662]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-73-AD; Amendment 39-12180; AD 2001-08-03]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200 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 777-200 series airplanes. This 
action requires repetitive inspections of the upper housing assembly of 
the forward trunnion of the main landing gear (MLG) for discrepancies 
(migrated or missing wearplates, loose or fractured attachment screws); 
and corrective action, if necessary. This action also provides for an 
optional modification of the upper housing assembly for airplanes 
without discrepant wearplates, which would end the repetitive 
inspections. This action is necessary to prevent migration or loss of 
the upper housing wearplate, which could result in loss of the MLG 
during the takeoff roll; consequent damage to the airplane structure; 
and injury to flight crew, passengers, or ground personnel. This action 
is intended to address the identified unsafe condition.

DATES: Effective May 8, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 8, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before June 22, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-73-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
<a href="/cdn-cgi/l/email-protection#ba8397dbd4d797d3dbc8d9d5d7d7dfd4cefadcdbdb94ddd5cc"><span class="__cf_email__" data-cfemail="41786c202f2c6c282033222e2c2c242f35012720206f262e37">[email&#160;protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-73-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    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, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2772; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received a report indicating 
that, during fatigue testing of a Boeing Model 777-200 series airplane, 
a wearplate of the upper housing assembly of the forward trunnion of 
the main landing gear (MLG) was found to have migrated, and the 
attachment screws were fractured. The airplane had accumulated 
approximately 32,000 flight cycles. Subsequent to that report, one 
operator reported finding loose or fractured attachment screws of the 
wearplate on three Model 777-200 series airplanes. The wearplate had 
not migrated on any of those airplanes. The airplanes had accumulated 
approximately 4,300 to 4,500 flight cycles, and 20,700 to 22,690 flight 
hours. Loose or fractured attachment screws could lead to migration or 
loss of the upper housing wearplate, which could result in loss of the 
MLG during the takeoff roll; consequent damage to the airplane 
structure; and injury to flight crew, passengers, or ground personnel.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
777-57A0011, Revision 1, dated January 25, 2001, which describes 
procedures for repetitive inspections of the upper housing assembly of 
the forward trunnion of the MLG for discrepancies (migrated or missing 
wearplates, loose or fractured attachment screws), and corrective 
action (modification) if any discrepancies are found. The modification 
includes, but is not limited to, replacement of the lower housing fuse 
pins if the wearplates are fully migrated or missing; replacement of 
the upper and lower housing assemblies, and replacement of the 
wearplate if missing or damaged. Doing the modification eliminates the 
need for the repetitive inspections. The service bulletin references 
certain Boeing 777 Airplane Maintenance Manuals as the appropriate 
sources for accomplishment of the modification. Accomplishment of the 
actions specified in the service bulletin is intended to adequately 
address the identified unsafe condition.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Model 777-200 series airplanes of the same 
type design, this AD is being issued to prevent migration or loss of 
the upper housing wearplate, which could result in loss of the MLG 
during takeoff roll; consequent damage to the airplane structure; and 
injury to flight crew, passengers, or ground personnel. This AD 
requires repetitive inspections of the upper housing assembly of the 
forward trunnion of the MLG for discrepancies (migrated or missing 
wearplates, loose or fractured attachment screws); and corrective 
action, if necessary. This AD also provides for an optional 
modification of the upper housing assembly for airplanes without 
discrepant wearplates, which would end the repetitive inspections. The 
actions are required to be accomplished per the service bulletin 
described previously, except as discussed below.

Difference Between Alert Service Bulletin and This AD

    Although the service bulletin specifies accomplishment of 
inspections, the FAA finds that ``detailed visual inspection'' is the 
appropriate terminology for the inspections described in the service 
bulletin. A definition of a detailed visual inspection is included in 
Note 2 of this AD.

Interim Action

    This is interim action. The service bulletin recommends doing the 
modification of the upper housing assembly of the forward trunnion 
within 6 years since date of delivery of the airplane or within 24 
months after the date of the service bulletin, whichever is later. This 
AD provides for the modification as optional. The FAA is currently 
considering requiring the modification, which is described in the 
service bulletin and which would end the repetitive inspections 
required by this AD action. However, the planned compliance time for 
the replacement is sufficiently long so that notice and

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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.
    Submit comments using the following format:
    <bullet> Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    <bullet> For each issue, state what specific change to the AD is 
being requested.
    <bullet> Include justification (e.g., reasons or data) for each 
request.
    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 2001-NM-73-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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:

2001-08-03  Boeing: Amendment 39-12180. Docket 2001-NM-73-AD.

    Applicability: Model 777-200 series airplanes, as listed in 
Boeing Alert Service Bulletin 777-57A0011, Revision 1, dated January 
25, 2001, 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 (c) 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 prevent migration or loss of the wearplate of the upper 
housing assembly of the forward trunnion of the main landing gear 
(MLG), which could result in loss of the MLG during the takeoff 
roll; consequent damage to the airplane structure; and injury to 
flight crew, passengers, or ground personnel; accomplish the 
following:

Repetitive Inspections/Corrective Action

    (a) Within 50 flight cycles after the effective date of this AD: 
Do a detailed visual inspection of the upper housing assembly of the 
forward trunnion of the MLG for discrepancies (migrated or missing 
wearplates, loose or fractured attachment screws), per Part 1 
``Inspection'' of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 777-57A0011, Revision 1, dated January 25, 2001.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (1) If no wearplate migration or loose or fractured attachment 
screw is found: Repeat the inspection no later than every 100 flight 
cycles, until paragraph (b) of this AD has been done.
    (2) If loose or fractured attachment screws are found but no 
wearplate migration is found: Repeat the inspection no later than 
every 50 flight cycles, until paragraph (b) of this AD has been 
done.
    (3) If the wearplate is partially migrated, before further 
flight, do the modification specified in paragraph (b) of this AD.
    (4) If the wearplate is fully migrated or missing, before 
further flight, replace the fuse pins of the lower housing assembly 
per the service bulletin, and do the modification specified in 
paragraph (b) of this AD.

Optional Terminating Modification

    (b) Do the modification of the upper housing assembly per Part 2 
``Modification'' of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 777-57A0011, Revision 1, dated January 25, 2001. 
Doing this modification ends the repetitive inspections required by 
this AD.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be

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used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA. 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 3: 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

    (d) Special flight permits may be issued in accordance with 
Secs. 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

    (e) The actions shall be done per Boeing Alert Service Bulletin 
777-57A0011, Revision 1, dated January 25, 2001. 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.

Effective Date

    (f) This amendment becomes effective on May 8, 2001.

    Issued in Renton, Washington, on April 11, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-9662 Filed 4-20-01; 8:45 am]
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