[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 [www.gpo.gov]
[FR Doc No: 01-9662]
[[Page 20387]]
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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:
[email protected]. 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:
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.
For each issue, state what specific change to the AD is
being requested.
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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