AD 2001-09-02

[Federal Register Volume 66, Number 85 (Wednesday, May 2, 2001)]
[Rules and Regulations]
[Pages 21851-21853]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-10465]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-147-AD; Amendment 39-12207; AD 2001-09-02]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 777-200 series airplanes, that 
requires replacement of certain existing bushings of the aft trunnion 
of the outer cylinder of the main landing gear (MLG) with new bushings, 
and replacement of grease in an undercut on the aft trunnion, if 
necessary. The actions specified by this AD are intended to prevent 
stress corrosion cracking and consequent fracture of the aft trunnion 
of the outer cylinder of the MLG, which could result in collapse of the 
MLG. This action is intended to address the identified unsafe 
condition.

DATES: Effective June 6, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 6, 2001.

ADDRESSES: 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 Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 777-200 
series airplanes was published in the Federal Register on December 29, 
2000 (65 FR 82959). That action proposed to require replacement of 
certain existing bushings of the aft trunnion of the outer cylinder of 
the main landing gear (MLG) with new bushings, and replacement of 
grease in an undercut on the aft trunnion, if necessary.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Delete Airplane With Line Number (L/N) 1

    One commenter requests that the Boeing Model 777 series airplane 
having L/N 1 be removed from the applicability section of the proposed 
rule. The commenter states that the main landing gear on that airplane 
was reworked prior to airplane delivery, and the outer cylinders with 
the final configuration of the aft trunnion were installed. The 
commenter adds that this rework was done at the manufacturer per Boeing 
Production Revision Record 61571, part G95. Such rework meets the 
intent of Boeing Service Bulletin 777-32-0003, dated October 9, 1997, 
which was specified in the applicability section of the proposed rule.
    The FAA concurs with the commenter. The FAA has determined that 
this airplane was retained by the manufacturer until delivery to an 
operator at the end of the year 2000. The following changes have been 
made to the final rule: The applicability and cost impact sections have 
been revised accordingly; paragraph (a)(3) of the final rule has been 
revised to remove the reference to the airplane having L/N 1; and Note 
3, which specified, ``For the purposes of this AD, the airplane having 
L/N 1 is considered to have the configuration of a Group 1 airplane,'' 
has been removed.

Revised Service Information

    The same commenter states that, subsequent to issuance of the 
proposed rule, Boeing Alert Service Bulletin 777-32A0025, Revision 1, 
dated March 8, 2001, was submitted to the FAA for approval. (The 
original issue of the

[[Page 21852]]

service bulletin was referenced in the proposal as the appropriate 
source of service information for accomplishment of the specified 
actions.) The commenter adds that the revised bulletin contains 
additional inspection requirements for operators that used a specific 
corrosion-inhibiting compound when incorporating the referenced service 
bulletin. The commenter notes that when the final rule is released it 
should reference the revised service bulletin.
    The FAA concurs with the commenter. Since the issuance of the 
proposed rule, the FAA has approved Revision 1 of the service bulletin. 
The service bulletin was revised in order to delete a certain 
corrosion-inhibiting compound specified in the original issue that, in 
certain conditions, has been found to promote corrosion. Documentation 
received from the manufacturer shows that compound was used on only 3 
of the 25 airplanes affected by this final rule, and those airplanes 
are scheduled to be reworked using the revised service bulletin. The 
final rule has been revised to require accomplishment of the specified 
actions per Revision 1 only. A new Note 3 has been added to the final 
rule to give credit for airplanes that applied the correct corrosion-
inhibiting compound per the original service bulletin.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 25 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 11 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 36 work 
hours per airplane to accomplish the required actions, and that the 
average labor rate is $60 per work hour. Required parts will cost 
approximately $13,228 per airplane. Based on these figures, the cost 
impact of the AD on U.S. operators is estimated to be $169,268, or 
$15,388 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

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.
    For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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:

2001-09-02  Boeing: Amendment 39-12207. Docket 2000-NM-147-AD.

    Applicability: Model 777-200 series airplanes; line numbers (L/
N) 2 through 29 inclusive, except L/N's 10, 14, and 18; certificated 
in any category; except those on which the outer cylinder of the 
main landing gear (MLG) has been replaced in accordance with Boeing 
Service Bulletin 777-32-0003, dated October 9, 1997.

    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 stress corrosion cracking and consequent fracture of 
the aft trunnion of the outer cylinder of the MLG, which could 
result in collapse of the MLG, accomplish the following:

Replacement of Bushings

    (a) Within 5 years and 300 days since date of manufacture of the 
airplane, or within 1 year after the effective date of this AD, 
whichever occurs later, replace bushings in the aft trunnion of the 
outer cylinder with new bushings by doing paragraphs (a)(1), (a)(2), 
(a)(3), and (a)(4) of this AD; as applicable; in accordance with 
Boeing Alert Service Bulletin 777-32A0025, Revision 1, dated March 
8, 2001.
    (1) Remove bushings in the aft trunnion of the outer cylinder of 
the MLG.
    (2) Perform a one-time detailed visual inspection of the aft 
trunnion area for corrosion or other damage.
    (3) For airplanes listed in Group 1 of the service bulletin: 
Replace grease in the undercut of the aft trunnion with corrosion-
inhibiting compound.
    (4) Install new bushings with corrosion-inhibiting compound.

    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.''

Corrective Action

    (b) If any corrosion or other damage is found during the 
inspection required by paragraph (a)(2) of this AD: Prior to further 
flight, repair in accordance with Boeing Alert Service Bulletin 777-
32A0025, Revision 1, dated March 8, 2001; except, where the service 
bulletin specifies to contact Boeing for instructions, prior to 
further flight, repair in accordance with a method approved by the 
Manager, Seattle Aircraft Certification

[[Page 21853]]

Office (ACO), FAA; or in accordance with data meeting the type 
certification basis of the airplane approved by a Boeing Company 
Designated Engineering Representative (DER) who has been authorized 
by the Manager, Seattle ACO, to make such findings. For a repair 
method to be approved by the Manager, Seattle ACO, as required by 
this paragraph, the approval letter must specifically reference this 
AD.

    Note 3: Prior accomplishment of paragraphs (a) and (b) of this 
AD, as specified in Boeing Alert Service Bulletin 777-32A0025, dated 
April 6, 2000; using BMS 3-27 or Cor-Ban 27L corrosion-inhibiting 
compound; is acceptable for compliance with the applicable actions 
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 
used if approved by the Manager, Seattle ACO. 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 4: 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 
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

    (e) Except as provided by paragraph (b) of this AD: The actions 
shall be done in accordance with Boeing Alert Service Bulletin 777-
32A0025, Revision 1, dated March 8, 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 June 6, 2001.

    Issued in Renton, Washington, on April 20, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-10465 Filed 5-1-01; 8:45 am]
BILLING CODE 4910-13-U