AD Amdt-39-9783

[Federal Register Volume 61, Number 207 (Thursday, October 24, 1996)]
[Rules and Regulations]
[Pages 55080-55082]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 96-26722]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-25-AD; Amendment 39-9783; AD 96-21-06]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing 767 series airplanes, that currently 
requires inspections and various follow-on actions to detect cracking 
and corrosion of the aft trunnion of the outer cylinder of the main 
landing gear (MLG). That action also provides for the optional 
termination of the inspections by repairing the outer cylinder and 
installing new aft trunnion bushings. That AD was prompted by reports 
of failure of several MLG due to fracture of the aft trunnion outer 
cylinder. This amendment requires operators to implement the previously 
optional terminating action. The actions specified by this AD are 
intended to prevent the collapse of the MLG due to stress corrosion 
cracking of the aft trunnion of the outer cylinder.

DATES: Effective November 29, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 29, 1996.
    The incorporation by reference of certain other publications listed 
in the regulations was approved previously by the Director of the 
Federal Register as of February 16, 1996 (61 FR 3552, February 1, 
1996).

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: James G. Rehrl, Aerospace Engineer, 
Airframe Branch, ANM-120S, Seattle Aircraft Certification Office, FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2783; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 96-03-02 R1, 
amendment 39-9526 (61 FR 7694, February 29, 1996), which is applicable 
to certain Boeing Model 767 series airplanes, was published in the 
Federal Register on May 14, 1996 (61 FR 24250). The action proposed to 
supersede AD 96-03-02 R1 to continue to require various inspections and 
various follow-on actions to detect cracking and corrosion of the aft 
trunnion of the outer cylinder of the MLG. The action also proposed to 
require repair of the outer cylinder and replacement of the bushings in 
the aft trunnion and crossbolt of the MLG with new bushings.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Proposed Rule

    Two commenters support the proposal.

Request to Limit the Applicability of the AD

    One commenter, the manufacturer, requests that the applicability of 
the AD be revised to reflect line numbers 1 through 605, instead of 
line numbers 1 through 609. The manufacturer states that line numbers 
606 through 609 were reworked on the production line to incorporate the 
terminating action specified by the proposed AD.
    The FAA concurs, and the applicability of the final rule has been 
revised accordingly.

Request to Refer to the Revised CMM

    The manufacturer states that the current wording of the proposed 
rule indicates that the Component Maintenance Manual (CMM) contains 
only one acceptable configuration for certain associated procedures; 
specifically, that of plugging the aft trunnion lubrication fitting. 
The manufacturer states that the CMM has been revised since the 
issuance of the proposed rule and now includes another acceptable 
configuration. The alternative configuration entails not plugging the 
aft trunnion lubrication fitting. The manufacturer, therefore, requests 
that the proposed rule be revised to reflect the inclusion of both 
configurations in the CMM.
    The FAA concurs. The FAA considers that either of the two 
configurations specified by the CMM is an acceptable configuration, and 
has revised NOTE 4 of the final rule, accordingly.

Request to Delete 5 and \1/2\ year Compliance Time for Category 3 
Airplanes

    One commenter notes that the compliance time for repair/replacement 
for Category 3 airplanes, as specified in paragraph (e)(1) of the 
proposed rule, indicates that those actions are to be accomplished 
``prior to the accumulation of 5 and \1/2\ years since the MLG outer 
cylinders were new or last overhauled, or within 18 months after the 
effective date of the AD.'' However, the commenter points out that, 
since the age of the outer cylinders are determined from the date of 
February 16, 1996, there will never be a situation in which a Category 
3 cylinder will reach 5 and \1/2\ years of age within 18 months from 
the effective date of the final rule. Therefore, the commenter requests 
that reference to the 5 and \1/2\-year compliance time be deleted.
    The FAA concurs, and has revised paragraph (e)(1) of the final rule 
accordingly.

Request to Add Requirements for Follow-on Actions

    One commenter notes that the compliance time for repetitive 
inspections specified in paragraph (a) of the proposal requires 
inspections at intervals specified in Boeing Alert Service Bulletin 
767-32A0151, dated November 30, 1995. The commenter states that the 
proposed compliance time (of within 18 months after the effective date 
of the AD) for the terminating action required by paragraph (e) of this 
AD would permit a period of time (approximately 5 to 6 months) in which 
Category 3 airplanes would not be required to perform any inspections. 
Therefore, the commenter requests that the proposed rule be revised to 
require certain follow-on actions until the terminating action required 
by paragraph (e) of the proposed rule is accomplished.
    The FAA does not concur. Two other AD's [namely, AD 95-19-10, 
amendment 39-9372 (60 FR 47689, September 14, 1995); and AD 95-20-51, 
amendment 39-9398 (60 FR 53109, October 12, 1995)] currently exist that 
require similar inspections to detect cracking and corrosion and 
certain other follow-on actions of the aft trunnion of the outer 
cylinder of the MLG. The FAA has determined that the subject unsafe 
condition will be positively addressed by those actions in the interim 
until the terminating action of this AD is accomplished. Therefore, the 
FAA finds

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that it is unnecessary to add additional inspection requirements in 
this AD.

Request to Reference Later Revisions of Cited Service Bulletins

    The manufacturer stated that it has revised Boeing Service Bulletin 
767-32A0151 and Boeing Service Bulletin 767-32A0148 to provide further 
clarification of the inspection and modification procedures. Therefore, 
the manufacturer requests that the FAA refer to these later revisions 
as being acceptable methods of compliance with the AD.
    The FAA concurs. The FAA has reviewed and approved Revision 1 of 
both service bulletins, each dated October 10, 1996, and has revised 
the AD to cite these revisions as an additional source of service 
information.

Request to Correct Referenced AD Number

    One commenter requests that the reference to ``AD 93-03-02 R1'' in 
paragraph (h)(2) of the proposed rule be corrected to read ``AD 96-03-
02 R1.'' The FAA has noted this typographical error and has revised 
paragraph (h)(2) of the final rule accordingly.

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 605 Boeing Model 767 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 200 
airplanes of U.S. registry will be affected by this proposed AD.
    The actions that are currently required by AD 96-03-02 R1, and 
retained in this AD, take approximately 34 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact on U.S. operators of the actions 
currently required is estimated to be $408,000, or $2,040 per airplane.
    The new actions that are required by this AD action will take 
approximately 218 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts will cost approximately 
$9,510 per airplane. Based on these figures, the cost impact on U.S. 
operators of the requirements of this AD is estimated to be $4,518,000 
or $22,590 per airplane.
    The cost impact figures discussed above are 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 was not adopted.

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.
    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 removing amendment 39-9526 (61 FR 
7694, February 29, 1996), and by adding a new airworthiness directive 
(AD), amendment 39-9783, to read as follows:

96-21-06 Boeing: Amendment 39-9783. Docket 96-NM-25-AD. Supersedes 
AD 96-03-02 R1, Amendment 39-9526.

    Applicability: Model 767 series airplanes having line numbers 
001 through 605 inclusive, on which the terminating action required 
by paragraph (e) of this AD has not been accomplished; certificated 
in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 (g) 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 the collapse of the main landing gear (MLG) due to 
stress corrosion cracking of the aft trunnion of the outer cylinder, 
accomplish the following:
    (a) Perform the inspections described in paragraph III, 
Accomplishment Instructions, of Boeing Alert Service Bulletin 767-
32A0151, dated November 30, 1995, or Revision 1, dated October 10, 
1996, to detect cracking and corrosion of the aft trunnion of the 
outer cylinder of the MLG at the time specified in paragraph (a)(1), 
(a)(2), or (a)(3) of this AD, as applicable. These inspections are 
to be accomplished in accordance with Figure 1 of the alert service 
bulletin. Repeat these inspections thereafter at the intervals 
specified in that alert service bulletin. To determine the category 
in which an airplane falls, the age of the outer cylinder of the MLG 
is to be calculated as of February 16, 1996, (the effective date of 
AD 96-03-02 R1, amendment 39-9526). For airplanes on which the age 
of the right MLG differs from the age of the left MLG, an operator 
may place the airplane into a category that is the higher 
(numerically) of the two categories to ease its administrative 
burden, and to simplify the recordkeeping requirements imposed by 
this AD. Once the category into which an airplane falls is 
determined, operators must obtain approval from the Manager, Seattle 
Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate, to move that airplane into another category.

    Note 2: The broken (dash) lines used in Figure 1 of Boeing Alert 
Service Bulletin 767-32A0151, dated November 30, 1995, and Revision 
1, dated October 10, 1996, denote ``go to'' actions for findings of 
discrepancies detected during any of the inspections required by 
this AD.

    Note 3: Boeing Alert Service Bulletin 767-32A0151, dated 
November 30, 1995, and Revision 1, dated October 10, 1996, refer to

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Boeing Alert Service Bulletin 767-32A0148, dated December 21, 1995, 
and Revision 1, dated October 10, 1996, for procedures to repair the 
outer cylinder and replace the bushings in the outer cylinder of the 
MLG with new bushings.
    (1) For airplanes identified as Category 3 in paragraph I.C. of 
Boeing Alert Service Bulletin 767-32A0151, dated November 30, 1995, 
or Revision 1, dated October 10, 1996: Perform the initial 
inspections within 30 days after February 16, 1996 (the effective 
date of AD 96-03-02 R1, amendment 39-9526).
    (2) For airplanes identified as Category 2 in paragraph I.C. of 
Boeing Alert Service Bulletin 767-32A0151, dated November 30, 1995, 
or Revision 1, dated October 10, 1996: Perform the initial 
inspections within 90 days after February 16, 1996.
    (3) For airplanes identified as Category 1 in paragraph I.C. of 
Boeing Alert Service Bulletin 767-32A0151, dated November 30, 1995, 
or Revision 1, dated October 10, 1996: Perform the initial 
inspections prior to the accumulation of 2-\1/2\ years since the MLG 
outer cylinder was new or last overhauled, or within 150 days after 
February 16, 1996, whichever occurs later.
    (b) If no cracking or corrosion is detected during the 
inspections required by paragraph (a) of this AD, accomplish the 
follow-on actions described in the Boeing Alert Service Bulletin 
767-32A0151, November 30, 1995, or Revision 1, dated October 10, 
1996, at the time specified in the alert service bulletin. These 
follow-on actions are to be accomplished in accordance with that 
alert service bulletin.
    (c) If any cracking is detected during the inspections required 
by paragraph (a) of this AD, prior to further flight, replace the 
outer cylinder with a new or serviceable outer cylinder in 
accordance with Boeing Alert Service Bulletin 767-32A0151, dated 
November 30, 1995, or Revision 1, dated October 10, 1996.
    (d) If any corrosion is detected during the inspections required 
by paragraph (a) of this AD, accomplish the follow-on actions at the 
time specified in the ``Corrosion Flowchart,'' in Figure 1 of Boeing 
Alert Service Bulletin 767-32A0151, dated November 30, 1995, or 
Revision 1, dated October 10, 1996. The follow-on actions are to be 
accomplished in accordance with that alert service bulletin.
    (e) At the time specified in either paragraph (e)(1) or (e)(2), 
as applicable, repair the outer cylinder and replace the bushings in 
the aft trunnion and crossbolt of the MLG with new bushings, in 
accordance with Boeing Alert Service Bulletin 767-32A0148, dated 
December 21, 1995, or Revision 1, dated October 10, 1996. 
Accomplishment of this repair and replacement constitutes 
terminating action for this AD, and for the requirements of AD 95-
19-10, amendment 39-9372; and AD 95-20-51, amendment 39-9398.

    Note 4: Boeing Alert Service Bulletin 767-32A0148 refers to 
Component Maintenance Manual (CMM) 32-11-40 for certain procedures. 
Operators should note that this AD does not require that one or the 
other of the two configurations/actions be accomplished in order to 
terminate the requirements of this AD, AD 95-19-10, or AD 95-20-51. 
The use of either configuration specified in the CMM is considered 
to be the operator's prerogative.
    (1) For airplanes identified as Category 3 in paragraph I.C. of 
Boeing Alert Service Bulletin 767-32A0151, dated November 30, 1995, 
or Revision 1, dated October 10, 1996: Accomplish the repair and 
replacement within 18 months after the effective date of this AD.
    (2) For airplanes identified as either Category 1 or Category 2 
in paragraph I.C. of Boeing Alert Service Bulletin 767-32A0151, 
dated November 30, 1995, or Revision 1, dated October 10, 1996: 
Accomplish the repair and replacement at the time specified in 
either paragraph (e)(2)(i) or (e)(2)(ii) of this AD:
    (i) Prior to the accumulation of 5-and-\1/2\ years since the MLG 
outer cylinders were new or last overhauled, or within 18 months 
after the effective date of this AD, whichever occurs later. Or,
    (ii) Prior to the accumulation of 7 years since the MLG outer 
cylinders were new or last overhauled, provided that accomplishment 
of visual and non-destructive testing (NDT) inspections at the times 
specified in Figure 1 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 767-32A0151, dated November 30, 1995, or 
Revision 1, dated October 10, 1996, are repeated until the repair 
and replacement are accomplished.
    (f) Accomplishment of the inspection requirements of this AD (in 
accordance with Boeing Alert Service Bulletin 767-32A0151, dated 
November 30, 1995, or Revision 1, dated October 10, 1996) is 
considered acceptable for compliance with AD 95-19-10, amendment 39-
9372; and AD 95-20-51, amendment 39-9398.
    (g)(1) 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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.
    (2) Alternative methods of compliance, approved in accordance 
with AD 96-03-02, amendment 39-9497; AD 96-03-02 R1, amendment 39-
9526; AD 95-19-10, amendment 39-9372; or AD 95-20-51, amendment 39-
9398; are approved as alternative methods of compliance with this 
AD.
    (h) 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.
    (i) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 767-32A0151, dated November 30, 1995; Boeing 
Service Bulletin 767-32A0151, Revision 1, dated October 10, 1996; 
Boeing Alert Service Bulletin 767-32A0148, dated December 21, 1995, 
and Boeing Service Bulletin 767-32A0148, Revision 1, dated October 
10, 1996. The incorporation by reference of Boeing Alert Service 
Bulletin 767-32A0151, dated November 30, 1995, and Boeing Alert 
Service Bulletin 767-320148, dated December 21, 1995, was approved 
previously by the Director of the Federal Register, in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51, as of February 16, 1996 (61 
FR 3552, February 1, 1996). The incorporation by reference of Boeing 
Service Bulletin 767-32A0151, Revision 1, dated October 10, 1996, 
and Boeing Service Bulletin 767-32A0148, Revision 1, dated October 
10, 1996, 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.
    (j) This amendment becomes effective on November 29, 1996.

    Issued in Renton, Washington, on October 10, 1996.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-26722 Filed 10-23-96; 8:45 am]
BILLING CODE 4910-13-U