AD 2001-07-05

[Federal Register Volume 66, Number 69 (Tuesday, April 10, 2001)]
[Rules and Regulations]
[Pages 18523-18525]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-8612]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-157-AD; Amendment 39-12170; AD 2001-07-05]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767 Series Airplanes 
Powered by General Electric or Pratt & Whitney Engines

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 767 series airplanes powered by 
General Electric or Pratt & Whitney engines, that requires repetitive 
inspections to detect discrepancies of the aft-most fastener holes in 
the horizontal tangs of the midspar fitting of the strut, and 
corrective actions, if necessary. This AD also provides an optional 
terminating action for the repetitive inspections. These actions are 
necessary to prevent fatigue cracking in primary strut structure and 
reduced structural integrity of the strut, which could result in 
separation of the strut and engine. This action is intended to address 
the identified unsafe condition.

DATES: Effective May 15, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 15, 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: John Craycraft, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2782; 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 767 series 
airplanes powered by General Electric or Pratt & Whitney engines was 
published in the Federal Register on October 10, 2000 (65 FR 60124). 
That action proposed to require repetitive inspections to detect 
discrepancies of the aft-most fastener holes in the horizontal tangs of 
the midspar fitting of the strut, and corrective actions, if necessary. 
That action also proposed to provide for optional terminating action 
for the repetitive inspections.

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 Limit Area of Inspection or Give Credit for Previous 
Inspections

    Several commenters request that the FAA revise paragraph (a) of the 
proposed AD to limit the area of the inspections to the two aft-most 
holes of the horizontal tangs of the midspar fitting of the strut, as 
shown in Boeing Service Bulletin 767-54A0101, Revision 1, dated 
February 3, 2000, rather than requiring inspections of the four aft 
most holes. The commenters state that the two aft-most holes are the 
most susceptible to fatigue cracking because of the higher stresses in 
this area of the midspar fitting. The commenters conclude that, as long 
as the two aft-most holes are uncracked, the next two holes would be 
uncracked as well. One commenter suggests reducing the interval for the 
repetitive inspections of the two aft-most holes in lieu of expanding 
the inspection area to the four aft-most holes. Other commenters 
request that, if the FAA finds it necessary to require inspections 
beyond the area specified in the service bulletin, the initial 
inspection per paragraph (a) be deferred to 1,500 flight cycles if 
inspections of the two aft-most holes have been accomplished before the 
effective date of this AD per the service bulletin.
    The FAA partially concurs with the commenters' requests. While, in 
theory, if the two aft-most holes are not cracked, the next row of 
holes should not be cracked either, the FAA has not found this to be 
the case, as discussed in the notice of proposed rulemaking (NPRM). On 
certain Model 747 series airplanes, which have fittings and loading 
conditions similar to those found on the Model 767 series airplanes 
subject to this AD, the aft-most row of fasteners of the midspar 
fittings was not cracked, but the next row of fasteners was. Based on 
this experience, the FAA does not concur with the commenters' request 
to reduce the inspection interval in lieu of requiring inspections of 
both rows of fasteners.
    However, the FAA does concur that the initial compliance time for 
the inspection of the four aft-most fasteners can be extended for 
airplanes on which the two aft-most fasteners have been inspected per 
the service bulletin before the effective date of this AD. The FAA 
finds that, for these previously inspected airplanes only, the 
compliance time for paragraph (a) of this AD can be extended from 600 
flight hours to 1,500 flight hours. Accordingly, a new paragraph (b) 
has been added to this final rule and subsequent paragraphs have been 
reordered.

Request To Reference Revised Service Information

    One commenter questions whether the FAA will revise the proposed 
rule to reference a new revision of the service bulletin. The commenter 
points out that the proposed requirement to inspect the four aft-most 
fasteners is a difference from the service bulletin and questions 
whether the FAA will provide an alternative method of compliance (AMOC) 
for this requirement, or whether a local approved authority will

[[Page 18524]]

have to carry out the proposed extra work until a new revision of the 
service bulletin is approved.
    The FAA does not concur that any change to this final rule is 
necessary in this regard. The FAA cannot revise this final rule to 
reference a new revision of the service bulletin because the FAA has 
received no such revision. In response to the commenter's question 
about issuance of an AMOC, no AMOC is required for the requirements of 
this AD, because the requirements of an AD take precedence over the 
procedures listed in a service bulletin. No change to the final rule is 
necessary in this regard.

Request To Approve AMOC

    One commenter requests that the FAA revise the proposed rule to 
approve the use of GE RTV108 sealant as an alternative to the BMS 
sealant specified in the service bulletin. According to the commenter, 
the airplane manufacturer has approved the use of GE RTV108 sealant. 
The commenter also states that fasteners on the inboard fitting aft of 
the aft vapor barrier do not need sealant. The commenter further notes 
that it has requested that Boeing revise its service bulletin to 
reflect these changes.
    The FAA does not concur with the commenter's request to revise the 
final rule to approve the use of an alternative sealant and to specify 
that sealant does not need to be applied to certain fasteners. The 
service bulletin has not yet been revised, and FAA has not received any 
technical justification for the changes requested by the commenter. 
However, if the commenter can provide data that shows that an 
acceptable level of safety can be achieved through the methods of 
compliance it describes, the commenter may request approval of an AMOC 
in accordance with paragraph (e) of this AD. No change to the final 
rule is necessary in this regard.

Request To Revise Cost Impact Information

    One commenter states that the cost impact in the NPRM is totally 
unrealistic because it does not account for the time to gain access to 
the inspection area or to return the airplane to service.
    The FAA does not concur with what it infers is a request to revise 
the cost estimate. The FAA stated in the ``Cost Impact'' section of the 
NPRM that, ``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.'' The FAA's position on this matter has not changed since 
issuance of the NPRM. Thus, no change to the final rule is necessary in 
this regard.

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 636 Model 767 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 235 
airplanes of U.S. registry will be affected by this AD.
    It will take approximately 1 work hour per airplane to accomplish 
the required detailed visual inspection, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of this 
inspection on U.S. operators is estimated to be $14,100, or $60 per 
airplane, per inspection cycle.
    It will take approximately 3 work hours per airplane to accomplish 
the required eddy current inspection, at an average labor rate of $60 
per work hour. Based on these figures, the cost impact of this 
inspection on U.S. operators is estimated to be $42,300, or $180 per 
airplane, per inspection cycle.
    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 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:

2001-07-05  Boeing: Amendment 39-12170. Docket 2000-NM-157-AD.

    Applicability: Model 767 series airplanes, certificated in any 
category, as listed in Boeing Service Bulletin 767-54A0101, Revision 
1, dated February 3, 2000.

    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 (e) 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 fatigue cracking in primary strut structure and 
reduced structural integrity of the strut, which could result in

[[Page 18525]]

separation of the strut and engine, accomplish the following:

Repetitive Inspections

    (a) Except as provided by paragraph (b) of this AD, before the 
accumulation of 10,000 total flight cycles, or within 600 flight 
cycles after the effective date of this AD, whichever occurs later: 
Accomplish the inspections required by paragraph (a)(1) or (a)(2) of 
this AD, as applicable.
    (1) Perform a detailed visual inspection of the four aft-most 
fastener holes in the horizontal tangs of the midspar fitting of the 
strut to detect cracking, in accordance with Part 1, ``Detailed 
Visual Inspection,'' of the Accomplishment Instructions of Boeing 
Service Bulletin 767-54A0101, Revision 1, dated February 3, 2000. If 
no cracking is detected, repeat the inspection thereafter at the 
applicable intervals specified in Table 1, ``Reinspection Intervals 
for Part 1--Detailed Visual Inspection'' included in Figure 1 of the 
service bulletin.

    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.''

    (2) Perform a high frequency eddy current inspection of the four 
aft-most fastener holes in the horizontal tangs of the midspar 
fitting of the strut to detect discrepancies (cracking, incorrect 
fastener hole diameter), in accordance with Part 2, ``High Frequency 
Eddy Current (HFEC) Inspection,'' of the Accomplishment Instructions 
of the service bulletin. Accomplish the requirements specified in 
paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as applicable; and 
repeat the inspection thereafter at the applicable intervals 
specified in Table 2, ``Reinspection Intervals for Part 2--HFEC 
Inspection'' included in Figure 1 of the service bulletin.
    (i) If no cracking is detected and the fastener hole diameter is 
less than or equal to 0.5322 inch, rework the hole in accordance 
with Part 3 of the Accomplishment Instructions of the service 
bulletin.
    (ii) If no cracking is detected and the fastener hole diameter 
is greater than 0.5322 inch, accomplish the requirements specified 
in either paragraph (c)(1) or (c)(2) of this AD.
    (b) For airplanes on which the two aft-most fasteners have been 
inspected in accordance with Boeing Service Bulletin 767-54A0101, 
Revision 1, dated February 3, 2000, prior to the effective date of 
this AD: Perform the initial inspection of the four aft-most 
fasteners in accordance with paragraph (a) of this AD before the 
accumulation of 10,000 total flight cycles, or within 1,500 flight 
cycles after the effective date of this AD, whichever occurs later.

Corrective Actions

    (c) If any cracking is detected after accomplishment of any 
inspection required by paragraph (a) of this AD, before further 
flight, accomplish the requirements specified in either paragraph 
(c)(1) or (c)(2) of this AD.
    (1) Accomplish the terminating action specified in Part 4 of the 
Accomplishment Instructions of Boeing Service Bulletin 767-54A0101, 
Revision 1, dated February 3, 2000. Accomplishment of this paragraph 
terminates the requirements of this AD.
    (2) Replace the midspar fitting of the strut with a serviceable 
part, or repair in accordance with a method approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA. Repeat the 
applicable inspection thereafter at the applicable time specified in 
paragraph (a)(1) or (a)(2) of this AD.
    (d) If any discrepancies (cracking, incorrect fastener hole 
diameter) are detected during any inspection required by paragraph 
(a) of this AD, for which the service bulletin specifies that the 
manufacturer may be contacted for disposition of those repair 
conditions: Before further flight, accomplish the corrective actions 
(including fastener hole rework and/or midspar fitting replacement) 
in accordance with a method approved by the Manager, Seattle ACO; or 
in accordance with data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the Manager, Seattle ACO, 
to make such findings. For a method to be approved by the Manager, 
Seattle ACO, as required by this paragraph, the Manager's approval 
letter must specifically reference this AD.

Alternative Methods of Compliance

    (e) 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 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

    (f) 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

    (g) Except as provided by paragraphs (c)(2) and (d) of this AD, 
the actions shall be done in accordance with Boeing Service Bulletin 
767-54A0101, Revision 1, dated February 3, 2000. 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

    (h) This amendment becomes effective on May 15, 2001.

    Issued in Renton, Washington, on April 2, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-8612 Filed 4-9-01; 8:45 am]
BILLING CODE 4910-13-P