AD 2000-11-11

[Federal Register Volume 65, Number 108 (Monday, June 5, 2000)]
[Rules and Regulations]
[Pages 35563-35566]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-13565]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-307-AD; Amendment 39-11759; AD 2000-11-11]
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 one-time inspections to detect cracking of the aft wheel well 
bulkhead, corrective actions, if necessary, and modification of the aft 
wheel well bulkhead. For certain airplanes, this AD also requires a 
one-time visual inspection to detect excess sealant covering the outer 
flange of the side fitting and lower chord and splice area of the aft 
wheel well bulkhead, and corrective actions, if necessary. This 
amendment is prompted by a report indicating that numerous fatigue 
cracks were found in the aft wheel well bulkhead. The actions specified 
by this AD are intended to prevent fatigue cracking of the aft wheel 
well bulkhead, which could result in rapid in-flight decompression of 
the airplane.

DATES: Effective July 10, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 10, 2000.

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, Transport Airplane Directorate, 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 November 26, 
1999 (64 FR 66426). That action proposed to require one-time 
inspections to detect cracking of the aft wheel well bulkhead, and 
corrective actions, if necessary. That action also proposed to require 
modification of the aft wheel well bulkhead. For certain airplanes, 
that action also proposed to require a one-time visual inspection to 
detect excess sealant covering the outer flange of the side fitting and 
lower chord and splice area of the aft wheel well bulkhead, and 
corrective actions, if necessary.

Explanation of Relevant Service Information

    Since the issuance of the notice of proposed rulemaking (NPRM), the 
FAA has reviewed and approved Boeing Service Bulletin 777-53A0015, 
Revision 1, dated March 2, 2000. (The original issue of the service 
bulletin, dated June 17, 1999, is referenced in the NPRM as the 
appropriate source of service information for accomplishment of the 
proposed actions.) The procedures described in Revision 1 of the 
service bulletin are similar to those in the original issue, and 
Revision 1 adds no new airplanes to the effectivity listing. Therefore, 
paragraphs (a), (b), and (d) of

[[Page 35564]]

this final rule have been revised to reference Revision 1 as the 
appropriate source of service information for accomplishment of the 
actions required by those paragraphs. In addition, a new ``NOTE 3'' has 
been added to this final rule to specify that actions accomplished 
prior to the effective date of this AD in accordance with Boeing Alert 
Service Bulletin 777-53A0015, dated June 17, 1999, are considered 
acceptable for compliance with this AD.

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.

Fleet Not Affected

    On behalf of one of its members, the Air Transport Association of 
America (ATA) comments that none of the airplanes operated by that 
member would be affected by the proposal. The ATA offers no further 
comment and makes no request.

Request To Revise Compliance Time: Paragraph (a)(2)

    One commenter requests that the FAA revise paragraph (a)(2) of the 
proposed rule to specify that removal of excess sealant from the aft 
wheel well bulkhead area is not required until accomplishment of the 
inspections specified in paragraph (b) of the proposed rule. [Paragraph 
(a)(2) of the proposed rule states that, if any excess sealant is 
found, it must be removed from the aft wheel well bulkhead area prior 
to further flight.] The commenter points out that the excess sealant is 
of concern because it can impede the inspections to detect fatigue 
cracking that are specified in paragraph (b) of the proposed rule, but 
the excess sealant on its own poses no threat to the continued safe 
operation of an airplane.
    The FAA does not concur with the commenter's request. The 
compliance time is the same for the requirements of both paragraphs (a) 
and (b). Therefore, the FAA expects the requirements of these 
paragraphs will be accomplished at the same time. No change to the 
final rule is necessary in this regard.

Request To Remove Airplane from Effectivity

    One commenter requests that the FAA revise the applicability of the 
proposed rule to delete the airplane having line number 1. The 
commenter states that this airplane is owned by the manufacturer and is 
operated in accordance with an experimental airworthiness certificate. 
The commenter asserts that this airplane does not accumulate enough 
flight cycles to develop significant fatigue cracking of the aft wheel 
well bulkhead. The commenter also states that, if the airplane is sold, 
the manufacturer will incorporate a design change equivalent to the 
requirements of this AD prior to delivery. The commenter claims that 
inclusion of the subject airplane in the applicability of this AD will 
``introduce additional unnecessary complications in obtaining 
certification of this airplane.''
    The FAA does not concur with the commenter's request. Though the 
airplane is operated in accordance with an experimental airworthiness 
certificate, the airplane is still subject to the unsafe condition 
addressed in this AD. Based on the current utilization of the airplane, 
the FAA acknowledges that it may be some time before the airplane will 
be required to be in compliance with this AD. However, eventually, the 
airplane must be inspected and modified in accordance with this AD, or 
modified with a design change that will provide an equivalent level of 
safety. Any design change that the manufacturer develops in lieu of the 
actions required by this AD must be approved as an alternative method 
of compliance in accordance with paragraph (e) of this AD. No change to 
the final rule is necessary in this regard.

Request To Revise Compliance Time: Paragraph (d)

    One commenter requests that the compliance time stated for removal 
of excess sealant specified in paragraph (d) of the proposed rule be 
revised from ``prior to further flight'' to ``prior to the threshold 
specified for fatigue inspections in Section 9 of the 777 Maintenance 
Planning Document [MPD]. . . .'' The commenter states that the removal 
of the excess sealant in the area described in paragraph (d) of the 
proposed rule is intended to allow the fatigue inspections specified in 
Section 9 of the MPD to be properly conducted. The commenter states 
that the paragraph, as worded in the proposed rule, ``can be 
interpreted to mean that the sealant must be removed to facilitate 
fatigue inspection of these areas at 11,000 flights.'' Further, the 
commenter states, ``There is no data to suggest that these areas would 
be subject to significant fatigue cracking earlier than the threshold 
specified in the MPD (currently 30,000 flights for all Structures 
items).''
    The FAA does not concur with the commenter's request. Excess 
sealant may impede detection of unexpected damage during general visual 
inspections performed as part of routine maintenance. Thus, the FAA 
finds it is necessary to require the sealant to be removed prior to 
further flight after accomplishment of the modification in accordance 
with paragraph (b) of this AD. 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 109 Boeing Model 777-200 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 
35 airplanes of U.S. registry will be affected by this AD.
    For all airplanes, it will take approximately 2 work hours per 
airplane to accomplish the required general visual and HFEC inspections 
at an average labor rate of $60 per work hour. Based on these figures, 
the cost impact of these inspections on U.S. operators is estimated to 
be $4,200, or $120 per airplane.
    For all airplanes, it will take approximately 28 work hours per 
airplane to accomplish the required modification at an average labor 
rate of $60 per work hour. Required parts will cost approximately 
$6,013 per airplane. Based on these figures, the cost impact of the 
modification on U.S. operators is estimated to be $269,255, or $7,693 
per airplane.
    For certain airplanes, it will take 3 work hours per airplane to 
accomplish the inspection to detect excess sealant 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 $180 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 were not adopted.

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

[[Page 35565]]

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:

2000-11-11  Boeing: Amendment 39-11759. Docket 99-NM-307-AD.

    Applicability: Model 777-200 series airplanes having line 
numbers 1 through 144; 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 (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 of the aft wheel well bulkhead, 
which could result in rapid in-flight decompression of the airplane, 
accomplish the following:

General Visual Inspection

    (a) For Group 1 airplanes, as identified in Boeing Service 
Bulletin 777-53A0015, Revision 1, dated March 2, 2000: Prior to the 
accumulation of 11,000 total flight cycles, or within 4,000 flight 
cycles after the effective date of this AD, whichever occurs later, 
perform a one-time general visual inspection to detect excess 
sealant covering the outer flange of the side fitting and lower 
chord and splice of the aft wheel well bulkhead, in accordance with 
Part I of the Accomplishment Instructions of the service bulletin.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or drop-light, and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''


    Note 3: Inspections and modifications accomplished prior to the 
effective date of this AD in accordance with Boeing Alert Service 
Bulletin 777-53A0015, dated June 17, 1999, are considered acceptable 
for compliance with paragraphs (a), (b), and (d) of this AD.

    (1) If no excess sealant is detected, no further action is 
required by this paragraph.
    (2) If any excess sealant is detected, prior to further flight, 
remove the excess sealant from the aft wheel well bulkhead area in 
accordance with the service bulletin.

Inspections/Modification

    (b) For Groups 1 and 2 airplanes, as identified in Boeing 
Service Bulletin 777-53A0015, Revision 1, dated March 2, 2000: Prior 
to the accumulation of 11,000 total flight cycles, or within 4,000 
flight cycles after the effective date of this AD, whichever occurs 
later, perform a one-time general visual inspection to detect 
cracking of the adjacent structure of the aft wheel well bulkhead 
and perform a one-time high frequency eddy current (HFEC) inspection 
to detect cracking of the fastener holes in the web, side fitting, 
and outer chord of the aft wheel well bulkhead, in accordance with 
Part II of the Accomplishment Instructions of the service bulletin.
    (1) If no cracking is detected during the general visual and 
HFEC inspections, prior to further flight, modify the aft wheel well 
bulkhead (including cold working; replacing the fairing support 
bracket and splice plates with revised fairing support brackets and 
splice plates; and installing new web doublers and, if necessary, 
shims), in accordance with Part II of the Accomplishment 
Instructions of the service bulletin.
    (2) If any cracking is detected during the general visual 
inspection, prior to further flight, accomplish the requirements of 
paragraph (c) of this AD.
    (3) If any cracking is detected during the one-time HFEC 
inspection, prior to further flight, remove additional fasteners, 
and perform a second HFEC inspection to detect cracking of the 
fastener holes, in accordance with Part II of the Accomplishment 
Instructions of the service bulletin.
    (i) If no cracking is detected during the second HFEC 
inspection, prior to further flight, oversize all the holes to the 
diameter specified in the service bulletin, and perform a third HFEC 
inspection to detect cracking of the fastener holes, in accordance 
with Part II of the Accomplishment Instructions of the service 
bulletin.
    (A) If no cracking is detected during the third HFEC inspection, 
prior to further flight, replace the fasteners with new fasteners 
and modify the aft wheel well bulkhead (including cold working; 
replacing the fairing support bracket and splice plates with revised 
fairing support brackets and splice plates; and installing new web 
doublers and, if necessary, shims), in accordance with Part II of 
the Accomplishment Instructions of the service bulletin.
    (B) If any cracking is detected during the third HFEC 
inspection, prior to further flight, accomplish the requirements of 
paragraph (c) of this AD.
    (ii) If any cracking is detected during the second HFEC 
inspection, prior to further flight, accomplish the requirements of 
paragraph (c) of this AD.

Repair

    (c) For airplanes on which cracking has been detected during any 
inspection required by paragraph (b)(2), (b)(3)(i)(B), or (b)(3)(ii) 
of this AD, prior to further flight, repair in accordance with a 
method approved by the Manager, Seattle Airplane Certification 
Office (ACO), FAA, Transport Airplane Directorate; 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 repair method to be approved by the Manager, Seattle 
ACO, as required by this paragraph, the Manager's approval letter 
must specifically reference this AD.

Removal of Excess Sealant

    (d) For Group 1 airplanes, as identified in Boeing Service 
Bulletin 777-53A0015, Revision 1, dated March 2, 2000, on which 
excess sealant was detected and removed in accordance with paragraph 
(a) of this AD: Prior to further flight following the accomplishment 
of the modification required by paragraph (b) of this AD, remove any 
excess sealant in the remaining area of the lower lobe of the aft 
wheel well bulkhead between stringers S-27L and S-27R, in accordance 
with the service bulletin.

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

[[Page 35566]]

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

    (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 paragraph (c) of this AD, the actions 
shall be done in accordance with Boeing Service Bulletin 777-
53A0015, Revision 1, dated March 2, 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.
    (h) This amendment becomes effective on July 10, 2000.

    Issued in Renton, Washington, on May 24, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-13565 Filed 6-2-00; 8:45 am]
BILLING CODE 4910-13-U