Airworthiness Directives; Boeing Model 767 Series Airplanes

[Federal Register Volume 64, Number 226 (Wednesday, November 24, 1999)]
[Proposed Rules]
[Pages 66119-66121]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30631]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-132-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 767 series 
airplanes. This proposal would require repetitive inspections of the 
side load underwing fitting bushings for broken sealant or bushing 
migration, and corrective action, if necessary. This proposal would 
also provide optional terminating action in lieu of repetitive 
inspections. This proposal is prompted by reports of migrated bushings 
and corrosion on the side load fittings. The actions specified by the 
proposed AD are intended to prevent corrosion in the side load 
underwing fitting, which could result in cracking and consequent 
reduced structural integrity of the wing strut.

DATES: Comments must be received by January 10, 2000.


[[Page 66120]]


ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-132-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.
    The service information referenced in the proposed rule 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.

FOR FURTHER INFORMATION CONTACT: James G. Rehrl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2783; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-132-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 99-NM-132-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of migrated bushings on the side load 
underwing fittings on Boeing Model 767 series airplanes. Where migrated 
bushings were found, several cases of corrosion of the side fitting lug 
bore were reported. Migration of the side load fitting bushing breaks 
the moisture barrier to the fitting bore, and can cause corrosion of 
the fitting bore. Bushing migration can also cause damage to the 
adjacent structure when the bushing contacts the adjacent structure as 
it migrates outward. This condition, if not corrected, could result in 
cracking and consequent reduced structural integrity of the wing strut.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 767-57-
0063, dated May 7, 1998, which describes procedures for repetitive 
detailed visual inspections of the side load underwing fitting bushings 
for broken sealant or bushing migration, and corrective action, if 
necessary. The corrective action includes reworking the side load 
fitting and installing a new bushing, if necessary. The service 
bulletin also describes optional terminating action to rework the side 
load fitting that may be accomplished in lieu of repetitive detailed 
visual inspections.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require accomplishment of 
the actions specified in the service bulletin described previously. 
This proposed AD also would provide for optional terminating action for 
the repetitive inspections.
    Operators should note that the FAA has determined that the 
repetitive inspections proposed by this AD can be allowed to continue 
in lieu of accomplishment of a terminating action. In making this 
determination, the FAA considers that, in this case, long-term 
continued operational safety will be adequately assured by 
accomplishing the repetitive inspections to detect broken sealant or 
bushing migration of the side load fitting bushing before it represents 
a hazard to the airplane.

Differences Between the Proposed Rule and the Service Bulletin

    Boeing Service Bulletin 767-57-0063, dated May 7, 1998, specifies 
that the manufacturer may be contacted for disposition of certain 
repair conditions, this proposed AD would require the repair of those 
conditions to be accomplished in accordance with a method approved by 
the FAA, 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 FAA to make 
such findings. For a repair method to be approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate, as specified in paragraph (d) of this proposed AD, the 
Manager's approval letter must specifically reference this AD.

Cost Impact

    There are approximately 663 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 312 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
4 work hours per airplane to accomplish the proposed inspection, and 
that the average labor rate is $60 per work hour. Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $74,880, or $240 per airplane, per inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted.
    Should an operator elect to accomplish the optional terminating 
action rather than continue the repetitive inspections, it would take 
approximately 12 work hours per airplane to accomplish the 
modification, at an average labor rate of $60 per work hour.
    Required parts would cost approximately $1,500 per airplane. Based 
on these figures, the cost impact of this optional terminating action 
is estimated to be $2,220 per airplane.

Regulatory Impact

    The regulations proposed herein would 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

[[Page 66121]]

12612, it is determined that this proposal would not have sufficient 
federalism implications to warrant the preparation of a Federalism 
Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ``ADDRESSES.''

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

Boeing: Docket 99-NM-132-AD.

    Applicability: Model 767 series airplanes, as listed in Boeing 
Service Bulletin 767-57-0063, dated May 7, 1998; 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 (f) 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 corrosion in the side load underwing fitting, which 
could result in cracking and consequent reduced structural integrity 
of the wing strut, accomplish the following:

Initial Inspection

    (a) Accomplish a detailed visual inspection of the side load 
underwing fitting to detect broken sealant or bushing migration, in 
accordance with Boeing Service Bulletin 767-57-0063, dated May 7, 
1998, at the later of the times specified in paragraphs (a)(1) and 
(a)(2) of this AD.
    (1) Within 10 years since the date of manufacture, or
    (2) Within 3000 cycles or 18 months after the effective date of 
this AD, whichever occurs first.

    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.''

Repetitive Inspections

    (b) If no broken sealant or evidence of bushing migration is 
detected, repeat the inspection required by paragraph (a) of this AD 
thereafter at intervals not to exceed 6 years.

Corrective Action

    (c) If evidence of broken sealant or bushing migration is 
detected, prior to further flight, accomplish the corrective action 
specified in paragraph (c)(1) or (c)(2) of this AD, except as 
provided by paragraph (d) of this AD.
    (1) Remove the bushing and inspect the side load fitting lug 
bore for corrosion as shown in Figure 3 of Boeing Service Bulletin 
767-57-0063, dated May 7, 1998, and rework as specified in Figure 3 
of the service bulletin.
    (2) Reseal the bushing and service the side load fitting in 
accordance with Boeing Service Bulletin 767-57-0063, dated May 7, 
1998. Within 3,000 flight cycles or 18 months, whichever occurs 
first, remove the bushing and inspect the side load fitting lug bore 
for corrosion as shown in Figure 3 of the service bulletin, and 
rework as specified in Figure 3 of the service bulletin.
    (d) For airplanes on which broken sealant or evidence of bushing 
migration is detected: During the accomplishment of the actions 
specified in paragraphs(c)(1) or (c)(2) of this AD, if damage to the 
lug bore or fitting is found that is outside the limits specified in 
Boeing Service Bulletin 767-57-0063, dated May 7, 1998; prior to 
further flight, repair in accordance with a method approved by the 
Manager, Seattle Aircraft 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 
FAA to make such findings. For a repair method to be approved by the 
Manager, Seattle ACO, as required by this AD, the Manager's approval 
letter must specifically reference this AD.

Optional Terminating Action

    (e) Accomplishment of rework of the side load fitting in 
accordance with Figure 1 or Figure 3 of Boeing Service Bulletin 767-
57-0063, dated May 7, 1998, constitutes terminating action for the 
requirements of this AD.

Alternative Methods of Compliance

    (f) 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 Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. 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

    (g) 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.

    Issued in Renton, Washington, on November 18, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-30631 Filed 11-23-99; 8:45 am]
BILLING CODE 4910-13-U