[Federal Register Volume 64, Number 233 (Monday, December 6, 1999)]
[Proposed Rules]
[Pages 68058-68060]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-31476]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-182-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 to detect 
fatigue cracking of the pitch load fittings of the wing front spar, and 
rework, if necessary. This proposal is prompted by a structural fatigue 
analysis that shows that the operational loads of the nacelle are 
higher than the loads used during initial design of the Model 767. The 
actions specified by the proposed AD are intended to detect and correct 
fatigue cracking in the pitch load fittings of the wing front spar, 
which could result in reduced structural integrity of the strut.

DATES: Comments must be received by January 20, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-182-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-182-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-182-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that structural fatigue 
analysis on the Boeing Model 767 series airplane shows that the 
operational loads of the nacelle are higher than the loads used during 
initial design of the Boeing Model 767 series airplane. Higher 
operational loads could lead to fatigue cracking in the pitch load 
fittings of the wing front spar initiating earlier than expected. 
Structural assessment indicated that certain design changes would be 
needed on the strut-to-wing structure of the airplane to ensure that 
fatigue cracking would not occur during the Model 767 design service 
objective of 20 years or 50,000 flight cycles. Fatigue cracking of the 
pitch load fittings of the wing front spar, if not corrected, could 
result in reduced structural integrity of the strut.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 767-57-
0053, Revision 2, dated September 23, 1999, which describes procedures 
for repetitive inspections to detect cracking of the pitch load 
fittings of the wing front spar, and rework, if necessary. The service 
bulletin describes procedures for two different methods for 
accomplishing an inspection. One method involves performing repetitive 
ultrasonic and eddy current inspections to detect cracking of the pitch 
load fittings. In lieu of that method, the service bulletin describes 
another inspection method that involves removing the upper link and 
performing a high frequency eddy current inspection to detect cracking 
of the pitch load fittings, and a detailed visual inspection to detect 
damage or corrosion of the inner and outer face pad-up areas of the 
pitch load fittings and to determine if the pad-up areas are parallel. 
The procedures for rework described in the service bulletin include 
reworking the inner or outer face of the pitch load fitting, reworking 
the lugs of the pitch load fittings, and installing new bushings. (The 
service bulletin describes two alternatives for installing the 
bushings.)

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below.

Differences Between This Proposed AD and the Service Bulletin

    Operators should note that, although the service bulletin 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

[[Page 68059]]

who has been authorized by the FAA to make such findings.

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 
10 work hours per airplane to accomplish the proposed inspections, and 
that the average labor rate is $60 per work hour. Based on these 
figures, the cost impact of the proposed inspections on U.S. operators 
is estimated to be $187,200, or $600 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.

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 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-182-AD.

    Applicability: Model 767 series airplanes, line numbers 1 
through 663 inclusive, 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 detect fatigue cracks in the pitch load fittings of the wing 
front spar, which could result in reduced structural integrity of 
the strut, accomplish the following:
    (a) Accomplish the requirements of either paragraph (b) or (c) 
of this AD at the later of the times specified in paragraphs (a)(1) 
and (a)(2) of this AD.
    (1) Prior to the initial inspection threshold specified in 
Figure 1, Table 1.1 of Boeing Service Bulletin 767-57-0053, Revision 
2, dated September 23, 1999.
    (2) Within 3,000 flight cycles or 18 months after the effective 
date of this AD, whichever occurs first.

    Note 2: Inspections and repairs accomplished prior to the 
effective date of this AD in accordance with Boeing Service Bulletin 
767-57-0053, dated June 27, 1996; or Revision 1, dated October 31, 
1996; are considered acceptable for compliance with the applicable 
action specified in this amendment.

Option 1: Ultrasonic and Eddy Current Inspections

    (b) Perform ultrasonic and eddy current inspections to detect 
cracks of the pitch load fittings of the wing front spar, in 
accordance with Boeing Service Bulletin 767-57-0053, Revision 2, 
dated September 23, 1999.
    (1) If no crack is detected, repeat the inspections thereafter 
at the interval specified in Table 1.2 of Figure 1 of the service 
bulletin.
    (2) If any crack is detected, prior to further flight, remove 
the upper link and the pitch load fitting bushings, and accomplish 
both paragraphs (b)(2)(i) and (b)(2)(ii) of this AD.
    (i) Perform a detailed visual inspection of the inner and outer 
face pad-up areas of the pitch load fittings to detect damage or 
corrosion and to determine if the pad-up areas are parallel, in 
accordance with the service bulletin. Except as provided by 
paragraph (f) of this AD, if any damage, corrosion, or non-
parallelism is detected, prior to further flight, rework the inner 
or outer face of the pitch load fitting where damage or corrosion 
was detected, and make pad-up areas parallel, as applicable, in 
accordance with the service bulletin.
    (ii) Accomplish paragraph (d) of this AD.

    Note 3: 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.''

Option 2: High Frequency Eddy Current and Detailed Visual Inspections

    (c) Remove the upper link and accomplish the requirements of 
paragraphs (c)(1) and (c)(2) of this AD, in accordance with Boeing 
Service Bulletin 767-57-0053, Revision 2, dated September 23, 1999.
    (1) Perform a high frequency eddy current inspection to detect 
cracking of the pitch load fittings of the wing front spar.
    (2) Perform a detailed visual inspection of the inner and outer 
face pad-up areas of the pitch load fittings to detect damage or 
corrosion and to determine if the pad-up areas are parallel. Except 
as provided by paragraph (f) of this AD, if any damage, corrosion, 
or non-parallelism is detected, prior to further flight, rework the 
inner or outer face of the pitch load fitting where damage or 
corrosion was detected, and make pad-up areas parallel, as 
applicable, in accordance with the service bulletin.

Rework

    (d) For airplanes on which any cracking is detected during any 
inspection required by paragraph (b) of this AD, or on which the 
requirements of paragraph (c) of this AD have been accomplished: 
Prior to further flight, accomplish paragraph (d)(1) or (d)(2) of 
this AD, as applicable, in accordance with Boeing Service Bulletin 
767-57-0053, Revision 2, dated September 23, 1999; and accomplish 
paragraph (e) of this AD.
    (1) For airplanes inspected in accordance with paragraph (c) of 
this AD and on which no cracking was detected: Make an insurance cut 
of the pitch load fitting lug.
    (2) For airplanes on which any cracking was detected during any 
inspection required by paragraph (b) or (c) of this AD: Except as 
provided by paragraph (f) of this AD, rework the lugs of the pitch 
load fittings of the wing front spar.

Bushing Installation

    (e) For airplanes on which the requirements specified in 
paragraph (d) of this AD have been accomplished: Prior to further 
flight, install new bushings in the pitch load fittings of the wing 
front spar as

[[Page 68060]]

specified in paragraph (e)(1) or (e)(2) of this AD, in accordance 
with Boeing Service Bulletin 767-57-0053, Revision 2, dated 
September 23, 1999.
    (1) Option 1: Install new bushings using the high interference 
fit method, and repeat the inspections required by paragraph (b) or 
(c) of this AD at the intervals specified in Table 1.3 of Figure 1. 
of the service bulletin.
    (2) Option 2: Install new bushings using the FORCEMATE method, 
and repeat the inspections required by paragraph (b) or (c) of this 
AD at the interval specified in Table 1.4 of Figure 1. of the 
service bulletin.
    (f) If any damage is detected that is outside the limits 
specified in Boeing Service Bulletin 767-57-0053, Revision 2, dated 
September 23, 1999, and the service bulletin specifies to contact 
Boeing for appropriate action: 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 (DER) who has been authorized by the Manager, Seattle 
ACO, to make such findings. For a repair method to be approved, as 
required by this paragraph, the approval letter must specifically 
reference this AD.

Alternative Methods of Compliance

    (g) 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 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

    (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.

    Issued in Renton, Washington, on November 30, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-31476 Filed 12-3-99; 8:45 am]
BILLING CODE 4910-13-U