[Federal Register Volume 65, Number 132 (Monday, July 10, 2000)]
[Proposed Rules]
[Pages 42306-42309]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-17302]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-365-AD]
RIN 2120-AA64


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

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 powered by Pratt & Whitney engines. This proposal would 
require modification of the nacelle strut and wing structure. This 
action is necessary to prevent fatigue cracking in primary

[[Page 42307]]

strut structure and consequent reduced structural integrity of the 
strut. This action is intended to address the identified unsafe 
condition.

DATES: Comments must be received by August 24, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-365-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. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 99-NM-365-AD'' in the subject line and need not be 
submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    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 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.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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-365-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-365-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that the airplane 
manufacturer has accomplished a structural reassessment of the damage 
tolerance capabilities of the Boeing Model 767 series airplane powered 
by Pratt & Whitney engines. This reassessment indicates that the actual 
operational loads applied to the nacelle strut and wing structure are 
higher than the analytical loads that were used during the initial 
design. Subsequent analysis and service history, which includes 
numerous reports of fatigue cracking on certain strut and wing 
structure, indicate that fatigue cracking can occur on the primary 
strut structure before an airplane reaches its design service objective 
of 20 years or 50,000 flight cycles. Analysis also indicates that such 
cracking, if it were to occur, would grow at a much greater rate than 
originally expected. Fatigue cracking in primary strut structure would 
result in reduced structural integrity of the strut.

Other Relevant Rulemaking

    This proposed AD is related to AD 94-11-02, amendment 39-8918 (59 
FR 27229, May 26, 1994), which is applicable to all Boeing Model 767 
series airplanes, and requires repetitive detailed visual and eddy 
current inspections to detect cracks of certain midspar fuse pins, and 
replacement of any cracked midspar fuse pin with a new fuse pin.
    This proposed AD also is related to AD 99-07-06, amendment 39-11091 
(64 FR 14578, March 26, 1999), which is applicable to certain Boeing 
Model 767 series airplanes, and requires repetitive inspections to 
detect cracking or damage of the forward and aft lugs of the diagonal 
brace of the nacelle strut, and follow-on actions, if necessary.
    Accomplishment of the actions required by this AD would terminate 
the repetitive inspections required by AD 94-11-02 and AD 99-07-06.

Explanation of Relevant Service Information

    Boeing recently has developed a modification of the strut-to-wing 
attachment structure installed on Model 767 series airplanes powered by 
Pratt & Whitney engines. This modification significantly improves the 
load-carrying capability and durability of the strut-to-wing 
attachments. Such improvement also will substantially reduce the 
possibility of fatigue cracking and corrosion developing in the 
attachment assembly.
    The FAA has reviewed and approved Boeing Service Bulletin 767-54-
0080, dated October 7, 1999, which describes procedures for 
modification of the nacelle strut and wing structure. The modification 
consists of replacing many of the significant load-bearing components 
of the strut (e.g., the side link fittings assemblies, the midspar 
fittings, the side load fittings, certain fuse bolt assemblies, etc.) 
with improved components.
    The service bulletin contains a formula for calculating an optional 
compliance threshold for the specified modification. This formula is 
intended to be used as an alternative to the 20-year calendar threshold 
specified in the service bulletin.
    In addition, Table 2 of the service bulletin also identifies six 
related service bulletin modifications that must be accomplished before 
or at the same time as the modification specified in Boeing Service 
Bulletin 767-54-0080:
     Boeing Service Bulletin 767-53-0069: The FAA has reviewed 
and approved Boeing Service Bulletin 767-53-0069, Revision 1, dated 
January 29, 1998, which describes procedures for replacement of the 
existing midspar fuse pins with new higher-strength fuse pins; 
installation of new higher-strength tension bolts and radius fillers in 
the side load fittings and backup support structure; and replacement of 
the existing fasteners located in the front

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spar and rib number eight rib post with new higher-strength fasteners.
     Boeing Service Bulletin 767-54-0083: The FAA has reviewed 
and approved Boeing Service Bulletin 767-54-0083, dated September 17, 
1998, which describes procedures for replacement of the upper link with 
a new, improved part that will increase the strength and durability of 
the upper link installation. That service bulletin also describes 
procedures for modification of a wire support bracket attached to the 
upper link.
     Boeing Service Bulletin 767-54-0088: The FAA has reviewed 
and approved Boeing Service Bulletin 767-54-0088, Revision 1, dated 
July 29, 1999, which describes procedures for replacement of the upper 
link fuse pin and aft pin with new, improved pins that will increase 
the strength and durability of the upper link installation.
     Boeing Service Bulletin 767-54A0094: The FAA has reviewed 
and approved Boeing Service Bulletin 767-54A0094, Revision 1, dated 
September 16, 1999, which describes procedures for repetitive detailed 
visual inspections of the one-piece diagonal brace lugs to detect 
cracking, and installation of a new three-piece diagonal brace or 
rework of the existing brace. Installation of the new three-piece 
diagonal brace would constitute terminating action for the repetitive 
inspections described in this bulletin.
     Boeing Service Bulletin 767-57-0053: The FAA has reviewed 
and approved Boeing Service Bulletin 767-57-0053, Revision 2, dated 
September 23, 1999, which describes procedures for repetitive 
ultrasonic and eddy current inspections of the pitch load fitting lugs 
of the wing front spar for cracking, and rework of the fittings, if 
necessary.
     Boeing Service Bulletin 767-29-0057: The FAA has reviewed 
and approved Boeing Service Bulletin 767-29-0057, dated December 16, 
1993, including Notice of Status Change NSC 1, dated November 23, 1994, 
which describes procedures for modification of the electrical wiring 
located in the aft fairing area of the strut and installation of wire 
support brackets on the strut bulkhead.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition.

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 bulletins described previously, except as discussed below.

Difference Between Proposed Rule and Service Bulletin

    Operators should note that, although Boeing Service Bulletin 767-
54-0080 specifies that the manufacturer may be contacted for 
disposition of certain damage conditions that may be detected during 
accomplishment of the modification, this proposal would require the 
repair of those conditions to be accomplished in accordance with a 
method approved by the FAA.

Cost Impact

    There are approximately 233 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 76 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 708 work hours per airplane to 
accomplish the proposed modification of the nacelle strut and wing 
structure described in Boeing Service Bulletin 767-54-0080, at an 
average labor rate of $60 per work hour. Required parts would be 
provided at no cost by the airplane manufacturer. Based on these 
figures, the cost impact of the modification proposed by this AD on 
U.S. operators is estimated to be $3,228,480, or $42,480 per airplane.
    It would take approximately 106 work hours per airplane to 
accomplish the actions described in Boeing Service Bulletin 767-53-
0069, Revision 1, at an average labor rate of $60 per work hour. 
Required parts would be provided at no cost by the airplane 
manufacturer. Based on these figures, the cost impact of these proposed 
actions on U.S. operators is estimated to be $483,360, or $6,360 per 
airplane.
    It would take approximately 1 work hour per airplane to accomplish 
the actions described in Boeing Service Bulletin 767-54-0083, at an 
average labor rate of $60 per work hour. Required parts would be 
provided at no cost by the airplane manufacturer. Based on these 
figures, the cost impact of these proposed actions on U.S. operators is 
estimated to be $4,560, or $60 per airplane.
    It would take approximately 2 work hours per airplane to accomplish 
the actions described in Boeing Service Bulletin 767-54-0088, Revision 
1, at an average labor rate of $60 per work hour. Required parts would 
be provided at no cost by the airplane manufacturer. Based on these 
figures, the cost impact of these proposed actions on U.S. operators is 
estimated to be $9,120, or $120 per airplane.
    It would take approximately 20 work hours per airplane to 
accomplish the proposed actions described in Boeing Service Bulletin 
767-54A0094, Revision 1, at an average labor rate of $60 per work hour. 
Required parts would be provided at no cost by the airplane 
manufacturer. Based on these figures, the cost impact of these proposed 
actions on U.S. operators is estimated to be $91,200, or $1,200 per 
airplane.
    It would take approximately 5 work hours per airplane to accomplish 
the proposed actions described in Boeing Service Bulletin 767-57-0053, 
Revision 2, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of these proposed actions on U.S. 
operators is estimated to be $22,800, or $300 per airplane.
    It would take approximately 16 work hours per airplane to 
accomplish the proposed actions described in Boeing Service Bulletin 
767-29-0057, at an average labor rate of $60 per work hour. Required 
parts would be provided at no cost by the airplane manufacturer. Based 
on these figures, the cost impact of these proposed actions on U.S. 
operators is estimated to be $72,960, or $960 per airplane.
    The cost impact figures discussed above are 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 proposed 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 proposed herein would 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 proposal would not have federalism implications 
under Executive Order 13132.
    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

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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-365-AD.

    Applicability: Model 767 series airplanes powered by Pratt & 
Whitney engines, 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 
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 (d) 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 
consequent reduced structural integrity of the strut, accomplish the 
following:

Modifications

    (a) When the airplane has reached the flight cycle threshold as 
defined by the flight cycle threshold formula on page 67 of Boeing 
Service Bulletin 767-54-0080, dated October 7, 1999, or within 20 
years since the date of manufacture, whichever occurs first: Modify 
the nacelle strut and wing structure on both the left and right 
sides of the airplane, in accordance with the service bulletin. Use 
of the flight cycle threshold formula described on page 67 of the 
service bulletin is an acceptable alternative to the 20-year 
threshold, provided the conditions described in paragraphs 1 and 2 
of page 67 have been met.
    (b) Prior to or concurrently with the accomplishment of the 
modification of the nacelle strut and wing structure required by 
paragraph (a) of this AD; as specified in paragraph 1.D., Table 2, 
on page 8 of Boeing Service Bulletin 767-54-0080, dated October 7, 
1999; accomplish the actions specified in Boeing Service Bulletins 
767-53-0069, Revision 1, dated January 29, 1998; 767-54-0083, dated 
September 17, 1998; 767-54-0088, Revision 1, dated July 29, 1999; 
767-54A0094, Revision 1, dated September 16, 1999; 767-57-0053, 
Revision 2, dated September 23, 1999; and 767-29-0057, dated 
December 16, 1993, including Notice of Status Change NSC 1, dated 
November 23, 1994; as applicable; in accordance with those service 
bulletins. Accomplishment of this paragraph constitutes terminating 
action for the repetitive inspections required by AD 94-11-02, 
amendment 39-8918, and AD 99-07-06, amendment 39-11091.

    Note 2: Paragraph (b) of this AD specifies prior or concurrent 
accomplishment of Boeing Service Bulletin 767-57-0053, Revision 2, 
dated September 23, 1999; however, Table 2, on page 8 of Boeing 
Service Bulletin 767-54-0080, dated October 7, 1999, specifies prior 
or concurrent accomplishment of the original issue of the service 
bulletin. Therefore, accomplishment of the applicable actions 
specified in Boeing Service Bulletin 767-57-0053, dated June 27, 
1996, or Revision 1, dated October 31, 1996, prior to the effective 
date of this AD, is considered acceptable for compliance with the 
actions required by paragraph (b) of this AD.

Repair

    (c) If any damage to airplane structure is found during the 
accomplishment of the modification required by paragraph (a) of this 
AD; 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. 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.

Alternative Methods of Compliance

    (d) 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

    (e) 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 July 3, 2000.
Vi L. Lipski,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-17302 Filed 7-7-00; 8:45 am]
BILLING CODE 4910-13-U