[Federal Register Volume 67, Number 1 (Wednesday, January 2, 2002)]
[Proposed Rules]
[Pages 35-38]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-32195]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-209-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 an inspection of the tripod 
strut assembly of the inboard support of the leading edge slat of the 
wing for a preload condition, and follow-on actions. For certain 
airplanes, this proposal also would require inspection and replacement 
of the existing tripod struts with new, adjustable struts, if 
necessary. This action is necessary to prevent damage to the tripod 
strut assembly due to a preload condition, which could result in loss 
of control of the inboard leading edge slat or separation of the slat 
from the airplane, and consequent reduced controllability of the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Comments must be received by February 19, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-209-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. 2001-NM-209-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: 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:

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 action 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.

[[Page 36]]

     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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-209-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. 2001-NM-209-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The airplane manufacturer has informed the FAA that damaged 
bushings were found in the tripod strut assembly of the inboard support 
of the leading edge slat of the wings of a Model 767 series airplane in 
production. The damage was due to preload in the tripod assembly during 
installation. The tripod assembly is used to support the inboard 
leading edge slat and is the primary inboard-outboard load path of the 
slat. Loss of primary inboard-outboard load path for the slat can 
result in an unstable slat-to-wing connection, and separation of the 
slat from the airplane. Such conditions, if not corrected, could result 
in reduced controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 767-
57A0058, Revision 1, dated May 27, 1999, which describes procedures for 
a check (inspection) of the tripod strut assembly of the inboard 
support of the leading edge slat of the wing for a preload condition, 
and follow-on actions. The follow-on actions include:
     If no preload condition is found, a visual inspection of 
the components in the fitting assembly to determine if bushing holes 
are round.
     Replacement of the fitting assembly if the bushing holes 
are not round.
     If a preload condition is found, a high frequency eddy 
current inspection of the lug bore and base of the fitting assembly for 
cracking.
     Rework of the fitting assembly if no cracking is found, or 
if cracking is found in the lug bore only.
     Replacement of the fitting assembly if cracking is found 
in the lug base or the lug bore and base.
     Adjustment of the tripod struts, if necessary, to 
eliminate preload condition, and a check of the rigging of the inboard 
leading edge slat, and re-rigging if necessary.
     For certain airplanes, inspection for improperly cut and 
spliced struts, and strut replacement, if necessary.
    The FAA also has reviewed and approved Boeing Service Bulletin 767-
57-0037, dated January 14, 1993. For Group 2 airplanes (as defined in 
the service bulletin) the service bulletin describes procedures for 
doing a visual inspection of the tripod struts of the inboard leading 
edge of the wings to determine if they have been cut and spliced, and 
replacement with new, adjustable struts if the existing struts are cut 
and spliced with fewer than six hi-loks.
    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 certain actions specified 
in the service bulletins described previously, except as discussed 
below.

Differences Between This Proposed AD and the Service Bulletins

    The service bulletins do not specify what type of visual inspection 
of the tripod assembly and tripod struts should be used. The FAA has 
determined that the procedures in the service bulletins describe a 
general visual inspection. Note 2 of this proposed AD defines that type 
of inspection.
    Other differences include the following:
     Boeing Service Bulletin 767-57A0058, Revision 1, specifies 
doing a ``check'' for preload, however, this proposed AD uses the term 
``general visual inspection.''
     The compliance time for doing the actions specified in the 
Boeing Service Bulletin 767-57A0058, Revision 1, is within 5,000 flight 
cycles or 24 months after the receipt of the service bulletin, 
whichever comes first. The airplane manufacturer has informed us that 
``whichever comes first'' is an error in the compliance time and would 
put certain airplanes immediately out of compliance. The correct 
compliance time is ``whichever comes later,'' and this proposed AD 
requires that compliance time.
     The effectivity in Boeing Service Bulletin 767-57-0037 
specifies line numbers 1 through 469 inclusive. The airplane 
manufacturer has informed us that line numbers 1 through 159 inclusive 
had a fixed strut which was not cut and spliced or preloaded. Line 
numbers 160 through 469 inclusive may have had a fixed strut which was 
cut and spliced, and if it was not cut and spliced it was still subject 
to being preloaded. Therefore, the affected line numbers are 160 
through 469 inclusive, and those line numbers are included in this 
proposed AD.

Cost Impact

    There are approximately 379 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 136 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed inspections of the tripod strut assembly and bushing 
holes, at an average labor rate of $60 per work hour. Based on these 
figures, the cost impact of the inspections proposed by this AD on U.S. 
operators is estimated to be $8,160, or $60 per airplane.
    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 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.
    Should an operator be required to accomplish the rework of the 
fitting assembly, it would take approximately 4 work hours per airplane 
to accomplish the proposed rework, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the proposed 
rework would be $240 per airplane.
    Should an operator be required to accomplish the high frequency 
eddy current inspection, it would take

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approximately 5 work hours per airplane to accomplish the proposed 
inspection, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the proposed inspection would be $300 
per airplane.
    Should an operator be required to accomplish the replacement of the 
main strut support fitting, it would take approximately 14 work hours 
per airplane to accomplish the proposed replacement (on both the left 
and right wings of the airplane, excluding the time for gaining access 
and closing up), at an average labor rate of $60 per work hour.
    Required parts would cost approximately $12,380 per airplane. Based 
on these figures, the cost impact of the proposed replacement would be 
$13,220 per airplane.
    Should an operator be required to accomplish the inspection for 
improperly cut and spliced struts, it would take approximately 1 work 
hour per airplane to accomplish the proposed inspection, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the inspection of the struts proposed by this AD would be $60 
per airplane.
    Should an operator be required to accomplish the replacement of a 
cut and spliced strut with a new, adjustable tripod strut, it would 
take approximately 4 work hours per airplane to accomplish the proposed 
replacement, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the replacement proposed by this AD 
would be $240 per airplane.

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 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 2001-NM-209-AD.

    Applicability: Model 767 series airplanes, line numbers 160 
through 541 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 (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 damage to the tripod strut assembly due to a preload 
condition, which could result in loss of control of the inboard 
leading edge slat or separation of the slat from the airplane, and 
consequent reduced controllability of the airplane, accomplish the 
following:

Inspections

    (a) For all airplanes: Before the accumulation of 5,000 total 
flight cycles or within 24 months after the effective date of this 
AD, whichever is later: Do a general visual inspection (check) of 
the tripod strut assembly of the inboard leading edge slat of each 
wing for a preload condition, per Figure 2 of Boeing Service 
Bulletin 767-57A0058, Revision 1, dated May 27, 1999.


    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.''

    (1) If no preload condition is found, before further flight, 
inspect the fitting assembly bushing holes for roundness, per Figure 
5 of the Accomplishment Instructions of the service bulletin.
    (i) If all the bushing holes are round, before further flight, 
do the inspection required by paragraph (c) of this AD.
    (ii) If any bushing hole is not round, before further flight, do 
the inspections required by paragraphs (b) and (c) of this AD.
    (2) If a preload condition is found, before further flight, do 
the inspections required by paragraphs (b) and (c) of this AD.

Follow-on Actions

    (b) For airplanes subject to paragraph (a)(1)(ii) or (a)(2) of 
this AD: Do a high frequency eddy current inspection of the fitting 
assembly lug for cracking, per Figure 6 of the Accomplishment 
Instructions of Boeing Service Bulletin 767-57A0058, Revision 1, 
dated May 27, 1999.
    (1) If no cracking is found, or if cracking is found in the lug 
bore only, before further flight, rework the fitting assembly lug 
per Figure 7 of the Accomplishment Instructions of the service 
bulletin.
    (2) If cracking is found in the fitting lug base or the lug bore 
and base, before further flight, purge the auxiliary fuel tank and 
replace the fitting assembly lug per Figure 8 of the Accomplishment 
Instructions of the service bulletin.
    (c) For airplanes subject to paragraph (a)(1)(i), (a)(1)(ii), or 
(a)(2) of this AD: Do a general visual inspection of the bushing 
holes of the main strut assembly to determine if the bushing holes 
are round, per Figure 9 of the Accomplishment Instructions of Boeing 
Service Bulletin 767-57A0058, Revision 1, dated May 27, 1999.
    (1) If the bushing holes are round, before further flight, 
assemble the tripod assembly per Figure 11 or Figure 12, as 
applicable, of the Accomplishment Instructions of the service 
bulletin.
    (2) If the bushing holes are not round, before further flight, 
replace the main strut fitting assembly per Figure 10 of the 
Accomplishment Instructions of the service bulletin, then assemble 
the tripod assembly per Figure 11 or Figure 12, as applicable, of 
the Accomplishment Instructions of the service bulletin.


    Note 3: Inspections and follow-on actions done before the 
effective date of this AD per Boeing Alert Service Bulletin 767-
57A0058, dated June 11, 1998, are considered acceptable for 
compliance with the applicable actions specified in this AD.

Inspection/Replacement of Tripod Struts

    (d) For Group 2 airplanes that have not accomplished Boeing 
Service Bulletin 767-57-0037, dated January 14, 1993: Before further 
flight after doing the inspections and follow-on actions required by 
paragraphs (a),

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(b), and (c) of this AD, do a general visual inspection of the 
tripod struts to determine if they have been cut and spliced, per 
the Accomplishment Instructions of the service bulletin.
    (1) If the tripod struts have been cut and spliced with fewer 
than six hi-loks, before further flight, replace with new, 
adjustable struts, per Figure 1 of the Accomplishment Instructions 
of the service bulletin.
    (2) If the tripod struts have not been cut and spliced, or they 
have been cut and spliced with six hi-loks, no further action is 
required by this paragraph.

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 Aircraft Certification 
Office (ACO), FAA. 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 Permit

    (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.

    Issued in Renton, Washington, on December 26, 2001.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-32195 Filed 12-31-01; 8:45 am]
BILLING CODE 4910-39-U