[Federal Register Volume 66, Number 143 (Wednesday, July 25, 2001)]
[Proposed Rules]
[Pages 38583-38585]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-18437]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-381-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 707 and 720 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 707 and 720 
series airplanes. This proposal would require installation of a new 
support structure for the trailing edge beam and main landing gear 
uplock mechanism. This action is necessary to prevent cracking in the 
frame and adjacent structure near the attach bolt of the main landing 
gear uplock mechanism, which could lead to compromised structural 
integrity. This action is intended to address the identified unsafe 
condition.

DATES: Comments must be received by September 10, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-381-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 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. 2000-NM-381-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: Duong Tran, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2773; 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.
     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 2000-NM-381-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. 2000-NM-381-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that cracks have been 
discovered in station 900 frame and its adjacent structure, near the 
attach bolt of the main landing gear (MLG) uplock mechanism. These 
cracks were caused by flexure of the wing, imposing

[[Page 38584]]

bending loads on the frame, in addition to the normal tension loads. 
This cracking condition, if not corrected, could result in compromised 
structural integrity of the MLG.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 2411, 
Revision 2, dated April 29, 1968, which describes procedures for, among 
other things, the installation of a new support structure for the 
trailing edge beam and main landing gear uplock mechanism. 
Accomplishment of the actions specified in the service bulletin 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 bulletin described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that this proposed AD would mandate the 
preventative modification described in Part III--Modification Data of 
the Accomplishment Instructions of Boeing Service Bulletin 2411, 
Revision 2, dated April 29, 1968, prior to the accumulation of 20,000 
total flight cycles, or within 24 months from the effective date of the 
AD, whichever occurs later. (Incorporation of the specified 
preventative modification is recommended in the service bulletin ``at 
the next major overhaul,'' except for repair.)
    The proposed AD also differs from the service bulletin in that it 
would not require the repetitive inspections to detect cracks in the 
support structure for the trailing edge beam and main landing gear 
uplock. The decision to mandate the preventative modification of the 
main landing gear uplock mechanism is based on the FAA's determination 
that long-term continued operational safety will be better assured by 
design changes to remove the source of the problem, rather than by 
repetitive inspections. Long-term inspections may not provide the 
degree of safety assurance necessary for the transport airplane fleet. 
This, coupled with a better understanding of the human factors 
associated with numerous continual inspections, has led the FAA to 
consider placing less emphasis on inspections and more emphasis on 
design improvements. The proposed preventative modification requirement 
is consistent with these findings.

Cost Impact

    There are approximately 84 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 10 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
80 work hours per airplane to accomplish the proposed modification, and 
that the average labor rate is $60 per work hour. Required parts would 
cost approximately $15,000 per airplane. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$198,000, or $19,800 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.

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 2000-NM-381-AD.

    Applicability: Model 707 and 720 series airplanes, certificated 
in any category, as listed in Boeing Service Bulletin 2411, Revision 
2, dated April 29, 1968.

    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 (b) 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 cracking in the frame and adjacent structure near the 
attach bolt of the main landing gear (MLG) uplock mechanism, which 
could lead to compromised structural integrity of the MLG, 
accomplish the following:

Modification

    (a) Prior to the accumulation of 20,000 flight cycles, or within 
24 months from the effective date of this AD, whichever occurs 
later, install a new support structure for the MLG uplock mechanism 
in accordance with Part III--Modification Data of the Accomplishment 
Instructions of Boeing Service Bulletin 2411, Revision 2, dated 
April 29, 1968.

Alternative Methods of Compliance

    (b) 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

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Inspector, who may add comments and then send it to the Manager, 
Seattle ACO.

    Note 2: 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

    (c) Special flight permits may be issued in accordance with 
Secs. 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 18, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-18437 Filed 7-24-01; 8:45 am]
BILLING CODE 4910-13-P