[Federal Register Volume 66, Number 71 (Thursday, April 12, 2001)]
[Proposed Rules]
[Pages 18878-18880]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-9021]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-401-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, and -200C 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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[[Page 18879]]

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 737-100, -
200, and -200C series airplanes. This proposal would require a one-time 
detailed visual inspection of the carriage spindles on the outboard 
midflap for circumferential score marks; and rework of the carriage 
spindles or replacement with new or serviceable spindles, if necessary. 
This action is necessary to prevent severe flap asymmetry due to 
fractures of both carriage spindles at an outboard midflap, which could 
result in loss of controllability of the airplane. This action is 
intended to address the identified unsafe condition.

DATES: Comments must be received by May 29, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-401-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-401-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: Nenita Odesa, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2557; 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-401-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-401-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The manufacturer has informed the FAA of four reports of carriage 
spindle fractures at the outboard midflap. These fractures were found 
in an area forward of the spherical bearing. The cause of such 
fractures was attributed to improper overhaul of spindle surfaces. 
Findings indicated circumferential scores on the forward end of the 
spindle. The manufacturer reports that one fracture on the carriage 
spindle for each flap will not affect safety of flight, and that such a 
condition could be detected and corrected with control input by the 
pilot. However, two fractured carriage spindles in an outboard flap 
will affect safety of flight, and this condition can be difficult to 
correct with control input by the pilot. Such a condition, if not 
corrected, could result in severe flap asymmetry due to fractures of 
both spindles at an outboard midflap, which could result in loss of 
controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-57A1256, dated September 30, 1999, which describes procedures for a 
one-time inspection of the forward end of the carriage spindles on the 
outboard midflap for circumferential scores; and rework of the carriage 
spindle or replacement with a new or serviceable spindle, if necessary. 
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.

Cost Impact

    There are approximately 870 Model 737-100, -200, and ``200C series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 320 airplanes of U.S. registry would be affected by this 
proposed AD, that it would take approximately 12 work hours per 
airplane to accomplish the proposed actions, 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 $230,400, or $720 
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

[[Page 18880]]

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-401-AD.

    Applicability: Model 737-100, -200, and -200C airplanes, not 
having high gross weight flaps installed; 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 (c) 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 severe flap asymmetry due to fractures of both 
carriage spindles at an outboard midflap, which could result in loss 
of controllability of the airplane, accomplish the following:

One-Time Detailed Visual Inspection

    (a) Within 18 months after the effective date of this AD, do a 
one-time detailed visual inspection of the outboard midflap carriage 
spindles for circumferential score marks per Boeing Alert Service 
Bulletin 737-57A1256, dated September 30, 1999.

    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.''

    (1) If no scoring is found on any carriage spindle, no further 
action is required by this paragraph.
    (2) If any scoring is found on any carriage spindle, before 
further flight, rework the carriage spindle, or replace it with a 
new or serviceable spindle per the service bulletin.

Spares

    (b) As of the effective date of this AD, no person shall install 
any outboard midflap carriage spindle having a part number 
identified in paragraph 2.E. of Boeing Alert Service Bulletin 737-
57A1256, dated September 30, 1999, on any airplane, unless the 
spindle has been inspected for score marks and reworked, as 
necessary, per the service bulletin.

Alternative Methods of Compliance

    (c) 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 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 Permit

    (d) 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 April 5, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-9021 Filed 4-11-01; 8:45 am]
BILLING CODE 4910-13-U