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

[Federal Register Volume 65, Number 243 (Monday, December 18, 2000)]
[Rules and Regulations]
[Pages 78913-78915]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-31448]



[[Page 78913]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-365-AD; Amendment 39-12041; AD 2000-25-07]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 737-100, -200, and -200C series 
airplanes. This action requires repetitive inspections of the aft end 
of each inboard flap track of the wing outboard flap, and corrective 
actions, if necessary. This action is necessary to detect and correct 
damage of the aft end of each flap track, which could result in loss of 
the outboard trailing edge flap and consequent loss of controllability 
of the airplane.

DATES: Effective January 2, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 2, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before February 16, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-365-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-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 this AD 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; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

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: The FAA has received a report indicating 
that cracking of the aft end of an inboard flap track of the wing 
outboard flap was found on a Model 737-200 series airplane having 
improved flap tracks installed. The cracking was found during an 
inspection that was conducted to resolve problems with the trim that 
occurred during flight. The airplane had accumulated 38,484 flight 
cycles. The inner and outer webs of the track, as well as the upper and 
lower flanges, were severed. The only component holding the aft end of 
the flap track together was the fail-safe bar, which was bolted to the 
flap track. There was also a small section broken off the upper 
outboard chord. Further investigation revealed that the cracks were 
caused by corrosion at the fasteners that attach the fail-safe bar to 
the inner and outer webs. Such conditions, if not detected and 
corrected, could result in loss of the outboard trailing edge flap and 
consequent loss of controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing All Operator Message (AOM) 
M-7200-00-01854, dated July 27, 2000, which describes procedures for a 
close (detailed) visual inspection to detect damage (corrosion, 
cracking) of the aft end of the left- and right-hand inboard flap 
tracks of the wing outboard flap, and corrective actions. The 
corrective actions consist of, among other things, repair or rework of 
any damaged flap tracks.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to detect and correct damage of the aft end of each flap 
track at the wing buttock line of the inboard flap track of the wing 
outboard flap, which could result in loss of the outboard trailing edge 
flap and consequent loss of controllability of the airplane. This AD 
requires accomplishment of the inspection and corrective actions 
specified in the service information described previously, except as 
discussed below.

Differences Between All Operators Message and This AD

    Operators should note that the effectivity listing of the AOM 
specifies all Boeing Model 737-100 and -200 series airplanes. However, 
this AD is applicable to certain Boeing Model 737-100, -200, and -200C 
series airplanes on which the flap tracks have certain Boeing part 
numbers. The subject flap tracks may have been removed from an airplane 
and re-installed, without being inspected, on another airplane. 
Therefore, the FAA finds it necessary to revise the applicability of 
this AD by limiting the repetitive inspections to only certain Boeing 
Model 737-100, -200, and -200C series airplanes on which certain flap 
tracks have been installed.
    The AOM specifies a one-time close visual inspection of the aft end 
of the left- and right-hand inboard flap tracks of the wing outboard 
flap. This AD requires the applicable inspection to be repeated at 
intervals not to exceed 1,200 flight cycles, regardless of detection of 
cracking. The FAA has determined that, because of the safety 
implications and consequences associated with fracture of the aft end 
of each inboard flap track of the wing outboard flap, repetitive 
inspections are necessary.
    The AOM references only one flap track part number (P/N) 65-46428-
25. The FAA has determined that there are other flap tracks with 
similar configurations at the aft end that have different P/N's, and 
those flap tracks would be subject to the same unsafe condition.
    Additionally, the AOM specifies that the manufacturer may be 
contacted for disposition of certain repair conditions, however, this 
AD requires the repair of those conditions to be accomplished per a 
method approved by the FAA, or per data meeting the type certification 
basis of the airplane approved by a Boeing Company Designated 
Engineering Representative who has been authorized by the FAA to make 
such findings.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and

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opportunity for prior public comment hereon are impracticable, and that 
good cause exists for making this amendment effective in less than 30 
days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Submit comments using the following format:
    <bullet> 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.
    <bullet> For each issue, state what specific change to the AD is 
being requested.
    <bullet> 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 rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-365-AD.'' The postcard will be date stamped 
and returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

2000-25-07  Boeing: Amendment 39-12041. Docket 2000-NM-365-AD.

    Applicability: Model 737-100, -200, and -200C series airplanes; 
on which the left- or right-hand inboard flap tracks of the wing 
outboard flap have a part number (P/N) listed in Table 1 (below) of 
this AD; certificated in any category.

             Table 1.--Boeing Flap Tracks Subject to This AD
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                          Name                              Part Number
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Boeing..................................................     65-46428-9
                                                             65-46428-15
                                                             65-46428-17
                                                             65-46428-19
                                                             65-46428-21
                                                             65-46428-23
                                                             65-46428-25
                                                             65-46428-27
                                                             65-46428-33
                                                             65-46428-35
------------------------------------------------------------------------


    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 per 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 detect and correct damage of the aft end of each inboard flap 
track of the wing outboard flap, which could result in loss of the 
outboard trailing edge flap and consequent loss of controllability 
of the airplane, accomplish the following:

Repetitive Inspections

    (a) Do a detailed visual inspection to detect damage (corrosion, 
cracking) of the aft end of the left- and right-hand inboard flap 
tracks of the wing outboard flap, per Boeing All Operator Message 
(AOM) M-7200-00-01854, dated July 27, 2000; at the latest of the 
times specified in paragraphs (a)(1), (a)(2), and (a)(3) of this AD. 
Repeat the inspection thereafter at intervals not to exceed 1,200 
flight cycles.

    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) Within 30 days after the effective date of this AD.
    (2) Within 1,200 flight cycles after the last documented 
inspection or overhaul of the aft end of each flap track.
    (3) Before the accumulation of 15,000 total flight cycles.

Corrective Actions

    (b) If any damage (corrosion, cracking) is detected, before 
further flight, repair or rework the flap track per the ``Repair and 
Rework Instructions'' specified in Boeing AOM M-7200-00-01854, dated 
July 27, 2000. Where the AOM specifies that the manufacturer may be 
contacted for

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disposition of certain corrective actions (i.e., repair and/or 
rework of the flaps), this AD requires such repair and/or rework to 
be done per a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA; or per 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 by the Manager, Seattle ACO, as required by 
this paragraph, the Manager's approval letter must specifically 
reference this AD.

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 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

    (d) Special flight permits may be issued per 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.

Incorporation by Reference

    (e) Except as provided by paragraph (b) of this AD, the actions 
shall be done per Boeing All Operator Message M-7200-00-01854, dated 
July 27, 2000. This incorporation by reference was approved by the 
Director of the Federal Register per 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

    (f) This amendment becomes effective on January 2, 2001.

    Issued in Renton, Washington, on December 5, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-31448 Filed 12-15-00; 8:45 am]
BILLING CODE 4910-13-U

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