[Federal Register Volume 69, Number 33 (Thursday, February 19, 2004)]
[Proposed Rules]
[Pages 7706-7707]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-3493]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 69, No. 33 / Thursday, February 19, 2004 / 
Proposed Rules  

[[Page 7706]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-208-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-200C 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 all Boeing Model 737-200C series 
airplanes. This proposal would require repetitive inspections of the 
Station 348.2 frame to detect cracking under the stop fittings and 
intercostal flanges at Stringers 14L, 15L, and 16L; and corrective 
action if necessary. This action is necessary to prevent rapid 
decompression of the airplane, and possible separation of the forward 
entry door from the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by April 5, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2003-NM-208-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. 2003-NM-208-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 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplanes, 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: Howard Hall, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6430; fax (425) 917-6590.

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:
    [sbull] 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.
    [sbull] For each issue, state what specific change to the proposed 
AD is being requested.
    [sbull] 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 2003-NM-208-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. 2003-NM-208-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report of cracks in the Station 348.2 frame 
on a Boeing Model 737-200C series airplane. The Station 348.2 frame is 
located immediately aft of the forward entry door cutout. The cracks 
were located under the door stop fittings at Stringers 15L and 16L. 
Undetected fatigue cracks in the frame could propagate due to normal 
cyclic cabin pressure loading. If these fatigue cracks continue to 
propagate, the stop fittings can become ineffective. This condition, if 
not corrected, could result in a rapid decompression of the airplane, 
and possible separation of the forward entry door from the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-53A1240, dated April 10, 2003, which describes procedures for 
performing repetitive detailed and eddy current inspections of the 
Station 348.2 frame for cracks under the stop fittings and intercostal 
flanges at Stringers 14L, 15L, and 16L. (Stringer 14L is similar to 
Stringers 15L and 16L.) The inspection procedures at these locations 
consist of: A detailed inspection of the entire area; an eddy current 
inspection of the forward surface of the Station 348.2 frame inner 
chord over a 4.0-inch length centered on the removed stop fittings at 
Stringers 15L and 16L; an eddy current rotary probe inspection of the 
frame at the fastener holes for the removed stop fittings at Stringers 
14L, 15L, and 16L; an eddy current inspection of the intercostal 
forward flanges common to the aft side of the Station 348.2 frame at 
Stringers 14L, 15L, and 16L; and an eddy current inspection of the 
intercostal aft flange common to the forward side of the Station 360 
frame at Stringer 15L. The alert service bulletin

[[Page 7707]]

also specifies contacting Boeing for repair instructions if cracks are 
found.

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 alert service bulletin described previously, except as discussed 
below.

Differences Between Proposed Rule and Alert Service Bulletin

    Although the alert service bulletin specifies that operators may 
contact the manufacturer for disposition of certain cracking 
conditions, this proposed AD would require operators to repair those 
conditions 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.

Cost Impact

    There are approximately 78 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 15 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
18 work hours per airplane to accomplish the proposed inspections, and 
that the average labor rate is $65 per work hour. Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $17,550, or $1,170 per airplane, per inspection cycle.
    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 2003-NM-208-AD.

    Applicability: All Model 737-200C series airplanes; certificated 
in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent rapid decompression of the airplane, and possible 
separation of the forward entry door from the airplane, accomplish 
the following:

Initial and Repetitive Inspections

    (a) Except as provided by paragraph (b) of this AD: Prior to the 
accumulation 46,000 total flight cycles, or within 2,250 flight 
cycles after the effective date of this AD, whichever occurs later, 
do detailed and eddy current inspections of the Station 348.2 frame 
for cracking under the stop fittings and intercostal flanges at 
Stringers 14L, 15L, and 16L by accomplishing paragraphs 3.A. and 
3.B.1. through 3.B.7. of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1240, dated April 10, 2003. Do the 
actions per the service bulletin. Any applicable repair must be 
accomplished prior to further flight. Repeat the inspections 
thereafter at intervals not to exceed 4,500 flight cycles.

    Note 1: For the purposes of this AD, a detailed 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.''

Corrective Action

    (b) If any crack is found during any inspection required by this 
AD, and the bulletin specifies to contact Boeing for appropriate 
action: Before further flight, repair 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 who has 
been authorized by the Manager, Seattle ACO, to make such findings. 
For a repair method to be approved, the approval must specifically 
reference this AD.

Alternative Methods of Compliance

    (c) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, 
FAA, is authorized to approve alternative methods of compliance 
(AMOCs) for this AD.


    Issued in Renton, Washington, on February 9, 2004.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-3493 Filed 2-18-04; 8:45 am]
BILLING CODE 4910-13-P