[Federal Register Volume 69, Number 171 (Friday, September 3, 2004)]
[Proposed Rules]
[Pages 53858-53860]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-20125]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18997; Directorate Identifier 2004-NM-19-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes. This proposed AD would require repetitive detailed 
and eddy current inspections to detect cracking of the frame web around 
the cutout for the doorstop intercostal strap at the aft side of the 
Body station 291.5 frame at stringer 16R, and corrective actions if 
necessary. This proposed AD is prompted by reports of fatigue cracks in 
the web of the Body station 291.5 frame near the forward galley door. 
We are proposing this AD to detect and correct fatigue cracking of the 
aft frame and frame support structure of the forward galley door, which 
could result in a severed fuselage frame web, rapid decompression of 
the airplane, and possible loss of the forward galley door.

DATES: We must receive comments on this proposed AD by October 18, 
2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     By fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., room PL-401, on 
the plaza level of the Nassif Building, Washington, DC.

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:

Docket Management System (DMS)

    The FAA has implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, new AD actions are posted on DMS 
and assigned a docket number. We track each action and assign a 
corresponding directorate identifier. The DMS AD docket number is in 
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane 
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier 
(``Old Docket Number'') as a cross-reference for searching purposes.

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES1. Include ``Docket No. FAA-2004-18997; 
Directorate Identifier 2004-NM-19-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments submitted by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also

[[Page 53859]]

post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that website, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You can review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
can visit http://dms.dot.gov.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

    You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the DMS receives them.

Discussion

    We have received reports of fatigue cracks in the web of the Body 
station 291.5 frame near the forward galley door of a Model 737-200 
series airplane. The cracks initiate at the frame web cutout for the 
stringer 16R doorstop intercostal strap. Fatigue cracking of the aft 
frame and frame support structure of the forward galley door, if not 
detected and corrected, could result in a severed fuselage frame web, 
rapid decompression of the airplane, and possible loss of the forward 
galley door.
    The subject area on certain Boeing Model 737-100, -200C, -300, -
400, and -500 series airplanes is similar to that on the affected Model 
737-200 series airplanes. Therefore, those airplanes may be subject to 
the unsafe condition revealed on the Model 737-200 series airplanes.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-53A1241, dated 
June 13, 2002. The alert service bulletin describes procedures for 
performing repetitive detailed and eddy current inspections to detect 
cracking of the frame web around the cutout for the doorstop 
intercostal strap at the aft side of the Body station 291.5 frame at 
stringer 16R, and corrective action if necessary. The alert service 
bulletin also specifies to contact Boeing for repair instructions if 
any crack is found. Accomplishing the actions specified in the service 
information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. Therefore, we are proposing this AD, which 
would require repetitive detailed and eddy current inspections to 
detect cracking of the frame web around the cutout for the doorstop 
intercostal strap at the aft side of the Body station 291.5 frame at 
stringer 16R, and corrective action if necessary. The proposed AD would 
require you to use the service information described previously to 
perform these actions, except as discussed under ``Differences Between 
the Proposed AD and Service Bulletin.''

Differences Between the Proposed AD and Service Bulletin

    The alert service bulletin states that the threshold for the 
inspections is 50,000 total flight cycles or 2,250 flight cycles after 
the release date of the service bulletin, whichever is later. This 
proposed AD would require a threshold of 40,000 total flight cycles or 
2,250 flight cycles after the effective date of the AD, whichever is 
later. The threshold for the proposed AD is based upon service history 
reported after the release of the service bulletin. The manufacturer 
intends to issue a revised service bulletin that includes a threshold 
of 40,000 total flight cycles.
    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.

Costs of Compliance

    This proposed AD would affect about 3,113 airplanes worldwide. The 
following table provides the estimated costs for U.S. operators to 
comply with this proposed AD.

                                                                     Estimated Costs
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                                                                                                                  Number of U.S.-
            Action                Work hours       Average labor           Parts            Cost per airplane       registered           Fleet cost
                                                   rate per hour                                                     airplanes
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Inspection, per inspection                   2               $65   None.................  $130, per inspection               876   $113,880, per
 cycle.                                                                                    cycle.                                   inspection cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

[[Page 53860]]

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2004-18997; Directorate Identifier 2004-NM-
19-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by October 18, 2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-100, -200, -200C, -300, 
-400, and -500 series airplanes, as listed in Boeing Alert Service 
Bulletin 737-53A1241, dated June 13, 2002; certificated in any 
category.

Unsafe Condition

    (d) This AD was prompted by reports of fatigue cracks in the web 
of the Body station 291.5 frame near the forward galley door. We are 
issuing this AD to detect and correct fatigue cracking of the aft 
frame and frame support structure of the forward galley door, which 
could result in a severed fuselage frame web, rapid decompression of 
the airplane, and possible loss of the forward galley door.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Initial and Repetitive Inspections

    (f) Prior to the accumulation of 40,000 total flight cycles, or 
within 2,250 flight cycles after the effective date of this AD, 
whichever occurs later: Do a detailed inspection and an eddy current 
inspection to detect cracking of the frame web around the cutout for 
the doorstop intercostal strap at the aft side of the Body station 
291.5 frame at stringer 16R, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1241, dated 
June 13, 2002. If no cracking is found, 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: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

Corrective Action

    (g) If any crack is found during any inspection required by this 
AD: 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 (AMOCs)

    (h) The Manager, Seattle ACO, has the authority to approve AMOCs 
for this AD, if requested in accordance with the procedures found in 
14 CFR 39.19.

    Issued in Renton, Washington, on August 20, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-20125 Filed 9-2-04; 8:45 am]
BILLING CODE 4910-13-P