Document ID: FAA-2007-0004-0054
Agency: faa
Document Type: Notice
Title: Airworthiness Directives; Boeing Model 737-100, -200, -200C, - 300, -400, and -500 Series Airplanes
Posted Date: 2007-08-16T04:00Z

[Federal Register: August 16, 2007 (Volume 72, Number 158)]
[Proposed Rules]               
[Page 45949-45952]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16au07-16]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28942; Directorate Identifier 2007-NM-093-AD]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (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 high-frequency eddy current inspections for cracking around the 
heads of the fasteners on the forward fastener row of certain areas of 
the station (STA) 259.5 circumferential butt splice, and repair if 
necessary. This proposed AD would also require a preventive 
modification, which would eliminate the need for the repetitive 
inspections. This proposed AD results from a report that an operator 
found multiple cracks in the fuselage skin of a Model 737-200 airplane, 
at the forward fastener row of the STA 259.5 circumferential butt 
splice between stringers 19 and 24. We are proposing this AD to prevent 
cracking of the STA 259.5 circumferential butt splice, which could 
result in loss of structural integrity of the fuselage skin and 
possible loss of cabin pressure.

DATES: We must receive comments on this proposed AD by October 1, 2007.

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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room W12-140 on the ground floor of the 
West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6447; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

[[Page 45950]]

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``Docket No. 
FAA-2007-28942; Directorate Identifier 2007-NM-093-AD'' at the 
beginning 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 received 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 post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, 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 may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov
, or in person at the Docket Operations office between 9 

a.m. and 5 p.m., Monday through Friday, except Federal holidays. The 
Docket Operations office (telephone (800) 647-5527) is located on the 
ground floor of the West Building at the DOT street address stated in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after the Docket Management System receives them.

Discussion

    We have received a report indicating that an operator found 
multiple cracks in the fuselage skin of a Model 737-200 airplane that 
had accumulated 69,350 total flight cycles. The cracking was found at 
the forward fastener row of the station (STA) 259.5 circumferential 
butt splice between stringers 19 and 24, and some cracks had joined 
into one large crack. This condition, if not corrected, could result in 
loss of structural integrity of the fuselage skin and possible loss of 
cabin pressure.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-53-
1267, dated November 28, 2006. The service bulletin describes 
procedures for doing repetitive detailed and high-frequency eddy 
current (HFEC) surface inspections for cracking around the heads of the 
fasteners on the forward fastener row of certain areas of the STA 259.5 
circumferential butt splice, and applicable repair if necessary. 
Certain areas of the circumferential butt splice are those described in 
the Accomplishment Instructions of Service Bulletin 737-53-1267 as 
areas that have not had a preventive modification installed in 
accordance with Boeing Service Bulletin 737-53-1076, or have not had a 
Boeing, FAA-approved repair accomplished.
    The service bulletin also describes procedures for doing a 
preventive modification of certain areas of the STA 259.5 
circumferential butt splice, including removing the existing fasteners, 
doing an HFEC rotary probe inspection of the fastener holes, and, if no 
crack is found, oversizing the holes and installing new protruding head 
fasteners. The preventive modification eliminates the need for the 
repetitive inspections.
    The service bulletin specifies compliance times that depend upon 
the number of total flight cycles accumulated by the airplane. 
Compliance times for doing the initial inspections begin at or before 
the accumulation of 50,000 total flight cycles, with grace periods 
ranging between 500 and 4,500 flight cycles after the release date of 
the service bulletin. The service bulletin specifies that repetitive 
inspections shall be done thereafter at intervals of 9,000 flight 
cycles, until the preventive modification is done. The service bulletin 
specifies that all repairs are to be done before further flight and 
that the preventive modification is to be done before the accumulation 
of 75,000 total flight cycles or within 6,000 flight cycles after the 
release date of the service bulletin, whichever comes later.
    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. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously.

Costs of Compliance

    There are about 2,150 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD, at an average labor 
rate of $80 per work hour. Required parts would be supplied by the 
operator.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                         Number of U.S.-
                Action                  Work       Cost per airplane       registered           Fleet cost
                                        hours                               airplanes
----------------------------------------------------------------------------------------------------------------
Inspection...........................       5  $400, per inspection                 654  $261,600, per
                                                cycle.                                    inspection cycle.
Preventive modification..............      24  $1,920..................             654  $1,255,680.
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on

[[Page 45951]]

products identified in this rulemaking action.

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 and placed it in the AD docket. 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.

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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-28942; Directorate Identifier 2007-NM-
093-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by October 
1, 2007.

Affected ADs

    (b) Accomplishing repairs and modifications described in 
paragraphs (f) and (g) of this AD is considered acceptable for 
compliance with repair requirements of paragraphs (f) and (g) of AD 
92-25-09, amendment 39-8424, for the areas of the station (STA) 
259.5 circumferential butt splice only.

Applicability

    (c) This AD applies to Boeing Model 737-100, -200, -200C, -300, 
-400, and -500 series airplanes, certificated in any category, as 
identified in Boeing Special Attention Service Bulletin 737-53-1267, 
dated November 28, 2006.

Unsafe Condition

    (d) This AD results from a report that an operator found 
multiple cracks in the fuselage skin of a Model 737-200 airplane, at 
the forward fastener row of the STA 259.5 circumferential butt 
splice between stringers 19 and 24. We are issuing this AD to 
prevent cracking of the STA 259.5 circumferential butt splice, which 
could result in loss of structural integrity of the fuselage skin 
and possible loss of cabin pressure.

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.

Inspections

    (f) At the applicable initial compliance time specified in 
paragraph 1.E. ``Compliance'' of Boeing Special Attention Service 
Bulletin 737-53-1267, dated November 28, 2006, except as provided by 
paragraph (j) of this AD: Do detailed and high-frequency eddy 
current inspections for cracking around the heads of the fasteners 
on the forward fastener row of certain areas of the station (STA) 
259.5 circumferential butt splice, by doing all of the actions 
specified in Part 1 of the Accomplishment Instructions of the 
service bulletin, except as provided by paragraph (i) of this AD. 
Repeat the inspections thereafter at the intervals specified in 
paragraph 1.E. of the service bulletin. Doing the preventive 
modification specified in paragraph (h) of this AD terminates the 
repetitive inspection requirements of this paragraph.

Repair

    (g) If any crack is found during any inspection required by this 
AD, before further flight, repair in accordance with Part 1 of the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-53-1267, dated November 28, 2006.

Preventive Modification

    (h) At the compliance time specified in paragraph 1.E. of Boeing 
Special Attention Service Bulletin 737-53-1267, dated November 28, 
2006, except as provided by paragraph (j) of this AD: Do the 
preventive modification in accordance with the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-53-
1267, dated November 28, 2006. Doing the preventive modification 
terminates the repetitive inspections required by paragraph (f) of 
this AD.

Modification or Repair Done in Accordance with AD 92-25-09

    (i) Inspections described by paragraph (f) of this AD are not 
required for areas of the STA 259.5 circumferential butt splice that 
have been modified in accordance with the service information 
specified in Table 1 of this AD. (Boeing Service Bulletin 737-53-
1076, Revision 4, dated September 26, 1991, is cited as an 
appropriate source of service information for doing certain 
requirements of AD 92-25-09.)

                                          Table 1.--Service Information
----------------------------------------------------------------------------------------------------------------
        Boeing Service Bulletin                    Revision level                            Date
----------------------------------------------------------------------------------------------------------------
737-53-1076...........................  4..................................  September 26, 1991.
737-53-1076...........................  3..................................  September 20, 1990.
737-53-1076...........................  2..................................  February 8, 1990.
737-53-1076...........................  1..................................  November 23, 1988.
737-53-1076...........................  Original Issue.....................  October 30, 1986.
----------------------------------------------------------------------------------------------------------------

Compliance Times

    (j) Where the service bulletin specifies compliance times 
relative to the release date of Boeing Special Attention Service 
Bulletin 737-53-1267, dated November 28, 2006, this AD requires 
compliance at compliance times relative to the effective date of 
this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing

[[Page 45952]]

Commercial Airplanes Delegation Option Authorization Organization 
who has been authorized by the Manager, Seattle ACO, to make those 
findings. For a repair method to be approved, the repair must meet 
the certification basis of the airplane, and the approval must 
specifically refer to this AD.

    Issued in Renton, Washington, on July 30, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-16104 Filed 8-15-07; 8:45 am]

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