[Federal Register Volume 70, Number 82 (Friday, April 29, 2005)]
[Proposed Rules]
[Pages 22272-22274]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-8578]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 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.
 
 ========================================================================
 

  Federal Register / Vol. 70, No. 82 / Friday, April 29, 2005 / 
Proposed Rules  

[[Page 22272]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20918; Directorate Identifier 2004-NM-269-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. This proposed AD would require a one-time inspection for 
scribe lines and cracks in the fuselage skin at certain lap joints, 
butt joints, external repair doublers, and other areas; and related 
investigative/corrective actions if necessary. This proposed AD is 
prompted by reports of fuselage skin cracks adjacent to the skin lap 
joints on airplanes that had scribe lines. Scribe line damage can also 
occur at many other locations, including butt joints, external 
doublers, door scuff plates, the wing-to-body fairing, and areas of the 
fuselage where decals have been applied or removed. We are proposing 
this AD to prevent rapid decompression of the airplane due to fatigue 
cracks resulting from scribe lines on pressurized fuselage structure.

DATES: We must receive comments on this proposed AD by June 13, 2005.

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 Airplanes, 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 in person 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. This 
docket number is FAA-2005-20918; the directorate identifier for this 
docket is 2004-NM-269-AD.

FOR FURTHER INFORMATION CONTACT: Sue Lucier, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6438; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

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 under ADDRESSES. Include ``Docket No. FAA-2005-20918; 
Directorate Identifier 2004-NM-269-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 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 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.

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 a report of scribe lines and fuselage skin cracks 
adjacent to the skin lap joints on two Boeing Model 737-200 series 
airplanes. Scribe lines are narrow, shallow, distinct lines of damage, 
usually associated with the removal of a fillet seal (from a lap joint) 
or gap seal (from a butt splice). Scribe lines have typically occurred 
during maintenance, including, for example, applying and removing 
graphic decals and stripping paint sealant from the lap joints, butt 
joints, certain external doublers, door scuff plates, and the wing-to-
body fairing.
    On one of the subject airplanes, a 5-inch crack was found at (body) 
station (STA) 827, just below the lap joint at stringer (S) S-4R. The 
airplane had accumulated 52,226 total flight cycles. On the second 
airplane, two cracks were found below the S-10R lap joint: a 10-inch 
crack between STA 757 and STA 767, and a 5-inch crack between STA 749 
and STA 754. This airplane had accumulated 41,899 total flight cycles. 
Both airplanes had scribe lines along the lap joints and butt joints 
and around the wing-to-body fairing. The scribe lines appear to have 
been made on the skin when sealant was removed to prepare the airplane 
for repainting.
    Analysis of the cracked skin areas confirmed that the cracks 
initiated at multiple sites along the scribe lines, which were 0.002 to 
0.004 inch deep. The first airplane accumulated 5,500 flight cycles 
between crack initiation

[[Page 22273]]

and a full-thickness crack; the second airplane accumulated 6,000 
flight cycles during this period.
    Scribe lines, if not corrected, could result in fatigue cracks that 
could grow large enough to allow rapid decompression of the airplane.
    The configuration of the fuselage is the same on Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes. Therefore, all these 
models may be subject to the identified unsafe condition.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004. The service bulletin describes procedures for a 
detailed inspection for scribe lines in the fuselage skin at certain 
lap joints, butt joints, external repair doublers, scuff plates and 
repairs in the restricted zones around the door cutouts, and, if 
affected, the skin around the wing-to-body fairing. The service 
bulletin specifies the following corrective actions:
     Blending scribe lines that are within specified limits.
     Repairing scribe lines or completing a limited return-to-
service (LRTS) program for scribe lines that exceed specified limits. 
The LRTS includes various repetitive inspections (ultrasonic, eddy 
current, substructure, internal detailed stringer inspections) for 
cracks in the area of the scribe lines.
     Contacting Boeing for crack repair instructions.
    The inspection areas are divided into three zones, which specify 
locations and corresponding potential fatigue thresholds. Because of 
the complexity of the actions and the workload for affected operators, 
the service bulletin provides instructions for calculating separate 
inspection thresholds based on fatigue life of each zonal area. By 
defining criticality of location, the service bulletin addresses the 
most critical areas (i.e., Zone 1) first and provides longer compliance 
times for less critical areas (i.e., Zones 2 and 3). The service 
bulletin provides compliance charts, based on the zonal information, 
for determining the initial scribe line inspection thresholds. The 
initial inspection could be required as early as 4,500 flight cycles 
(for airplanes with modified lap splices) or 1,200 flight cycles (for 
airplanes with unmodified lap splices) after the effective date of the 
AD. The service bulletin also describes acceptable conditions for 
exemption from the inspection.

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 accomplishing the actions specified in the service 
information described previously, except as discussed below. The 
proposed AD would also require sending the inspection results of 
positive crack findings to Boeing.

Differences Between the Proposed AD and the Service Bulletin

    The service bulletin (in Part 14) provides procedures for scribe 
lines found before the initial inspection threshold. This proposed AD 
would not require those procedures but would require only the directed 
inspection program (Parts 1 through 11). This proposed AD would allow 
the optional accomplishment of an LRTS program (in Parts 12 and 13), 
under certain conditions, to allow temporary return to service.
    This proposed AD would require operators to report cracks found 
during the inspections. While the service bulletin does not explicitly 
direct operators to provide such a report, Boeing advises that the data 
from these reports will help in the ongoing efforts to improve the 
scribe line inspection program.
    The service bulletin specifies compliance times relative to the 
date of issuance of the service bulletin; however, this proposed AD 
would require compliance before the specified compliance time relative 
to the effective date of the AD.
    The service bulletin specifies that operators may contact the 
manufacturer for instructions on how to repair certain conditions, but 
this proposed AD would require repair in one of the following ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the Boeing Delegation Option Authorization Organization whom we 
have authorized to make those findings.
    We have coordinated these different requirements with Boeing.

Costs of Compliance

    There are about 3,132 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.

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                 Number of
                                                                                                        Average      Cost per      U.S.-
                     Zone                                        Action                   Work hours  labor rate/    airplane    registered   Fleet cost
                                                                                                          hour                   airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.............................................  Sealant removal........................           66          $65       $4,290        1,384   $5,937,360
                                                Inspection.............................            4           65          260        1,384      359,840
2.............................................  Sealant removal........................           38           65        2,470        1,384    3,418,480
                                                Inspection.............................           29           65        1,885        1,384    2,608,840
3.............................................  Sealant removal........................           88           65        5,720        1,384    7,916,480
                                                Inspection.............................           38           65        2,470        1,384    3,418,480
--------------------------------------------------------------------------------------------------------------------------------------------------------

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 22274]]

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

Boeing: Docket No. FAA-2005-20918; Directorate Identifier 2004-NM-
269-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by June 13, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 737-100, -200, -200C, -
300, -400, and -500 series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD was prompted by reports of fuselage skin cracks 
adjacent to the skin lap joints on airplanes that had scribe lines. 
Scribe line damage can also occur at many other locations, including 
butt joints, external doublers, door scuff plates, the wing-to-body 
fairing, and areas of the fuselage where decals have been applied or 
removed. We are issuing this AD to prevent rapid decompression of 
the airplane due to fatigue cracks resulting from scribe lines on 
pressurized fuselage structure.

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.

Inspection

    (f) Do a detailed inspection for scribe lines and cracks in the 
fuselage skin at certain lap joints, butt joints, external repair 
doublers, and other areas, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004, except as provided by paragraph (g) of this AD. Do 
the actions at the time specified in paragraph 1.E., ``Compliance,'' 
of the service bulletin, except as required by paragraph (i) of this 
AD. Acceptable inspection exemptions are described in paragraph 
1.E.1. of Boeing Alert Service Bulletin 737-53A1262.
    (1) If no scribe line is found, no further work is required by 
this AD.
    (2) If any scribe line is found: Do all applicable investigative 
and corrective actions at the time specified by doing all applicable 
actions specified in the Accomplishment Instructions of the service 
bulletin, except as required by paragraph (h) of this AD.

    Note 1: A detailed inspection is defined in Note 10 of Boeing 
Alert Service Bulletin 737-53A1262 under 3.A., ``General 
Information.'' Specific magnification requirements may be specified 
in the steps of the Work Instructions.

Exceptions to Service Bulletin Procedures

    (g) This AD requires accomplishment of Parts 1 through 11 of 
Boeing Alert Service Bulletin 737-53A1262. Parts 12 and 13 of the 
service bulletin may be accomplished, if applicable, to allow 
temporary return to service. This AD does not require accomplishment 
of Part 14 of the service bulletin.
    (h) If any scribe line or crack is found during any inspection 
required by this AD, and the service bulletin specifies to contact 
Boeing for appropriate action: Before further flight, repair 
according to a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA; or according to data meeting the 
certification basis of the airplane approved by an Authorized 
Representative for the Boeing 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 
approval must specifically refer to this AD.
    (i) Where the service bulletin specifies a compliance time after 
the issuance of the service bulletin, this AD requires compliance 
within the specified compliance time after the effective date of 
this AD.

Reporting Requirement

    (j) At the applicable time specified in paragraph (j)(1) or 
(j)(2) of this AD, submit a report of positive findings of cracks 
found during the inspection required by paragraph (f) of this AD to 
the Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. Alternatively, operators may submit reports 
to their Boeing field service representatives. The report shall 
contain, as a minimum, the following information: airplane serial 
number, flight cycles at time of discovery, location(s) and extent 
of positive crack findings. Under the provisions of the Paperwork 
Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office of 
Management and Budget (OMB) has approved the information collection 
requirements contained in this AD and has assigned OMB Control 
Number 2120-0056.
    (1) If the inspection was done before the effective date of this 
AD: Send the report within 30 days after the effective date of this 
AD.
    (2) If the inspection was done after the effective date of this 
AD: Send the report within 30 days after the inspection is done.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle 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) 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 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 approval must specifically refer to this AD.

    Issued in Renton, Washington, on April 19, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-8578 Filed 4-28-05; 8:45 am]
BILLING CODE 4910-13-P