[Federal Register: April 29, 2005 (Volume 70, Number 82)]
[Proposed Rules]
[Page 22272-22274]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29ap05-15]
========================================================================
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.
========================================================================
[[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