[Federal Register: October 11, 2007 (Volume 72, Number 196)]
[Proposed Rules]
[Page 57890-57892]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11oc07-19]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0024; Directorate Identifier 2007-NM-086-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 all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. This proposed AD would require repetitive inspections for
cracking in and around the upper and lower hinge cutouts of the forward
entry and forward galley service doorways, and corrective actions if
necessary. This proposed AD results from multiple reports of cracks
found in the skin, bearstrap, and/or frame outer chord in the hinge
cutout areas of the forward entry and forward galley service doorways.
We are proposing this AD to detect and correct such cracking, which
could result in rapid decompression of the airplane.
DATES: We must receive comments on this proposed AD by November 26,
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: Howard Hall, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6430; 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 in the ADDRESSES section. Include the docket number ``FAA-2007-
0024; Directorate Identifier 2007-NM-086-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 multiple reports of cracks found in the skin,
bearstrap, and/or frame outer chord in the hinge cutout areas of the
forward entry and forward galley service doorways. Cracks in the
forward entry door bearstrap were reported on an airplane with as few
as
[[Page 57891]]
24,538 total flight cycles. Cracks in the forward galley service door
bearstrap were reported on an airplane with as few as 44,938 total
flight cycles. One operator reported a severed bearstrap, a severed
station (STA) 291.5 frame, and a 14.5-inch crack in the skin at the
lower hinge cutout of the forward galley service doorway. The airplane
had accumulated 61,297 total flight cycles. Such cracking, if not
corrected, could result in rapid decompression of the airplane.
The fatigue cracks are caused by cyclic cabin pressure loads and
are not due to manufacturing defects in the bearstrap. The unsafe
condition is unrelated to any previous investigation related to
suspected unapproved parts.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 737-53A1200, dated
April 13, 2006. The service bulletin describes procedures for
repetitive inspections for cracking in and around the upper and lower
hinge cutouts of the forward entry and forward galley service doorways.
The service bulletin describes the following inspections:
External detailed inspection of the skin;
High frequency eddy current (HFEC) hole probe inspection
of the skin, bonded doubler, bearstrap, and frame chord at specified
fastener locations;
HFEC hole probe inspection of the skin, bonded doubler,
and bearstrap at specified fastener locations aft of the frame chord;
HFEC inspection of the skin hinge cutout trim;
Low frequency eddy current (LFEC) hole probe inspection of
the skin, bonded doubler, and bearstrap at specific fastener locations
aft of the frame chord;
LFEC hole probe inspection of the skin, bonded doubler,
bearstrap, and frame chord at specific fastener locations.
The service bulletin provides two options for the inspections, as
follows:
Compliance Times
----------------------------------------------------------------------------------------------------------------
Repetitive
Option Inspections Threshold, in total Grace period, in interval, in
flight cycles flight cycles flight cycles
----------------------------------------------------------------------------------------------------------------
A \1\................ External detailed Entry door: 20,000..... 3,000 18,000
inspection; HFEC inspection Service door: 40,000...
of the skin hinge cutout
trim; and HFEC rotary probe
inspection of the entire
zone.
B.................... External detailed Entry door: 20,000..... 3,000 3,000
inspection; HFEC inspection Service door: 40,000...
of the skin hinge cutout
trim; and LFEC inspection
of the entire zone.
いいいいいいいいいいい
HFEC rotary probe inspection Entry door: 20,000..... 6,000 18,000
of the aft zone (required Service door: 40,000...
only for Group 1,
Configuration 1, and only
for the entry door).
----------------------------------------------------------------------------------------------------------------
\1\ Option A is mandatory for the forward entry door, upper and lower hinge cutouts, on Model 737-200C
airplanes.
The service bulletin specifies contacting Boeing for crack repair
instructions.
The service bulletin also states that the service bulletin might in
the future be revised to include a preventive modification that will
eliminate the need for the repetitive inspections. The service bulletin
specifies contacting Boeing for information about this modification.
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, except as discussed below.
Difference Between the Proposed AD and the Service Bulletin
The service bulletin specifies contacting the manufacturer for
instructions for crack repair and for an optional modification that
would terminate the repetitive inspections. But this proposed AD would
require doing the repair and optional modification 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 Commercial Airplanes Delegation Option Authorization
Organization whom we have authorized to make those findings.
Costs of Compliance
There are about 2,437 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, per inspection cycle.
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Number of U.S.-
Work hours Average hourly Cost per airplane registered Fleet cost
labor rate airplanes
----------------------------------------------------------------------------------------------------------------
13 to 14.......................... $80 $1,040 to $1,120.... 1,055 $1,097,200 to
$1,181,600
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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
[[Page 57892]]
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 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-2007-0024; Directorate Identifier 2007-NM-
086-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by November
26, 2007.
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 results from multiple reports of cracks found in the
skin, bearstrap, and/or frame outer chord in the hinge cutout areas
of the forward entry and forward galley service doorways. We are
issuing this AD to detect and correct such cracking, which could
result in rapid decompression of the airplane.
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.
Repetitive Inspections
(f) Except as provided by paragraph (g) of this AD, at the
applicable times specified in paragraph 1.E. of Boeing Alert Service
Bulletin 737-53A1200, dated April 13, 2006, do external detailed,
low frequency eddy current, high frequency eddy current, and high
frequency eddy current rotary probe inspections, as applicable, for
cracks in and around the upper and lower hinge cutouts of the
forward entry and forward galley service doorways, in accordance
with the Accomplishment Instructions of the service bulletin, except
as provided by paragraph (h) of this AD. Do not exceed the
applicable repetitive interval for the previous inspection, as
specified in the service bulletin as Option A or Option B. Repair
any crack before further flight using a method approved in
accordance with the procedures specified in paragraph (i) of this
AD.
Exceptions to Service Bulletin Specifications
(g) Where the service bulletin specifies a compliance time after
the release date of the service bulletin, this AD requires
compliance within the specified compliance time after the effective
date of this AD.
(h) Although the service bulletin specifies contacting Boeing
for information about installing an optional preventive modification
that would terminate the repetitive inspections specified in this
AD, this AD requires that any terminating action be done by using a
method approved in accordance with the procedures specified in
paragraph (i) of this AD.
Alternative Methods of Compliance (AMOCs)
(i)(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 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 October 1, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-20048 Filed 10-10-07; 8:45 am]
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