[Federal Register: November 26, 2007 (Volume 72, Number 226)]
[Proposed Rules]
[Page 65911-65913]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26no07-10]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0224; Directorate Identifier 2007-NM-188-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -300, -400,
and -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 certain Boeing Model 737-100, -200, -300, -400, and -500 series
airplanes. This proposed AD would require repetitive inspections for
fatigue cracking in the longitudinal floor beam web, upper chord, and
lower chord located at certain body stations, and repair if necessary.
This proposed AD results from several reports of cracks in the center
wing box longitudinal floor beams, upper chord, and lower chord. We are
proposing this AD to detect and correct fatigue cracking of the upper
and lower chords and web of the longitudinal floor beams, which could
result in rapid loss of cabin pressure.
DATES: We must receive comments on this proposed AD by January 10,
2008.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov.
Follow the instructions for submitting comments.
Fax: 202-493-2251.
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.
Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this AD, contact Boeing
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov
; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (telephone 800-647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.
FOR FURTHER INFORMATION CONTACT: Nancy Marsh, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6440; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2007-0224;
Directorate Identifier 2007-NM-188-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
[[Page 65912]]
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov
, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
Discussion
We have received several reports of fatigue cracks in the center
wing box longitudinal floor beams on certain Boeing Model 737-100, -
200, -300, -400, and -500 series airplanes. The cracks were found in
the longitudinal floor beam web, upper chord, and lower chord at left
buttock line (LBL) 24.8, right buttock line (RBL) 24.8, LBL 45.5 and
RBL 45.5, between Station (STA) 656 and STA 727B. The airplanes had
accumulated between 17,000 and 70,000 total flight cycles. These
fatigue cracks are attributed to cyclic pressurization loads, fuel
loads, and passenger loads. Fatigue cracking of the upper and lower
chords and web of the longitudinal floor beams, if not corrected, could
result in rapid loss of cabin pressure.
Related Rulemaking
On December 30, 1998, we issued AD 98-11-04 R1, amendment 39-10984
(64 FR 987) applicable to Boeing Model 737-100 and -200 series
airplanes. That AD requires revising the FAA-approved maintenance
program to include inspections that will give no less than the required
damage tolerance rating for each structural significant item (SSI) if
they are not effective for the SSI, and repair of cracked structure.
Certain actions in this proposed AD are considered alternative methods
of compliance (AMOCs) for paragraphs (b) and (c) of AD 98-11-04 R1.
Relevant Service Information
We have reviewed Boeing Service Bulletin 737-57-1296, dated June
13, 2007. The service bulletin describes procedures for the following:
Detailed inspections for any crack in the upper chord of
the longitudinal floor beam at LBL 24.8 and RBL 24.8, between STA 656
and STA 685.
High frequency eddy current inspections for any crack in
the lower chord of the longitudinal floor beam at LBL 24.8 and RBL
24.8, between STA 660 and STA 666.
Detailed inspections for any crack in the longitudinal
floor beam web at LBL 24.8, RBL 24.8, LBL 45.5, and RBL 45.5, between
STA 705 and STA 715.
Detailed inspections for any crack in the horizontal
flange of the upper chord of the longitudinal floor beam at LBL 24.8,
RBL 24.8, LBL 45.5, and RBL 45.5, at STA 727B.
The compliance times specified are as follows:
For Groups 1 and 2 airplanes: Before the accumulation of 20,000
total flight cycles, or within 6,000 flight cycles after the service
bulletin date, whichever occurs later. Repeat the inspections
thereafter at intervals not to exceed 6,000 flight cycles.
For Group 3 airplanes: Before the accumulation of 20,000 total
flight cycles, or within 7,000 flight cycles after the service bulletin
date, whichever occurs later. Repeat the inspections thereafter at
intervals not to exceed 7,000 flight cycles.
If a crack is found, the service bulletin recommends contacting
Boeing before further flight for repair instructions. If no crack is
found, the procedures in the service bulletin specify repeating the
inspections. 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, except as discussed under
``Difference Between the Proposed AD and Service Information.''
Difference Between the Proposed AD and Service Information
The service bulletin specifies to contact the manufacturer for
instructions on how to repair certain conditions, but this proposed AD
would require repairing those conditions 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 2,852 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 652 airplanes of
U.S. registry. The proposed inspection would take approximately 13 work
hours per airplane, at an average labor rate of $80 per work hour.
Based on these figures, the estimated cost of the proposed inspection
for U.S. operators is $678,080, or $1,040 per airplane, per inspection
cycle.
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 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.
[[Page 65913]]
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-2007-0224; Directorate Identifier 2007-NM-
188-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by January
10, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-100, -200, -300, -400,
and -500 series airplanes, certificated in any category; as
identified in Boeing Service Bulletin 737-57-1296, dated June 13,
2007.
Unsafe Condition
(d) This AD results from several reports of cracks in the center
wing box longitudinal floor beams, upper chord, and lower chord. We
are issuing this AD to detect and correct fatigue cracking of the
upper and lower chords and web of the longitudinal floor beams,
which could result in rapid 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.
Repetitive Inspections
(f) Do the various inspections for fatigue cracks in the
longitudinal floor beam web, upper chord, and lower chord, located
at the applicable body stations specified in the Accomplishment
Instructions of Boeing Service Bulletin 737-57-1296, dated June 13,
2007, by doing all the actions specified in the Accomplishment
Instructions of the service bulletin, except as provided by
paragraph (g) of this AD. Do the inspections at the time specified
in paragraph (f)(1) or (f)(2) of this AD, as applicable.
(1) For Groups 1 and 2 airplanes as identified in the service
bulletin: Do the inspections at the applicable initial compliance
time listed in paragraph 1.E., ``Compliance,'' of the service
bulletin; except, where the service bulletin specifies a compliance
time after the date on the service bulletin, this AD requires
compliance within the specified compliance time after the effective
date of this AD. Repeat the inspections thereafter at the intervals
specified in paragraph 1.E., ``Compliance,'' of the service
bulletin.
(2) For Group 3 airplanes as identified in the service bulletin:
Do the inspections at the applicable initial compliance time listed
in paragraph 1.E., ``Compliance,'' of the service bulletin; except,
where the service bulletin specifies a compliance time after the
date on the service bulletin, this AD requires compliance within the
specified compliance time after the effective date of this AD.
Repeat the inspections thereafter at the intervals specified in
paragraph 1.E., ``Compliance,'' of the service bulletin.
(g) If any crack is found during any inspection required by this
AD, and Boeing Service Bulletin 737-57-1296, dated June 13, 2007,
specifies contacting Boeing for repair instructions: Before further
flight, repair using a method approved in accordance with the
procedures specified in paragraph (h) of this AD.
Alternative Methods of Compliance (AMOCs)
(h)(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) 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.
Issued in Renton, Washington, on November 13, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-22928 Filed 11-23-07; 8:45 am]
BILLING CODE 4910-13-P