[Federal Register: April 18, 2006 (Volume 71, Number 74)]
[Proposed Rules]
[Page 19835-19838]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18ap06-17]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
[Docket No. FAA-2006-24496; Directorate Identifier 2005-NM-141-AD]
14 CFR Part 39
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 inspections
to detect cracks in the vertical beam webs of the body station (BS) 178
bulkhead, and corrective actions if necessary. This proposed AD also
would require a terminating modification for the repetitive
inspections. This proposed AD results from reports of numerous cracks
in the vertical beam webs. We are proposing this AD to prevent fatigue
cracks in certain vertical beam webs, which could result in loss of
structural integrity of the BS 178 bulkhead, and consequently could
impair the operation of the control cables for the elevators, speed
brakes, and landing gear, or could cause the loss of cabin pressure.
DATES: We must receive comments on this proposed AD by June 2, 2006.
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.
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.
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 98055-4056; 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-2006-
24496; Directorate Identifier 2005-NM-141-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
[[Page 19836]]
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 Docket Management System receives them.
Discussion
We have received several reports of numerous cracks in the vertical
beam webs at buttock lines (BL) 5.7 and 17.0 of the body station (BS)
178 bulkhead on Boeing Model 737-100, -200, -200C, -300, -400, and -500
series airplanes, line numbers 1 through 3132 inclusive. Five cracks
nearly severed the upper web of the BL 17.0 vertical beam. One crack
severed the lower web of the BL 17.0 vertical beam. The cracks initiate
from holes in the web of the vertical beams and at fastener locations
common to the forward and aft chords of the vertical beams. These
airplanes have accumulated between 15,556 and 64,881 total flight
cycles. The cracks occur as a result of structural fatigue due to cabin
pressure loads. Fatigue cracks in the vertical beam webs at BL 5.7 and
17.0 of BS 178 bulkhead, if not detected and corrected, could result in
loss of structural integrity of the bulkhead, which could impair the
operation of the control cables for the elevators, speed brakes, and
landing gear, or could cause the loss of cabin pressure.
Other Relevant Rulemaking
We have previously issued AD 2000-05-29, amendment 39-11639 (65 FR
14834, March 20, 2000), applicable to Boeing Model 737-100, -200, -300,
-400, and -500 series airplanes, line numbers 1 through 2,737
inclusive. That AD requires repetitive inspections to detect fatigue
cracking of the web, vertical chords, and side chords of the forward
pressure bulkhead, and repair if necessary. That AD also provides for
certain optional preventative modifications (reference Boeing Alert
Service Bulletin 737-53A1173, Revision 3, dated May 6, 1999), which, if
done, ends the repetitive inspection requirements for the affected
areas.
In addition, we have previously issued AD 2001-02-01, amendment 39-
12085 (66 FR 7576, January 24, 2001), applicable to Boeing Model 737-
300, -400, and -500 series airplanes, line numbers 2,738 through 3,071
inclusive. That AD requires repetitive inspections to detect fatigue
cracking in the vertical chords and side chords of the forward pressure
bulkhead, and repair if necessary. That AD also requires certain
preventative modifications (reference Boeing Alert Service Bulletin
737-53A1208, dated May 6, 1999), which ends the repetitive inspection
requirements for the affected areas.
For certain airplanes, accomplishing the preventative modification
in this proposed AD may affect accomplishing the preventative
modifications specified as optional in AD 2000-05-29 and required by AD
2001-02-01. See ``Effect of Accomplishing Concurrent Requirements''
section for further information.
Relevant Service Information
We have reviewed Boeing Service Bulletin 737-53A1225, Revision 1,
dated April 14, 2005. The service bulletin describes procedures for
repetitive high frequency eddy current (HFEC) and detailed inspections
to detect cracks in the BS 178 vertical beam webs, and corrective
actions if necessary. The corrective actions include repairing or
replacing any cracked vertical beam web and associated parts with a new
vertical beam web and associated parts. The service bulletin also
describes procedures for a preventative modification (i.e., repairing
or replacing the vertical beams at BL 5.7 and 17.0 of the BS 178
bulkhead), which ends the repetitive inspections. For certain
airplanes, Boeing Service Bulletin 737-53A1225 recommends accomplishing
concurrently the terminating preventative modifications specified in
Boeing Alert Service Bulletin 737-53A1173 or 737-53A1208, as
applicable, due to common access and structure.
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 Proposed AD and Service Information
Boeing Service Bulletin 737-53A1225 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.
Effect of Accomplishing Concurrent Requirements
Operators who have not done the preventative modifications
specified in AD 2000-05-29 (reference Boeing Alert Service Bulletin
737-53A1173, Revision 3, dated May 6, 1999) or required by AD 2001-02-
01 (reference Boeing Alert Service Bulletin 737-53A1208, dated May 6,
1999), as applicable, as of the effective date of this AD, must do
those preventative modifications concurrently with the preventative
modification of this proposed AD in accordance with Boeing Service
Bulletin 737-53A1225, Revision 1. We realize that the concurrent
requirements of this proposed AD will force some operators to do the
preventative modifications required by AD 2001-02-01 early and to do
the optional preventative modification specified in AD 2000-05-29.
However, accomplishing the applicable preventative modifications
together is necessary to avoid repeated disassembly and re-assembly of
common parts, which increases the likelihood of additional assembly
errors.
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.
[[Page 19837]]
Estimated Costs
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Average
Action Work hours labor rate Parts Cost per airplane Number of U.S.- Fleet cost
per hour registered airplanes
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Inspection, per inspection cycle.. 4 $80 None................. $320, per inspection 1,172................ $375,040, per
cycle. inspection cycle.
Preventative Modification......... 240 80 Between $960 and Between $20,160 and 1,172 (720 airplanes Between $14,515,200
$13,620 depending on $32,820 depending on have had the and $23,630,400.
kit purchased. configuration. preventative
modification
incorporated).
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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 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-2006-24496; Directorate Identifier 2005-NM-
141-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by June 2,
2006.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-100, -200, -200C, -300,
-400, -500 series airplanes, certificated in any category; as
identified in Boeing Service Bulletin 737-53A1225, Revision 1, dated
April 14, 2005.
Unsafe Condition
(d) This AD results from reports of numerous cracks in the
vertical beam webs. We are issuing this AD to prevent fatigue cracks
in certain vertical beam webs, which could result in loss of
structural integrity of the body station (BS) 178 bulkhead, and
consequently could impair the operation of the control cables for
the elevators, speed brakes, and landing gear, or could cause the
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) At the applicable times specified in Table 1 of this AD, do
a high frequency eddy current (HFEC) inspection and detailed
inspection to detect cracks in the BS 178 vertical beam webs, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-53A1225, Revision 1, dated April 14, 2005.
Table 1.--Compliance Times
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And repeat the
HFEC and
For airplanes on which-- Inspect-- detailed
inspections
thereafter at--
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(1) An HFEC or a detailed Before the Intervals not to
inspection specified in accumulation of exceed 6,000
Boeing Service Bulletin 737- 15,000 total flight flight cycles.
53A1225, dated October 19, cycles, or within
2000, has not been done as of 4,500 flight cycles
the effective date of this AD. after the effective
date of this AD,
whichever occurs
later.
(2) An HFEC or detailed Within 6,000 flight Intervals not to
inspection specified in cycles since the last exceed 6,000
Boeing Service Bulletin 737- HFEC inspection, or flight cycles.
53A1225, dated October 19, within 1,200 flight
2000, has been done before cycles since the last
the effective date of this AD. detailed inspection,
whichever occurs
later.
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[[Page 19838]]
Corrective Actions
(g) If any crack is detected during any inspection required by
paragraph (f) of this AD, before further flight, repair or replace
the vertical beam web and associated parts with a new vertical beam
web, in accordance with the Accomplishment Instructions of Boeing
Service Bulletin 737-53A1225, Revision 1, dated April 14, 2005,
except as provided by paragraph (h) of this AD.
(h) If any damage is beyond the scope of the service bulletin or
structural repair manual, before further flight, repair the damaged
vertical beam web in accordance with a method approved by the
Manager, Seattle Aircraft Certification Office (ACO), FAA; or using
a method approved in accordance with paragraph (l) of this AD.
Terminating Preventative Modification
(i) Before the accumulation of 50,000 total flight cycles, or
within 25,000 flight cycles after the effective date of this AD,
whichever occurs later, repair or replace the vertical beams at
buttock lines (BL) 5.7 and 17.0 of the BS 178 bulkhead, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-53A1225, Revision 1, dated April 14, 2005.
Accomplishing the repair or replacement ends the repetitive
inspections required by paragraph (f) of this AD.
(j) Actions done before the effective date of this AD in
accordance with Boeing BOECOM M-7200-01-00546, dated March 1, 2001,
are acceptable for compliance with the requirements of paragraph (i)
of this AD.
Concurrent Requirements
(k) For Group 1 airplanes identified in Boeing Service Bulletin
737-53A1225, Revision 1, dated April 14, 2005: Concurrently with the
requirements of paragraph (i) of this AD, unless already done before
the effective date of this AD, do the preventative modifications of
the center web, vertical chords, and side chord areas, including the
side chord areas at water line 207, of the forward pressure
bulkhead, specified in paragraph (c) of AD 2000-05-29, amendment 39-
11639 (reference Boeing Alert Service Bulletin 737-53A1173, Revision
3, dated May 6, 1999).
(l) For Group 2 airplanes identified in Boeing Service Bulletin
737-53A1225, Revision 1, dated April 14, 2005: Concurrently with the
requirements of paragraph (i) of this AD, but no later than the time
specified in AD 2001-02-01, amendment 39-12085, do the preventative
modifications of the vertical and side chord areas of the forward
pressure bulkhead required by paragraph (c) of AD 2001-02-01
(reference Boeing Alert Service Bulletin 737-53A1208, dated May 6,
1999).
Alternative Methods of Compliance (AMOCs)
(m)(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) Before using any AMOC approved in accordance with Sec.
39.19 on any airplane to which the AMOC applies, notify the
appropriate principal inspector in the FAA Flight Standards
Certificate Holding District Office.
(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 April 4, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E6-5723 Filed 4-17-06; 8:45 am]
BILLING CODE 4910-13-P