[Federal Register: November 26, 2007 (Volume 72, Number 226)]
[Proposed Rules]
[Page 65909-65911]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26no07-9]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0228; Directorate Identifier 2007-NM-107-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-200 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 737-200 series airplanes. This proposed AD
would require repetitive inspections to detect cracking of the support
fittings of the Krueger flap actuators, and corrective actions if
necessary. This proposed AD also would require eventual replacement of
any existing aluminum support fitting on each wing with a steel
fitting, and modification of the aft attachment of the actuator. Doing
these actions would terminate the repetitive inspection requirements.
This proposed AD results from reports of cracking due to fatigue and
stress corrosion of the support fittings of the Krueger flap actuator.
We are proposing this AD to prevent cracking of the support fittings,
which could result in fracturing of the actuator attach lugs,
separation of the actuator from the support fitting, severing of the
hydraulic lines, resultant loss of hydraulic fluids, and consequent
reduced controllability of the airplane.
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-2007-0228;
Directorate Identifier 2007-NM-107-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
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 reports of cracks in the support fitting of the
Krueger flap actuator mounted on the front spar of eight affected
airplanes. On one airplane, the lugs on the No. 1 Krueger flap actuator
support fitting severed completely, the actuator separated from the
front spar, and the hydraulic lines were severed. On another airplane,
both actuator attach lugs of a No. 1 flap support fitting were also
completely severed. The cracking is attributed to fatigue and stress
corrosion, and it is suspected that high clamp-up stresses may be
contributing to cracks in the actuator attach lugs. Cracking of the
support fittings, if not corrected, could result in fracturing of the
actuator attach lugs, separation of the actuator from the support
fitting, severing of the hydraulic lines, resultant loss of hydraulic
fluids, and consequent reduced controllability of the airplane.
Other Relevant Rulemaking
On July 31, 2000, we issued AD 2000-15-18, amendment 39-11851 (65
FR 48371, August 8, 2000). That AD applies to certain Boeing Model 737-
100 and -200 series airplanes, line numbers 001 through 813 inclusive.
That AD requires inspections to detect cracking of the support fittings
of the Krueger flap actuator; and, if necessary, replacement of
existing fittings with new steel fittings and modification of the aft
attachment of the actuator. That AD also requires eventual replacement
of any existing aluminum Krueger flap actuator support fitting on each
wing with a steel fitting, which terminates the repetitive inspection
requirements. That AD resulted from reports of cracking due to fatigue
and stress corrosion of the support fittings of the Krueger flap
actuator. The actions in that AD are intended to prevent such cracking,
which could result in fracturing of the actuator attach lugs,
separation of the actuator from the support fitting, severing of the
hydraulic lines, and
[[Page 65910]]
resultant loss of hydraulic fluids. These conditions, if not corrected,
could result in possible failure of one or more hydraulic systems, and
consequent reduced controllability of the airplane.
Since we issued AD 2000-15-18, we have determined that the same
unsafe condition addressed in that AD exists on certain additional
Model 737-200 series airplanes. We were advised that Model 737-200
series airplanes, line numbers 814 through 826 inclusive, are also
subject to the same unsafe condition addressed in AD 2000-15-18.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletin 737-57-
1129, Revision 3, dated March 19, 2007. The service bulletin describes
procedures for repetitive high frequency eddy current (HFEC)
inspections to detect cracking of the support fittings of the Krueger
flap actuators, and corrective actions if necessary. The corrective
actions are replacement of existing fittings with new steel fittings
and modification of the aft attachment of the actuator. This
replacement and modification eliminates the need for the repetitive
inspection requirements. 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.
Costs of Compliance
There are about 13 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
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Number of U.S.-
Action Work hours Average labor Parts Cost per airplane registered Fleet cost
rate per hour airplanes
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Inspection........................... 5 $80 $0 $400, per inspection 3 $1,200, per inspection
cycle. cycle.
Replacement.......................... 88 $80 $29,642 $36,682................. 3 $110,046.
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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-2007-0228; Directorate Identifier 2007-NM-
107-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 737-200 series airplanes,
line numbers 814 through 826 inclusive, certificated in any
category.
Unsafe Condition
(d) This AD results from reports of cracking due to fatigue and
stress corrosion of the support fittings of the Krueger flap
actuator. We are issuing this AD to prevent cracking of the support
fittings, which could result in fracturing of the actuator attach
lugs, separation of the actuator from the support fitting, severing
of the hydraulic lines, resultant loss of hydraulic fluids, and
consequent reduced controllability 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) Within 12 months after the effective date of this AD, do a
high frequency eddy current (HFEC) inspection to detect cracking of
the support fittings of the Krueger flap actuator on each wing, in
accordance with the Accomplishment Instructions of Boeing Special
Attention Service Bulletin 737-57-1129, Revision 3, dated March 19,
2007.
[[Page 65911]]
(1) If no cracking is detected, repeat the inspection thereafter
at intervals not to exceed 3,000 flight hours until the terminating
action required by paragraph (g) of this AD is accomplished.
(2) If any cracking is detected, before further flight, do the
replacement and modification specified in paragraph (g) of this AD.
Terminating Action
(g) Within 60 months after the effective date of this AD:
Replace any existing Krueger flap actuator aluminum support fitting
on each wing with a steel fitting, and modify the actuator aft
attachment, in accordance with the Accomplishment Instructions of
Boeing Special Attention Service Bulletin 737-57-1129, Revision 3,
dated March 19, 2007. Doing this replacement and modification
terminates the repetitive inspection requirements of paragraph (f)
of this AD.
Parts Replacement
(h) As of the effective date of this AD, no person may install
on any airplane any aluminum support fitting (actuator support
assembly) identified in the ``Existing Part Number'' column of
paragraph 2.C. of Boeing Special Attention Service Bulletin 737-57-
1129, Revision 3, dated March 19, 2007.
Actions Accomplished in Accordance With Previous Revisions of Service
Bulletin
(i) Actions done before the effective date of this AD in
accordance with the service bulletins listed in Table 1 of this AD,
are acceptable for compliance with the corresponding requirements of
this AD.
Table 1.--Previous Revisions of Service Bulletins
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Boeing service bulletin Revision level Date
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737-57-1129........................... 1.................................. October 30, 1981.
737-57-1129........................... 2.................................. May 28, 1998.
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Alternative Methods of Compliance (AMOCs)
(j)(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 November 13, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-22926 Filed 11-23-07; 8:45 am]
BILLING CODE 4910-13-P