[Federal Register: October 22, 2008 (Volume 73, Number 205)]
[Proposed Rules]
[Page 62937-62940]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr22oc08-23]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-1116; Directorate Identifier 2007-NM-231-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. For certain airplanes, this proposed AD would require
deactivation or modification of the wiring to the outboard landing
lights, until the wire bundles and electrical connectors have been
replaced. For all airplanes, this proposed AD would also require an
inspection for any broken, damaged, or missing fairleads, grommets, and
wires in the four electrical junction boxes of the main wheel well, and
corrective actions if necessary. For certain airplanes, this proposed
AD would also require replacement of certain wire bundles for the
landing lights and fuel shutoff valves, and related investigative,
other specified, and corrective actions if necessary. For certain
airplanes, this proposed AD would also require replacement of certain
electrical connectors and backshell clamps. This proposed AD results
from reports of uncommanded engine shutdowns and burned and damaged
wire bundles associated with the outboard landing lights and engine
fuel shutoff valves. This proposed AD also results from reports of
damaged and missing grommets and broken and damaged fairleads in the
electrical junction boxes of the main wheel well. We are proposing this
AD to prevent a hot short between the outboard landing light and fuel
shutoff valve circuits, which could result in an uncommanded engine
shutdown. We are also proposing this AD to prevent corrosion of the
electrical connectors of the wing rear spars, which could result in
short circuits and consequent incorrect functioning of airplane systems
needed for safe flight and landing.
DATES: We must receive comments on this proposed AD by December 8,
2008.
ADDRESSES: You may send comments by any of the following methods:
[[Page 62938]]
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: Stephen Oshiro, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6480; 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-2008-1116;
Directorate Identifier 2007-NM-231-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 uncommanded engine shutdowns and burned
and damaged wire bundles where the wire bundle exits the main wheel
well in the area of the wing rear spar on Boeing Model 737-300, -400,
and -500 series airplanes. Investigation revealed that the uncommanded
engine shutdowns were caused by uncommanded closure of the engine fuel
shutoff valves, which resulted from short circuits between the 115 volt
alternating current (VAC) circuits of the outboard landing lights and
the 28 volt direct current (VDC) circuits of the engine fuel shutoff
valves. This short circuit causes the valve to move towards the closed
position. Failure of the valve occurs shortly after reaching the closed
position due to exposure of the 28-VDC valve to 115-VAC power from the
outboard landing light circuit. The loss of ability to reopen the valve
prevents restarting the engine due to the unavailability of fuel.
Uncommanded closure of the fuel shutoff valve due to a hot short
between the outboard landing light and the fuel shutoff valve circuits,
if not corrected, could result in an uncommanded engine shutdown.
Subsequently, Boeing published Boeing Service Bulletin 737-28-1241,
dated April 7, 2006, to provide instructions for replacing certain wire
bundles with new, re-designed wire bundles to prevent short circuits
between the outboard landing light and engine fuel shutoff valve
circuits. After issuing that service bulletin, Boeing discovered that
some of the replacement wire bundles were inadvertently assembled and
delivered with electrical connectors and backshells having a cadmium-
plated finish instead of an anodized aluminum finish. The electrical
connectors and backshells are located on the rear spar of the left and
right wings. The cadmium-plated connectors and backshells corrode
quickly when exposed to potassium-based de-icing fluids. This corrosion
leads to moisture ingress into the electrical connectors and subsequent
corrosion of the electrical contacts within the electrical connectors.
This condition, if not corrected, could result in short circuits and
consequent incorrect functioning of airplane systems needed for safe
flight and landing.
We have also received reports of damaged and missing grommets and
broken and damaged fairleads in the electrical junction boxes of the
main wheel well on Boeing Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes. Although there is no evidence that these wiring
discrepancies have contributed to uncommanded engine shutdowns, the
wiring in this area includes the wire bundles for the engine fuel
shutoff valves, as well as wiring for other systems needed for
continued safe flight and landing of the airplane.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 737-33A1140, dated
May 22, 2006, for Model 737-300, -400, and -500 series airplanes. The
service bulletin specifies accomplishing the actions in either Part 1
or Part 2 of the Accomplishment Instructions. Part 1 describes
procedures for deactivating the outboard landing lights. The
deactivation includes installing collars and ``do not close'' tags on
the circuit breakers for the outboard landing lights, and capping and
stowing the wires from the circuit breakers. Part 2 describes
procedures for modifying the wiring to the outboard landing lights. The
modification includes capping and stowing the existing wires to the
outboard landing lights, and routing new wires to the outboard landing
lights.
We have also reviewed Boeing Service Bulletin 737-28-1241, Revision
1, dated August 31, 2007, for Model 737-100, -200, -200C, -300, -400,
and -500 series airplanes. Part 1 of the Accomplishment Instructions of
the service bulletin applies to certain Model 737-300, -400, and -500
series airplanes. Part 1 describes procedures for replacing certain
wire bundles for the landing lights and fuel shutoff valves with new,
re-designed wire bundles, and doing related investigative, other
specified, and corrective actions if necessary. The related
investigative actions include (1) doing a detailed inspection for any
broken, damaged, or missing grommet where the wire bundles go from the
wheel well to the wing and (2) doing a detailed inspection for any
broken, damaged, or missing fairleads, any damaged or missing grommets,
and any chafed or damaged wires or wire bundles in the electrical
junction boxes of the main wheel well. The other specified actions
include (1) removing any additional outboard landing light wires from
the wire bundles installed in accordance with Boeing Alert Service
Bulletin 737-33A1140 and (2) terminating the outboard landing lights at
the circuit breakers, as necessary. The corrective actions include (1)
replacing any broken, damaged, or missing fairlead with a new fairlead,
(2) replacing any damaged or missing grommet with a new grommet, and
(3) repairing or
[[Page 62939]]
replacing any chafed or damaged wires and wire bundles with new wires
and wire bundles.
Part 2 of the Accomplishment Instructions of Boeing Service
Bulletin 737-28-1241 describes procedures for doing a detailed
inspection for any broken, damaged, or missing fairleads, any damaged
or missing grommets, and any chafed or damaged wires or wire bundles in
the four electrical junction boxes of the main wheel well, and doing
the corrective actions as necessary.
Part 3 of the Accomplishment Instructions of Boeing Service
Bulletin 737-28-1241 applies to certain Model 737-300, -400, and -500
series airplanes on which the wire bundle replacement was done in
accordance with the original issue of the service bulletin, dated April
7, 2006. Part 3 describes procedures for replacing certain electrical
connectors and backshell clamps with new, improved electrical
connectors and backshell clamps.
Accomplishing the applicable actions specified in Boeing Service
Bulletin 737-28-1241 would end the need for accomplishing the
deactivation or modification specified in Boeing Alert Service Bulletin
737-33A1140.
Boeing Alert Service Bulletin 737-33A1140 and Boeing Service
Bulletin 737-28-1241 specify prior or concurrent accomplishment of
Boeing Special Attention Service Bulletin 737-28-1196, dated December
5, 2002; Revision 1, dated March 13, 2003; Revision 2, dated August 21,
2003; or Revision 3, dated April 1, 2004. Boeing Special Attention
Service Bulletin 737-28-1196 describes procedures for changing the wire
connections for the engine fuel shutoff valves and the outboard landing
lights.
FAA's Determination and Requirements of This Proposed AD
We are proposing this AD because we evaluated all relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the(se) same type
design(s). This proposed AD would require the following actions:
For Model 737-300, -400, and -500 series airplanes,
deactivation or modification of the wiring to the outboard landing
lights, until the wire bundles and electrical connectors have been
replaced.
For all airplanes, a detailed inspection for any broken,
damaged, or missing fairleads, any damaged or missing grommets, and any
chafed or damaged wires or wire bundles in the four electrical junction
boxes of the main wheel well, and corrective actions if necessary.
For certain airplanes, replacement of certain wire bundles
for the landing lights and fuel shutoff valves with new, re-designed
wire bundles, and related investigative, other specified, and
corrective actions if necessary.
For certain airplanes, replacement of certain electrical
connectors and backshell clamps with new, improved electrical
connectors and backshell clamps.
Difference Between the Proposed AD and Service Bulletins
Although Boeing Service Bulletin 737-28-1241 and Boeing Alert
Service Bulletin 737-33A1140 specify prior or concurrent accomplishment
of Boeing Special Attention Service Bulletin 737-28-1196, this proposed
AD would not require that action. The accomplishment of Boeing Special
Attention Service Bulletin 737-28-1196 is already required by AD 2005-
10-11, amendment 39-14088 (70 FR 28419, May 18, 2005).
Costs of Compliance
We estimate that the actions specified in Boeing Alert Service
Bulletin 737-33A1140 would affect about 511 Model 737-300, -400, and -
500 series airplanes of U.S. registry. Operators may accomplish either
the deactivation or modification.
We estimate that the deactivation would take about 1 work-hour per
product to comply with this proposed AD. The average labor rate is $80
per work-hour. Based on these figures, we estimate the cost of the
deactivation to the U.S. operators to be $40,880, or $80 per product.
We estimate that the modification would take about 31 work-hours
per product to comply with this proposed AD. The average labor rate is
$80 per work-hour. Required parts for the modification would cost about
$573 per product. Based on these figures, we estimate the cost of
modification to the U.S. operators to be $1,560,083, or $3,053 per
product.
We estimate that the actions specified in Boeing Alert Service
Bulletin 737-28-1241 would affect up to 891 Model 737-100, -200, -200C,
-300, -400, and -500 series airplanes of U.S. registry. The following
table provides the estimated costs, at an average labor rate of $80 per
work-hour, for U.S. operators to comply with the actions specified in
that service bulletin.
Estimated Costs
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Number of U.S.-
Action Work hours Parts Cost per registered Fleet cost
airplane airplanes
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Part 1--Replacement of wire bundles... Up to 91....................... Up to $18,439.................. $25,719 511 $13,142,409
Part 2--Inspection of junction boxes.. 1.............................. 0.............................. 80 891 71,280
Part 3--Replacement of electrical 2.............................. 298............................ 458 400 183,200
connectors.
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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 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.
[[Page 62940]]
For the reasons discussed above, I certify this 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.
You can find our regulatory evaluation and the estimated costs of
compliance in the AD Docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, 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 AD:
Boeing: Docket No. FAA-2008-1116; Directorate Identifier 2007-NM-
231-AD.
Comments Due Date
(a) We must receive comments by December 8, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-100, -200, -200C, -300,
-400, and -500 series airplanes, certificated in any category; as
identified in Boeing Service Bulletin 737-28-1241, Revision 1, dated
August 31, 2007.
Unsafe Condition
(d) This AD results from reports of uncommanded engine shutdowns
and burned and damaged wire bundles associated with the outboard
landing lights and engine fuel shutoff valves. This AD also results
from reports of damaged and missing grommets and broken and damaged
fairleads in the electrical junction boxes of the main wheel well.
We are issuing this AD to prevent a hot short between the outboard
landing light and fuel shutoff valve circuits, which could result in
an uncommanded engine shutdown. We are also issuing this AD to
prevent corrosion of the electrical connectors of the wing rear
spars, which could result in short circuits and consequent incorrect
functioning of airplane systems needed for safe flight and landing.
Compliance
(e) Comply with this AD within the compliance times specified,
unless already done.
Deactivation or Modification of the Outboard Landing Lights
(f) For Model 737-300, -400, and -500 series airplanes
identified in Boeing Alert Service Bulletin 737-33A1140, dated May
22, 2006 (``the alert service bulletin''): Within 180 days after the
effective date of this AD, accomplish the actions specified in
either paragraph (f)(1) or (f)(2) of this AD. Accomplishing the
applicable actions required by paragraph (g) of this AD terminates
the requirements of this paragraph.
(1) Deactivate the outboard landing lights, by accomplishing all
of the actions specified in Part 1 of the Accomplishment
Instructions of the alert service bulletin.
Note 1: The Master Minimum Equipment List (MMEL) prohibits
dispatching an airplane for night operations with deactivated
outboard landing lights in the event that either of the inboard
landing lights fail. Operators should note that, if the outboard
landing lights are deactivated in accordance with Part 1 of the
service bulletin, there is no MMEL relief allowing for this
configuration for night operations should any inboard landing light
fail.
(2) Modify the wiring to the outboard landing lights, by
accomplishing all of the actions specified in Part 2 of the
Accomplishment Instructions of the alert service bulletin.
Inspection and Replacements
(g) For all airplanes: Within 60 months after the effective date
of this AD, do the applicable actions specified in paragraphs
(g)(1), (g)(2), and (g)(3) of this AD, by accomplishing all of the
applicable actions specified in the Accomplishment Instructions of
Boeing Service Bulletin 737-28-1241, Revision 1, dated August 31,
2007. For Model 737-300, -400, and -500 series airplanes identified
in Boeing Alert Service Bulletin 737-33A1140, dated May 22, 2006,
accomplishing the applicable actions required by this paragraph
terminates the requirements of paragraph (f) of this AD.
(1) Replace the wire bundles for the landing lights and fuel
shutoff valves with new, re-designed wire bundles, and do the
related investigative, other specified, and corrective actions, as
applicable. The related investigative, other specified, and
corrective actions must be done before further flight after the
replacement.
(2) Do a detailed inspection for any broken, damaged, or missing
fairleads, any damaged or missing grommets, and any chafed or
damaged wires or wire bundles in the four electrical junction boxes
of the main wheel well, and do the applicable corrective actions.
The corrective actions must be done before further flight after the
inspection.
(3) Replace the electrical connectors and backshell clamps with
new, improved electrical connectors and backshell clamps, as
applicable.
Credit for Actions Done According to Previous Issue of Service Bulletin
(h) For airplanes identified as Groups 1 and 2 in Boeing Service
Bulletin 737-28-1241, Revision 1, dated August 31, 2007: Actions
done before the effective date of this AD in accordance with Boeing
Service Bulletin 737-28-1241, dated April 7, 2006, are acceptable
for compliance with the requirements of paragraph (g) of this AD.
(i) For all airplanes: Actions done before the effective date of
this AD in accordance with Part 2 of the Accomplishment Instructions
of Boeing Service Bulletin 737-28-1241, dated April 7, 2006, are
acceptable for compliance with the requirements of paragraph (g)(2)
of this AD.
Alternative Methods of Compliance (AMOCs)
(j)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, ATTN: Stephen Oshiro, Aerospace Engineer, Systems and Equipment
Branch, ANM-130S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton,
Washington 98057-3356; telephone (425) 917-6480; fax (425) 917-6590;
has the authority to approve AMOCs for this AD, if requested using
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.
Issued in Renton, Washington, on October 10, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-25048 Filed 10-21-08; 8:45 am]
BILLING CODE 4910-13-P