[Federal Register Volume 73, Number 201 (Thursday, October 16, 2008)]
[Proposed Rules]
[Pages 61369-61372]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-24542]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-1098; Directorate Identifier 2008-NM-108-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP
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 747-100, 747-100B, 747-100B SUD, 747-200B, 747-
200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. This
proposed AD would require adding two new indicator lights on the P10
panel to inform the captain and first officer of a low pressure
condition in the left and right override/jettison pumps of the center
wing tanks. This proposed AD would also require replacing the left and
right override/jettison switches on the M154 fuel control module on the
P4 panel with improved switches and doing the associated wiring
changes. This proposed AD would also require a revision to the FAA-
approved maintenance program to incorporate airworthiness limitation
No. 28-AWL-22. This proposed AD results from fuel system reviews
conducted by the manufacturer. We are proposing this AD to prevent
uncommanded operation of the override/jettison pumps of the center wing
tanks, which could lead to an unwanted ignition source inside the
center wing tank. This condition, in combination with flammable fuel
vapors, could result in a center fuel tank explosion and consequent
loss of the airplane.
DATES: We must receive comments on this proposed AD by December 1,
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
[[Page 61370]]
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: Sulmo Mariano, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6501; 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-2008-1098;
Directorate Identifier 2008-NM-108-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
The FAA has examined the underlying safety issues involved in fuel
tank explosions on several large transport airplanes, including the
adequacy of existing regulations, the service history of airplanes
subject to those regulations, and existing maintenance practices for
fuel tank systems. As a result of those findings, we issued a
regulation titled ``Transport Airplane Fuel Tank System Design Review,
Flammability Reduction and Maintenance and Inspection Requirements''
(66 FR 23086, May 7, 2001). In addition to new airworthiness standards
for transport airplanes and new maintenance requirements, this rule
included Special Federal Aviation Regulation No. 88 (``SFAR 88,''
Amendment 21-78, and subsequent Amendments 21-82 and 21-83).
Among other actions, SFAR 88 requires certain type design (i.e.,
type certificate (TC) and supplemental type certificate (STC)) holders
to substantiate that their fuel tank systems can prevent ignition
sources in the fuel tanks. This requirement applies to type design
holders for large turbine-powered transport airplanes and for
subsequent modifications to those airplanes. It requires them to
perform design reviews and to develop design changes and maintenance
procedures if their designs do not meet the new fuel tank safety
standards. As explained in the preamble to the rule, we intended to
adopt airworthiness directives to mandate any changes found necessary
to address unsafe conditions identified as a result of these reviews.
In evaluating these design reviews, we have established four
criteria intended to define the unsafe conditions associated with fuel
tank systems that require corrective actions. The percentage of
operating time during which fuel tanks are exposed to flammable
conditions is one of these criteria. The other three criteria address
the failure types under evaluation: Single failures, single failures in
combination with a latent condition(s), and in-service failure
experience. For all four criteria, the evaluations included
consideration of previous actions taken that may mitigate the need for
further action.
We have determined that the actions identified in this AD are
necessary to reduce the potential of ignition sources inside fuel
tanks, which, in combination with flammable fuel vapors, could result
in fuel tank explosions and consequent loss of the airplane.
Currently, there are lights on the flight engineer's P4 panel to
provide pressure indication for the override/jettison pumps of the left
and right center wing tanks. These lights are illuminated to inform the
flight engineer that a low pressure or no fuel flow condition exists. A
pump uncommanded-on is an event that may result in the pump running dry
and illumination of the associated low pressure light. This event
requires the flight engineer to manually pull the pump circuit breaker
to shut off the pump. To limit the potential of the pump running dry
for an extended period of time, Boeing has found that two new indicator
lights must be added to the forward panel on the flight deck to inform
the captain and first officer of a low pressure condition in the
override/jettison pumps. The P4 panel must also be modified to provide
the flight engineer with switches to shut off the override/jettison
pumps and the new indicator lights.
Uncommanded operation of the override/jettison pumps of the center
wing tanks could lead to an unwanted ignition source inside the center
wing tank. These conditions, if not corrected, in combination with
flammable fuel vapors, could result in a center fuel tank explosion and
consequent loss of the airplane.
Other Related Rulemaking
On April 28, 2008, we issued AD 2008-10-07, amendment 39-15513 (73
FR 25977, May 8, 2008), applicable to certain Boeing Model 747-100,
747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR,
and 747SP series airplanes. That AD requires revising the FAA-approved
maintenance program by incorporating new airworthiness limitations
(AWLs) for fuel tank systems to satisfy SFAR 88 requirements. That AD
also requires the initial accomplishment of certain repetitive AWL
inspections to phase in those inspections, and repair if necessary. As
an optional action, that AD also allows incorporating AWL No. 28-AWL-22
into the FAA-approved maintenance program. Incorporating AWL No. 28-
AWL-22 into the FAA-approved maintenance program in accordance with
paragraph (g) of AD 2008-10-07 would terminate the action specified in
paragraph (g) of this proposed AD.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 747-28A2288, dated
March 20, 2008. The service bulletin describes procedures for adding
two indicator lights on the P10 panel to inform the captain and first
officer of a low pressure condition in the left and right override/
jettison pumps of the center wing tanks. The service bulletin also
describes procedures for replacing the left and right override/jettison
switches on certain M154 fuel control modules on the P4 panel with
improved switches, and doing the associated wiring changes.
For airplanes equipped with certain other M154 fuel control
modules, Boeing Alert Service Bulletin 747-28A2288 refers to the BAE
Systems service bulletins in the following table as additional sources
of service information for replacing the switches and doing the
associated wiring changes, as applicable:
[[Page 61371]]
Additional Sources of Service Information
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Service Bulletin Date
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BAE Systems Service Bulletin February 16, 2006.
65B46124-28-01.
BAE Systems Service Bulletin March 28, 2007.
65B46124-28-02.
BAE Systems Service Bulletin March 28, 2007.
65B46124-28-03.
BAE Systems Service Bulletin February 16, 2006.
65B46214-28-01.
BAE Systems Service Bulletin March 28, 2007.
65B46214-28-02.
BAE Systems Service Bulletin March 28, 2007.
65B46214-28-03.
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We have also reviewed the Boeing 747-100/200/300/SP Airworthiness
Limitations (AWLs) and Certification Maintenance Requirements (CMRs),
D6-13747-CMR, Revision March 2008 (hereafter referred to as ``Document
D6-13747-CMR''). (For the purposes of Document D6-13747-CMR, the Model
747SR series airplane is basically a Model 747-100 series airplane with
certain modifications to improve fatigue life.) Section D of Document
D6-13747-CMR describes AWLs for fuel tank systems. Section D of
Document D6-13747-CMR includes fuel system AWL No. 28-AWL-22, which is
a repetitive inspection (test) to verify continued functionality of the
low pressure indicator lights on the P10 panel for the override/
jettison pumps of the center wing tanks.
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 accomplishing the following
actions:
Adding two new indicator lights on the P10 panel to inform
the captain and first officer of a low pressure condition in the left
and right override/jettison pumps of the center wing tanks.
Replacing the left and right override/jettison switches on
the M154 fuel control module on the P4 panel with improved switches and
doing the associated wiring changes.
Revising the FAA-approved maintenance program to
incorporate AWL No. 28-AWL-22, which is a repetitive inspection to
verify continued functionality of the low pressure indicator lights on
the P10 panel for the override/jettison pumps of the center wing tanks.
Costs of Compliance
We estimate that this proposed AD would affect 185 airplanes of
U.S. registry. We also estimate that it would take up to 28 work-hours
per product to comply with this proposed AD. The average labor rate is
$80 per work-hour. Required parts would cost up to $2,668 per product.
Based on these figures, we estimate the cost of this proposed AD to the
U.S. operators up to $907,980, or $4,908 per product.
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.
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, 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-2008-1098; Directorate Identifier 2008-NM-
108-AD.
Comments Due Date
(a) We must receive comments by December 1, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series
airplanes, certificated in any category; as identified in Boeing
Alert Service Bulletin 747-28A2288, dated March 20, 2008.
Note 1: This AD requires revisions to certain operator
maintenance documents to include a new inspection. Compliance with
this inspection is required by 14 CFR 91.403(c). For airplanes that
have been previously modified, altered, or repaired in the areas
addressed by this inspection, the operator may not be able to
accomplish the inspections described in the revisions. In this
situation, to comply with 14 CFR 91.403(c), the operator must
request approval for an alternative method of compliance (AMOC)
according to paragraph (j) of this AD. The request should include a
description of changes to the required inspection that will ensure
the continued operational safety of the airplane.
Unsafe Condition
(d) This AD results from fuel system reviews conducted by the
manufacturer. We are issuing this AD to prevent uncommanded
operation of the override/jettison pumps of
[[Page 61372]]
the center wing tanks, which could lead to an unwanted ignition
source inside the center wing tank. This condition, in combination
with flammable fuel vapors, could result in a center fuel tank
explosion and consequent loss of the airplane.
Compliance
(e) Comply with this AD within the compliance times specified,
unless already done.
Installation of Indicator Lights and Replacement of Switches
(f) Within 36 months after the effective date of this AD: Add
two new indicator lights on the P10 panel to inform the captain and
first officer of a low pressure condition in the left and right
override/jettison pumps of the center wing tanks; and replace the
left and right override/jettison switches on the M154 fuel control
module on the P4 panel with improved switches and do the associated
wiring changes; by accomplishing all of the applicable actions
specified in the Accomplishment Instructions of Boeing Alert Service
Bulletin 747-28A2288, dated March 20, 2008.
Note 2: For airplanes equipped with certain M154 fuel control
modules, paragraph 2.C.2 of Boeing Alert Service Bulletin 747-
28A2288 refers to the BAE Systems service bulletins identified in
Table 1 of this AD, as applicable, as additional sources of service
information for replacing the switches.
Table 1--Additional Sources of Service Information
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Service Bulletin Date
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BAE Systems Service Bulletin February 16, 2006.
65B46124-28-01.
BAE Systems Service Bulletin March 28, 2007.
65B46124-28-02.
BAE Systems Service Bulletin March 28, 2007.
65B46124-28-03.
BAE Systems Service Bulletin February 16, 2006.
65B46214-28-01.
BAE Systems Service Bulletin March 28, 2007.
65B46214-28-02.
BAE Systems Service Bulletin March 28, 2007.
65B46214-28-03.
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Maintenance Program Revision
(g) Concurrently with accomplishing the actions required by
paragraph (f) of this AD, revise the FAA-approved maintenance
program by incorporating Airworthiness Limitation (AWL) No. 28-AWL-
22 of Section D of the Boeing 747-100/200/300/SP Airworthiness
Limitations (AWLs) and Certification Maintenance Requirements
(CMRs), D6-13747-CMR, Revision March 2008.
No Alternative Inspections or Inspection Intervals
(h) After accomplishing the action specified in paragraph (g) of
this AD, no alternative inspections or inspection intervals may be
used unless the inspections or inspection intervals are approved as
an AMOC in accordance with the procedures specified in paragraph (j)
of this AD.
Terminating Action for Maintenance Program Revision
(i) Incorporating AWL No. 28-AWL-22 into the FAA-approved
maintenance program in accordance with paragraph (g) of AD 2008-10-
07, amendment 39-15513, terminates the action required by paragraph
(g) of this AD.
Alternative Methods of Compliance (AMOCs)
(j)(1) The Manager, Seattle ACO, FAA, ATTN: Sulmo Mariano,
Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle ACO,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6501; fax (425) 917-659; 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 7, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-24542 Filed 10-15-08; 8:45 am]
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