[Federal Register: October 7, 2008 (Volume 73, Number 195)]
[Proposed Rules]
[Page 58509-58512]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07oc08-24]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-1065; Directorate Identifier 2008-NM-126-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 727 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 727 airplanes. This proposed AD would require,
among other actions, installing new ground fault interrupter (GFI)
relays for the main fuel tanks and the auxiliary fuel tank pumps. This
proposed AD also would require revising the FAA-approved maintenance
program to incorporate new Airworthiness Limitations (AWLs) for the GFI
of the boost pumps and for the uncommanded on system for the auxiliary
fuel tank pumps. This proposed AD results from fuel system reviews
conducted by the manufacturer. We are proposing this AD to prevent an
electrical fault in the fuel pump system, which might cause a connector
or end cap to burn through and a subsequent fire or explosion inside
the fuel pump or wing spar area. We are also proposing this AD to
prevent uncommanded operation of the auxiliary fuel tank pumps, which
can cause them to run dry. This condition will increase pump
temperature and could supply an ignition source to fumes in the fuel
tank, which can result in a consequent fire or explosion.
DATES: We must receive comments on this proposed AD by November 21,
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: Binh Tran, Aerospace Engineer, Systems
and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6485; fax (425) 917-6590.
[[Page 58510]]
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-2008-1065;
Directorate Identifier 2008-NM-126-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.
We have determined that the fuel pump control system on certain
Model 727 airplanes must be changed by installing ground fault
interrupter (GFI) relays that will interrupt the electrical power to
the fuel pumps when a ground fault is detected. The GFI relays will
remove the 115VAC power from the fuel pumps before electrical arcing
can occur. An electrical fault in the fuel pump system, if not
corrected, might cause a connector or end cap to burn through and a
subsequent fire or explosion inside the fuel pump or wing spar area.
In addition, we have determined that electrical faults within the
fuel tank pump system on certain Model 727-100 and -200 series
airplanes can cause a pump to operate when the pump switch is in the
``OFF'' position (referred to as ``uncommanded on'' (UCO) pump
operation). Uncommanded operation of the auxiliary fuel tank pumps can
cause them to run dry, which will increase pump temperature and could
supply an ignition source to fumes in the fuel tank, and result in a
consequent fire or explosion.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 727-28A0128, dated
April 4, 2008. The service bulletin describes procedures for installing
new GFI relays for the main fuel tanks and the auxiliary fuel tank
pumps and doing other specified actions. The other specified actions
include installing new wires and modifying some existing wires to
support the installation of the new GFI relays.
We also have reviewed Boeing Alert Service Bulletin 727-28A0130,
dated April 30, 2008. The service bulletin describes procedures for:
Installing new ground blocks, track, switch mounting
bracket, relay mounting bracket, toggle switches, and relays, and
making changes to the wire bundles in the GFI relay panel in the
electronic equipment bay; and
Installing new circuit breakers and lights and making
changes to wire bundles on the third crewman's P6 and P4 panels in the
flight compartment.
For certain airplanes identified in Boeing Alert Service Bulletin
727-28A0128, the procedures specified in Boeing Alert Service Bulletin
727-28A0130 must be done concurrently with the procedures specified in
Boeing Alert Service Bulletin 727-28A0128.
In addition, we have reviewed ``Boeing 727-100/200 Airworthiness
Limitations (AWLs),'' D6-8766-AWL, Revision August 2007 (hereafter
referred to as ``Document D6-8766-AWL''). Document D6-8766-AWL
describes, among other actions, new AWLs for the GFI of the boost pumps
(i.e., 28-AWL-16) and for the Auxiliary Tanks Boost Pump Uncommanded On
System (i.e., 28-AWL-17).
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:
Installing new GFI relays for the main fuel tanks and the
auxiliary fuel tank pumps.
For certain airplanes, installing new ground blocks,
track, switch mounting bracket, relay mounting bracket, toggle
switches, and relays, and changing the wire bundles in the GFI relay
panel in the electronic equipment bay.
For certain airplanes, installing new circuit breakers and
lights and changing wire bundles on the third crewman's P6 and P4
panels in the flight compartment.
Revising the FAA-approved maintenance program to
incorporate AWL numbers 28-AWL-16 and 28-AWL-17, which would require
repetitive inspections of the GFI of the boost pumps and of the
uncommanded on system for the auxiliary fuel tank pumps, respectively.
Costs of Compliance
We estimate that this proposed AD would affect 199 airplanes of
U.S. registry. The following table provides the estimated costs for
U.S. operators to comply with this proposed AD.
[[Page 58511]]
Table--Estimated Costs
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Average Number of
labor rate U.S.-
Action Work hours per hour Parts Cost per product registered Fleet cost
(dollars) airplanes
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Installation of new GFI relays.... Between 202 and 416 $80 Between $30,619 and Between $46,779 and 199 Between $9,309,021
\1\. $59,785 \1\. $93,065 \1\. and $18,519,935 \1\.
Concurrent Requirements........... Between 68 and 209 80 Between $1,292 and Between $6,732 and 35 Between $235,620 and
\1\. $10,470 \1\. $27,190 \1\. $951,650 \1\.
Revision of FAA-approved 1.................... 80 None................. $80.................. 199 $15,920.
maintenance program.
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\1\ Depending on the airplane configuration.
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-2008-1065; Directorate Identifier 2008-NM-
126-AD.
Comments Due Date
(a) We must receive comments by November 21, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 727, 727C, 727-100, 727-
100C, 727-200, and 727-200F series airplanes, certificated in any
category; as identified in Boeing Alert Service Bulletin 727-
28A0128, dated April 4, 2008.
Note 1: This AD requires revisions to certain operator
maintenance documents to include new inspections. Compliance with
these inspections is required by 14 CFR 91.403(c). For airplanes
that have been previously modified, altered, or repaired in the
areas addressed by these inspections, 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 inspections 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 an electrical fault
in the fuel pump system, which might cause a connector or end cap to
burn through and a subsequent fire or explosion inside the fuel pump
or wing spar area. We are also issuing this AD to prevent
uncommanded operation of the auxiliary fuel tank pumps, which can
cause them to run dry. This condition will increase pump temperature
and could supply an ignition source to fumes in the fuel tank, which
can result in a consequent fire or explosion.
Compliance
(e) Comply with this AD within the compliance times specified,
unless already done.
Installation
(f) Within 60 months after the effective date of this AD,
install new ground fault interrupter (GFI) relays for the main fuel
tanks and the auxiliary fuel tank pumps and do all the other
specified actions by accomplishing all the applicable actions
specified in the Accomplishment Instructions of Boeing Alert Service
Bulletin 727-28A0128, dated April 4, 2008.
Concurrent Requirements
(g) For airplanes identified as Groups 5 through 18 inclusive,
in Boeing Alert Service Bulletin 727-28A0128, dated April 4, 2008:
Concurrently with the installation required by paragraph (f) of this
AD, do the actions specified in paragraphs (g)(1) and (g)(2) of this
AD in accordance with the Accomplishment Instructions of Boeing
Alert Service Bulletin 727-28A0130, dated April 30, 2008.
(1) Install new ground blocks, track, switch mounting bracket,
relay mounting bracket, toggle switches, and relays, and make
changes to the wire bundles in the GFI relay panel in the electronic
equipment bay.
(2) Install new circuit breakers and lights and make changes to
wire bundles on the third crewman's P6 and P4 panels in the flight
compartment.
Maintenance Program Revision
(h) Concurrently with accomplishing the installation required by
paragraph (f) of this AD, revise the FAA-approved maintenance
program by incorporating AWLs numbers 28-AWL-16 and 28-AWL-17 of
Section D of
[[Page 58512]]
the ``Boeing 727-100/200 Airworthiness Limitations (AWLs),'' D6-
8766-AWL, Revision August 2007 (hereafter referred to as ``Document
D6-8766-AWL.'')
No Alternative Inspection or Inspection Intervals
(i) After accomplishing the action required by paragraph (h) of
this AD, no alternative inspections or inspection intervals may be
used, unless the inspections or intervals are approved as an AMOC in
accordance with the procedures specified in paragraph (j) of this
AD.
Alternative Methods of Compliance (AMOCs)
(j)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, ATTN: Binh Tran, Aerospace Engineer, Systems and Equipment
Branch, ANM-130S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton,
Washington 98057-3356; telephone (425) 917-6485; 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 September 18, 2008.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-23668 Filed 10-6-08; 8:45 am]
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