
[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]

BILLING CODE 4910-13-P
