[Federal Register: July 10, 2007 (Volume 72, Number 131)]
[Proposed Rules]
[Page 37484-37487]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr10jy07-19]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-28662; Directorate Identifier 2007-NM-014-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800
and -900 Series Airplanes; and Model 757-200, -200PF, -200CB, and -300
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 airplanes, identified above. This proposed AD would
require inspecting to determine if certain motor-operated shutoff valve
actuators for the fuel tanks are installed, and related investigative
and corrective actions if necessary. This proposed AD would also
require revising the Airworthiness Limitations (AWLs) section of the
Instructions for Continued Airworthiness to incorporate AWL No. 28-AWL-
21, No. 28-AWL-22, and No. 28-AWL-24 (for Model 737-600, -700, -700C, -
800 and -900 series airplanes), and No. 28-AWL-23, No. 28-AWL-24, and
No. 28-AWL-25 (for Model 757-200, -200PF, -200CB, and -300). This
proposed AD results from a design review of the fuel tank systems. We
are proposing this AD to prevent electrical energy from lightning, hot
shorts, or fault current from entering the fuel tank through the
actuator shaft, which could result in fuel tank explosions and
consequent loss of the airplane.
DATES: We must receive comments on this proposed AD by August 24, 2007.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD.
DOT Docket Web site: Go to http://dms.dot.gov and follow
the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to http://www.regulations.gov
and follow the instructions for sending your
comments electronically.
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.
Fax: (202) 493-2251.
Hand Delivery: Room W12-140 on the ground floor of the
West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207, for the service information identified in this
proposed AD.
FOR FURTHER INFORMATION CONTACT: Judy Coyle, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6497; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to submit any relevant written data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
28662; Directorate Identifier 2007-NM-014-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the proposed AD. We will
consider all comments received by the closing date and may amend the
proposed AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov
, including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA
personnel concerning this proposed AD. Using the search function of
that Web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit http://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at http://dms.dot.gov
, or in person at the Docket Operations office
[[Page 37485]]
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The Docket Operations office (telephone (800) 647-5527) is
located on the ground floor of the West Building at the street address
stated in the ADDRESSES section. Comments will be available in the AD
docket shortly after the Docket Management System receives them.
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 for ignition sources inside fuel
tanks caused by latent failures, alterations, repairs, or maintenance
actions, which, in combination with flammable fuel vapors, could result
in fuel tank explosions and consequent loss of the airplane.
Boeing has found that, under specific conditions, it was possible
for electrical current to flow through certain motor operated shutoff
valve actuators in the fuel tank. Boeing has developed a new valve
actuator to replace those actuators. A motor-operated shutoff valve
actuator that does not have sufficient protection against electrical
energy from lightning, hot shorts, and fault current, could allow
electrical energy to enter the fuel tank through the actuator drive
shaft, which could result in fuel tank explosions and consequent loss
of the airplane.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletins 737-28A1207, dated
February 15, 2007, and 757-28A0088, dated January 25, 2007. Boeing
Alert Service Bulletin 757-28A0088 describes procedures for inspecting
to determine the part number (P/N) of motor-operated valve (MOV)
actuators for the fuel tanks; Boeing Alert Service Bulletin 737-28A1207
also specifies removing MOV actuators having a certain P/N. The service
bulletins specify that no more work is necessary if the P/N is
acceptable.
For Boeing Model 737-600, -700, -700C, -800 and -900 series
airplanes, the affected MOVs are at 3 locations: The left engine fuel
shutoff (spar) valve, the right engine fuel shutoff (spar) valve, and
the fuel crossfeed valve. For Boeing Model 757-200, -200PF, -200CB, and
-300 series airplanes, the affected MOVs are at 6 locations for
airplanes in the single crossfeed configuration, or at 7 locations for
airplanes in the dual crossfeed configuration.
If the P/N is not acceptable, the service bulletins specify related
investigative and corrective actions as follows:
For all airplanes: Reworking the index plate; reworking the adapter
plate if necessary; installing the adapter/shaft plate with sealant;
installing the index plate with sealant; installing a new MOV actuator
on the index plate with sealant; installing bonding jumpers with
sealant. For Boeing Model 737-600, -700, -700C, -800 and -900 series
airplanes the actions also include installing shield ground terminals
using sealed fay surface bonding for the main tank fuel quantity
indicating system (FQIS). All of these actions include steps that
specify measuring the electrical bonding resistance between various
components and reworking the bonding if necessary.
We have also reviewed Subsection F, ``AIRWORTHINESS LIMITATIONS--
FUEL SYSTEM AWLs,'' of Boeing 737-600/700/700C/700IGW/800/900
Maintenance Planning Data (MPD) Document D626A001-CMR, Section 9,
Revision May 2006; and Subsection G, ``AIRWORTHINESS LIMITATIONS--FUEL
SYSTEM AWLs,'' of Boeing 757 MPD Document D622N001, Section 9, Revision
October 2006 (hereafter referred to as Revisions May 2006 and October
2006 of the MPDs). These sections of the MPDs describe the critical
design configuration control limitations (CDCCL) and inspections
applicable to the MOV installation. CDCCLs are limitation requirements
to preserve a critical ignition source prevention feature of the fuel
tank system design that is necessary to prevent the occurrence of an
unsafe condition. The purpose of a CDCCL is to provide instruction to
retain the critical ignition source prevention feature during
configuration change that may be caused by alterations, repairs, or
maintenance actions. A CDCCL is not a periodic inspection.
Subsection F of Revision May 2006 of the Boeing 737-600/700/700C/
700IGW/800/900 MPD adds new fuel system AWLs 28-AWL-21 (lightning and
fault current protection--MOV actuator), No. 28-AWL-22 (repair of the
MOV actuator), and 28-AWL-24 (lightning and fault current protection--
MOV actuator).
Subsection G of Revision October 2006 of the Boeing 757 MPD adds
new fuel system AWLs No. 28-AWL-23 (lightning and fault current
protection--MOV actuator), No. 28-AWL-24 (repair of the MOV actuator),
and No. 28-AWL-25 (lightning and fault current protection--MOV
actuator).
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 the following actions:
Inspecting to determine if certain motor-operated shutoff
valve actuators for the fuel tanks are installed, and
[[Page 37486]]
related investigative and corrective actions if necessary.
Revising the Airworthiness Limitations (AWLs) section of
the Instructions for Continued Airworthiness to incorporate AWL No. 28-
AWL-21, No. 28-AWL-22, and No. 28-AWL-24 (for 737-600, -700, -700C, -
800 and -900 series airplanes).
Revising the Airworthiness Limitations (AWLs) section of
the Instructions for Continued Airworthiness to incorporate AWL No. 28-
AWL-23, No. 28-AWL-24, and No. 28-AWL-25 (for Model 757-200, -200PF, -
200CB, and -300).
This proposed AD would also allow accomplishing the revision to the
AWLs section of the Instructions for Continued Airworthiness in
accordance with later revisions of the MPD as an acceptable method of
compliance if they are approved by the Manager, Seattle Aircraft
Certification Office, FAA.
Costs of Compliance
There are about 2,916 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 1,406 airplanes of
U.S. registry. The average labor rate is $80 per work hour.
Estimated Costs
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Number of U.S.-
Action Work hours Cost per registered Fleet cost
airplane airplanes
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Inspection for MOV actuators.................... 1 $80 1,406 $112,480
AWL revisions................................... 3 240 1,406 337,440
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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-2007-28662; Directorate Identifier 2007-NM-
014-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by August
24, 2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-600, -700, -700C, -800
and -900 series airplanes; and Boeing Model 757-200, -200PF, -200CB,
and -300 series airplanes, certificated in any category; as
identified in Boeing Alert Service Bulletins 737-28A1207, dated
February 15, 2007, and 757-28A0088, dated January 25, 2007.
Note 1: This AD requires revisions to certain operator
maintenance documents to include new inspections and maintenance
actions. Compliance with these limitations is required by 14 CFR
43.16 and 91.403(c). For airplanes that have been previously
modified, altered, or repaired in the areas addressed by these
limitations, the operator may not be able to accomplish the actions
described in the revisions. In this situation, to comply with 14 CFR
43.16 and 91.403(c), the operator must request approval for revision
to the airworthiness limitations (AWLs) in the Boeing 737-600/700/
700C/700IGW/800/900 Maintenance Planning Data (MPD) Document
D626A001-CMR and the Boeing 757 MPD Document D622N001-9, as
applicable, according to paragraph (h) of this AD.
Unsafe Condition
(d) This AD results from a design review of the fuel tank
systems. We are issuing this AD to prevent electrical energy from
lightning, hot shorts, or fault current from entering the fuel tank
through the actuator shaft, which could result in fuel tank
explosions and consequent loss 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.
Service Bulletin Reference
(f) The term ``service bulletin,'' as used in this AD, means the
Accomplishment Instructions of the following service bulletins, as
applicable:
(1) For Model 737-600, -700, -700C, -800 and -900 series
airplanes: Boeing Alert Service Bulletin 737-28A1207, dated February
15, 2007; and
(2) For Model 757-200, -200PF, -200CB, and -300 series
airplanes: Boeing Alert Service Bulletin 757-28A0088, dated January
25, 2007.
[[Page 37487]]
Inspection and Related Investigative/Corrective Actions
(g) Within 60 months after the effective date of this AD:
Inspect the applicable motor-operated valves (MOVs) to determine
whether an MOV with the affected part number (P/N) identified in the
Accomplishment Instructions of the applicable service bulletin is
installed. A review of airplane maintenance records is acceptable in
lieu of this inspection if the P/N of the part can be conclusively
determined from that review. Do all applicable related investigative
and corrective actions before further flight. Do all actions in
accordance with the Accomplishment Instructions of the applicable
service bulletin.
Revision of AWLs Section
(h) Concurrently with the actions in paragraph (g) of this AD:
Revise the AWLs section of the Instructions for Continued
Airworthiness by incorporating the information in paragraphs (h)(1)
and (h)(2) of this AD, as applicable. Accomplishing the revision in
accordance with a later revision of the MPD is an acceptable method
of compliance if the revision is approved by the Manager, Seattle
Aircraft Certification Office (ACO), FAA.
(1) Section F., ``AIRWORTHINESS LIMITATIONS--FUEL SYSTEM AWLs,''
of Boeing 737-600/700/700C/700IGW/800/900 Maintenance Planning Data
(MPD) Document D626A001-CMR, Section 9, Revision May 2006, into the
MPD to incorporate AWL No. 28-AWL-21, No. 28-AWL-22, and No. 28-AWL-
24.
(2) Section G., ``AIRWORTHINESS LIMITATIONS--FUEL SYSTEM AWLs,''
of Boeing 757 MPD Document D622N001, Section 9, Revision October
2006, into the MPD to incorporate AWL No. 28-AWL-23, No. 28-AWL-24,
and No. 28-AWL-25.
Alternative Methods of Compliance (AMOCs)
(i)(1) The Manager, Seattle 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.
Issued in Renton, Washington, on June 26, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-13366 Filed 7-9-07; 8:45 am]
BILLING CODE 4910-13-P