[Federal Register: January 2, 2008 (Volume 73, Number 1)]
[Proposed Rules]
[Page 84-87]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02ja08-20]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0389; Directorate Identifier 2007-NM-222-AD]
RIN 2120-AA64
Airworthiness Directives; Various Transport Category Airplanes
Equipped With Auxiliary Fuel Tanks Installed in Accordance With Certain
Supplemental Type Certificates
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 various transport category airplanes. This proposed AD would
require deactivation of Southeast Aero-Tek, Inc., auxiliary fuel tanks.
This proposed AD results from fuel system reviews conducted by the
manufacturer, which identified potential unsafe conditions for which
the manufacturer has not provided corrective actions. We are proposing
this AD to prevent 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.
DATES: We must receive comments on this proposed AD by February 19,
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.
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: Robert Bosak, Aerospace Engineer,
Propulsion and Services Branch, ACE-118A, FAA, Atlanta Aircraft
Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite
460, Atlanta, Georgia 30349; telephone (770) 703-6094; fax (770) 703-
6097.
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-2007-0389;
Directorate Identifier 2007-NM-222-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) design
approval) holders to substantiate that their fuel tank systems can
prevent ignition sources in the fuel tanks. This requirement applies to
design approval 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
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combination with another 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 proposed 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.
Supplemental Type Certificates (STCs) for Southeast Aero-Tek, Inc.,
Auxiliary Fuel Tanks
The auxiliary fuel tank STCs on affected airplanes are a double-
walled cylindrical type design. The double-walled cylindrical tanks use
pneumatic air pressure to empty into the airplane's center wing tank.
All auxiliary tanks use some type of electrical fuel quantity
indication system (FQIS), flight deck control and annunciation panels,
float level switches, valves and venting systems, electrical wiring
connections in the dry bay area, and electrical bonding methods.
FAA's Findings
During the SFAR 88 safety assessment, it was determined that the
Southeast Aero-Tek, Inc., FQIS and float level switch did not meet
intrinsically safe electrical energy levels as described in the
guidelines of Advisory Circular (AC) 25.981-1B, ``Fuel Tank Ignition
Source Prevention Guidelines.'' Southeast Aero-Tek, Inc., identified
potential ignition sources resulting from a combination of single and
latent failures for the Southeast Aero-Tek, Inc., fuel tank subsystems.
To prevent high electrical energy levels from the FQIS and float level
switch from entering the auxiliary fuel tank, we have determined that
the appropriate solution for continued use is a combination of actions.
First, installing a transient suppression device (TSD) on FQIS and
float level switches would be needed. In order to maximize wire
separation, the TSD must be installed as close as possible to the
points where the FQIS and float level switch wires exit the TSD and
enter the auxiliary tank. Other actions might include replacing high-
energy FQISs, and float level switches that are impractical for TSD
application with intrinsically safe FQISs providing wire separation,
conducting a one-time inspection and/or replacing aging float level
switch conduit assemblies, periodically inspecting the external dry bay
system components and wires, and testing the integrity of bonding
resistances.
Southeast Aero-Tek, Inc., has not fully provided the service
information required under SFAR 88 that would correct these conditions;
therefore, we must mandate the deactivation of all Southeast Aero-Tek,
Inc., auxiliary fuel tanks.
If operators do not wish to deactivate their auxiliary fuel tanks,
we will consider requests for alternative methods of compliance
(AMOCs). The most likely requests would be to allow continued use of
the tanks by showing compliance with SFAR 88. This would involve
obtaining STCs to modify the auxiliary fuel tank systems and developing
maintenance procedures to address the safety issues identified above.
Once an operator has deactivated a tank as proposed by this NPRM,
the operator might wish to remove the tank. This would require a
separate design approval, if an approved tank removal procedure does
not exist.
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 products
of this same type design. For this reason, we are proposing this AD,
which would require deactivation to prevent usage of auxiliary fuel
tanks.
Explanation of Compliance Time
In most ADs, we adopt a compliance time allowing a specified amount
of time after the AD's effective date. In this case, however, the FAA
has already issued regulations that require operators to revise their
maintenance/inspection programs to address fuel tank safety issues. The
compliance date for these regulations is December 16, 2008. To provide
for coordinated implementation of these regulations and this proposed
AD, we are using this same compliance date in this proposed AD.
Costs of Compliance
The following table provides the estimated costs for the 37 U.S.-
registered airplanes to comply with this proposed AD. Based on these
figures, the estimated costs for U.S. operators could be as high as
$239,760 to prepare and report the deactivation procedures, and
$133,200 to deactivate tanks.
Estimated Costs
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Average labor
Action Work hours rate per hour Parts Individual cost
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Report.......................... 1 $80 None................ $80, per STC.
Preparation of tank deactivation 80 80 None................ 6,400, per STC.
procedure.
Physical tank deactivation...... 30 80 1,200............... 3,600, per airplane.
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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:
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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):
Various Transport Category Airplanes: Docket No. FAA-2007-0389;
Directorate Identifier 2007-NM-222-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by February
19, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to airplanes, certificated in any category,
and equipped with auxiliary fuel tanks installed in accordance with
specified supplemental type certificates (STCs), as identified in
Table 1 of this AD.
Table 1.--Affected Airplanes
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Airplanes Auxiliary tank STC(s)
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Boeing Model 727-100 series airplanes.. ST01587AT.
Boeing Model 727-200 and -200F series SA2033NM, SA1474SO
airplanes.
McDonnell Douglas Model DC-9-14 SA1334NM
airplanes.
McDonnell Douglas Model DC-9-32, DC-9- SA1710SO and SA1358NM
32 (VC-9C), DC-9-32F, DC-9-33F, and DC-
9-32F (C-9A, C-9B) airplanes.
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Unsafe Condition
(d) This AD results from fuel system reviews conducted by the
manufacturer, which identified potential unsafe conditions for which
the manufacturer has not provided corrective actions. We are issuing
this AD to prevent 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.
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.
Report
(f) Within 45 days after the effective date of this AD, submit a
report to the Manager, Atlanta Aircraft Certification Office (ACO),
FAA. The report must include the information listed in paragraphs
(f)(1) and (f)(2) of this AD. Under the provisions of the Paperwork
Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and
Budget (OMB) has approved the information collection requirements
contained in this AD, and assigned OMB Control Number 2120-0056.
(1) The airplane registration and auxiliary tank STC number
installed.
(2) The usage frequency in terms of total number of flights per
year and total number of flights per year for which the auxiliary
tank is used.
Prevent Usage of Auxiliary Fuel Tanks
(g) On or before December 16, 2008, deactivate the auxiliary
fuel tanks, in accordance with a deactivation procedure approved by
the Manager of the Atlanta ACO. Any auxiliary tank component that
remains on the airplane must be secured and must have no effect on
the continued operational safety and airworthiness of the airplane.
Deactivation may not result in the need for additional instructions
for continued airworthiness.
Note 1: Appendix A of this AD provides criteria that should be
included in the deactivation procedure. The proposed deactivation
procedures should be submitted to the Manager, Atlanta ACO as soon
as possible to ensure timely review and approval.
Note 2: For technical information, contact Randy Smith,
President, Southeast Aero-Tek, Inc., 675 Oleander Drive, Merritt
Island, Florida 32952; telephone (321) 453-7876; fax (321) 453-7872.
Alternative Methods of Compliance (AMOCs)
(h)(1) The Manager, Atlanta 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.
Appendix A--Deactivation Criteria
The auxiliary fuel tank deactivation procedure required by
paragraph (g) of this AD should address the following actions.
(1) Permanently drain auxiliary fuel tanks, and clear them of
fuel vapors to eliminate the possibility of out-gassing of fuel
vapors from the emptied auxiliary tank.
(2) Disconnect all electrical connections from the fuel quantity
indication system (FQIS), fuel pumps if applicable, float switches,
and all other electrical connections required for auxiliary tank
operation, and stow them at the auxiliary tank interface.
(3) Disconnect all pneumatic connections if applicable, cap them
at the pneumatic source, and secure them.
(4) Disconnect all fuel feed and fuel vent plumbing interfaces
with airplane original equipment manufacturer (OEM) tanks, cap them
at the airplane tank side, and secure them in accordance with a
method approved by the FAA; one approved method is specified in AC
25-8 Fuel Tank Flammability Minimization. In order to eliminate the
possibility of structural deformation during cabin decompression,
leave open and secure the disconnected auxiliary fuel tank vent
lines.
(5) Pull and collar all circuit breakers used to operate the
auxiliary tank.
(6) Revise the weight and balance document, if required, and
obtain FAA approval.
(7) Amend the applicable sections of the applicable airplane
flight manual (AFM) to indicate that the auxiliary fuel tank is
deactivated. Remove auxiliary fuel tank operating procedures to
ensure that only the OEM fuel system operational procedures are
contained in the AFM. Amend the Limitations Section of the AFM to
indicate that the AFM Supplement for the STC is not in effect. Place
a placard in the flight deck indicating that the auxiliary tank is
deactivated. The AFM revisions specified in
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this paragraph may be accomplished by inserting a copy of this AD
into the AFM.
(8) Amend the applicable sections of the applicable airplane
maintenance manual to remove auxiliary tank maintenance procedures.
(9) After the auxiliary fuel tank is deactivated, accomplish
procedures such as leak checks and pressure checks deemed necessary
before returning the airplane to service. These procedures must
include verification that the airplane FQIS and fuel distribution
systems have not been adversely affected.
(10) Include with the operator's proposed procedures any
relevant information or additional steps that are deemed necessary
by the operator to comply with the deactivation and return the
airplane to service.
Issued in Renton, Washington, on December 19, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-25482 Filed 12-31-07; 8:45 am]
BILLING CODE 4910-13-P