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Airworthiness Directives; Various Transport Category Airplanes Equipped With Auxiliary Fuel Tanks Installed in Accordance With Certain Supplemental Type Certificates

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Information about this document as published in the Federal Register.

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Federal Aviation Administration (FAA), DOT.


Final rule.


We are adopting a new airworthiness directive (AD) for various transport category airplanes. This AD requires deactivation of Southeast Aero-Tek, Inc., auxiliary fuel tanks. 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.


This AD is effective May 2, 2008.

Examining the AD Docket

You may examine the AD docket on the Internet at;​ 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 AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (telephone 800-647-5527) is the Document Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building, Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

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Robert Bosak, Aerospace Engineer, Propulsion and Services Branch, ACE-118A, FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 30349; telephone (770) 703-6094; fax (770) 703-6097.

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We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to various transport category airplanes equipped with auxiliary fuel tanks installed in accordance with certain supplemental type certificates (STCs). That NPRM was published in the Federal Register on January 2, 2008 (73 FR 84). That NPRM proposed to require deactivation of Southeast Aero-Tek, Inc., auxiliary fuel tanks.


We gave the public the opportunity to participate in developing this AD. We considered the comment received from the one commenter.

Request To Clarify Proposed Applicability

FedEx Express requests that we clarify the applicability statement in the NPRM to state that the AD does not apply to airplanes where auxiliary tanks were removed by an FAA-approved method. FedEx states that the unsafe condition does not exist on these airplanes.

We agree that the unsafe condition does not exist on the airplanes FedEx describes. We have included a statement in paragraph (c) of the final rule that excludes these airplanes.

Explanation of Change to Product Identification Line

We have changed the product identification line of the AD from “Various Transport Category Airplanes” to “Southeast Aero-Tek, Inc.” In ADs written against products with an STC, that statement is intended to identify the name of the STC holder.


We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

Costs of Compliance

The following table provides the estimated costs for the 37 U.S.-registered airplanes to comply with this 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

ActionWork hoursAverage labor rate per hourPartsIndividual cost
Report1$80None$80, per STC.
Preparation of tank deactivation procedure8080None$6,400, per STC.
Physical tank deactivation3080$1,200$3,600, per airplane.

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, Start Printed Page 16516Part 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

This AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Is not a “significant rule” under 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.

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List of Subjects in 14 CFR Part 39

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Adoption of the Amendment

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Accordingly, under the authority delegated to me by the Administrator, the FAA amends

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1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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2. The FAA amends § 39.13 by adding the following new AD:

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2008-07-09 Southeast Aero-Tek, Inc.: Amendment 39-15450. Docket No. FAA-2007-0389; Directorate Identifier 2007-NM-222-AD.

Effective Date

(a) This airworthiness directive (AD) is effective May 2, 2008.

Affected ADs

(b) None.


(c) This AD applies to airplanes, certificated in any category, equipped with auxiliary fuel tanks installed in accordance with specified supplemental type certificates (STCs), as identified in Table 1 of this AD. This AD does not apply to any airplane where an auxiliary fuel tank was installed in accordance with an STC identified in Table 1 of this AD and subsequently removed by an FAA-approved method.

Table 1.—Affected Airplanes

AirplanesAuxiliary tank STC(s)
Boeing Model 727-100 series airplanesST01587AT
Boeing Model 727-200 and -200F series airplanesSA2033NM, SA1474SO
McDonnell Douglas Model DC-9-14 airplanesSA1334NM
McDonnell Douglas Model DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-33F, and DC-9-32F (C-9A, C-9B) airplanesSA1710SO, SA1358NM

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.


(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.


(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, 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.

Material Incorporated by Reference

(i) None.

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 Advisory Circular 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.

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(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 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.

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Issued in Renton, Washington, on March 20, 2008.

Dionne Palermo,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. E8-6298 Filed 3-27-08; 8:45 am]