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Proposed Advisory Circulars (AC) 25.981-1X, Fuel Tank Ignition Source Prevention Guidelines; and AC 25.981-2X, Fuel Tank Flammability Minimization

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Federal Aviation Administration, DOT.


Notice of proposed advisory circulars.


The Federal Aviation Administration invites public comment on draft advisory material that provides guidelines for demonstrating compliance with proposed certification requirements for preventing ignition sources within the fuel tanks of transport category airplanes, as well as minimizing the formation of flammable vapors in the fuel tanks of those airplanes.


Comments must be received on or before March 27, 2000.


Send all comments on the proposed advisory circulars to the Federal Aviation Administration, Attention: Mike Dostert, Propulsion/Mechanical Systems Branch, ANM-112, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Ave. SW., Renton, WA 98055-4056. Comments may also be submitted electronically to the following address:

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Mike Dostert at the above address, telephone (425) 227-2132; facsimile (425) 227-1320, or e-mail

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How Do I Obtain a Copy of the Proposed Advisory Circulars?

You may obtain an electronic copy of the advisory circulars identified in this notice at the following Internet address:​avr/​air/​airhome. htm. If you do not have access to the Internet, you may request a copy by contacting Domonique Adams, Program Management Branch, ANM-114, FAA Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, WA 98055-4056; telephone (425) 227-2111.

How Do I Submit Comments on the Advisory Circulars?

Interested persons are invited to comment on the proposed advisory material by submitting such written data, views, or arguments as they may desire. Comments must identify the title of the AC and be submitted in duplicate to the address specified above. The Transport Airplane Directorate will consider all comments received on or before the closing date for comments before issuing the final advisory material.


In Notice of Proposed Rulemaking 99-18, published in the Federal Register on October 29, 1999 (64 FR 58656), the FAA requested public comment on a proposal to require design approval holders of certain turbine-powered transport category airplanes to submit substantiation to the FAA that the design of the fuel tank system of previously certificated airplanes precludes the existence of ignition sources within the airplane fuel tanks. The proposed rule would also require the affected design approval holders to develop specific fuel tank system maintenance and inspection instructions for any items in the fuel tank system that re determined to require repetitive inspections or maintenance, to assure the safety of the fuel tank system. In addition, the proposed rule would require certain operators of those airplanes to incorporate FAA-approved fuel tank system maintenance and inspection instructions into their current maintenance or inspection program.

In addition to the amendments proposed in Notice 99-18, the FAA announced the development of advisory material to supplement the proposals. This notice announces the availability of that advisory material for public comment.

The first advisory circular, AC 25.981-1X, Fuel Tank Ignition Source Prevention Guidelines, provides Start Printed Page 5013guidance on how to substantiate that ignition sources will not be present in airplane fuel tank systems following failures or malfunctions of airplane components or systems. Also included is guidance for developing any limitations for the instructions for Continued Airworthiness that may be generated by the fuel tank system safety assessment identified in Notice 99-18.

The second advisory circular, AC 25.981-2X, Fuel Tank flammability Minimization, provides information and guidance concerning compliance with the standards proposed in Notice 99-18 pertaining to minimizing the formation of flammable vapors in the fuel tanks, or mitigation of any hazards if ignition does occur.

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Issued in Renton, WA, on January 14, 2000.

Vi L. Lipski,

Acting manager, Transport Airplane Directorate Aircraft Certification Service, ANM-100.

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[FR Doc. 00-2262 Filed 2-1-00; 8:45 am]