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SPECIAL AIRWORTHINESS INFORMATION BULLETIN NO. ACE-98-26
DATE April 23, 1998
AIRCRAFT CERTIFICATION SERVICE
800 INDEPENDENCE AVENUE, S.W.
WASHINGTON, DC 20591
PUBLISHED BY FAA, AFS-610,
P.O. BOX 26460,
OKLA. CITY, OK 73125
THIS IS ISSUED FOR INFORMATIONAL PURPOSES ONLY AND ANY RECOMMENDATION FOR CORRECTIVE ACTION IS NOT MANDATORY
The purpose of this Special Airworthiness Information Bulletin (SAIB) is to advise owners/operators of Augustair, Inc. (formerly Varga, Shinn, Morrisey, and Montanair) models 2150, 2150A and 2180 of a possible fuel mismanagement situation. This information is valuable to anyone who operates one of the above listed airplanes because of the possibility of fuel exhaustion especially when conducting maximum range/endurance flight. The SAIB is advisory in nature and not mandated by regulation.
This SAIB is prompted by reports of near total fuel exhaustion. This situation can occur when the airplane is flown after having been parked on a sloping ramp with one wing lower than the other and both fuel valves in the “on” position. The fuel will drain from the high wing to the low wing and may begin to siphon overboard when the fuel reaches the level of the vent outlet. Fuel can reach the level of the vent outlet during refueling if the tank is filled to a point above the vent outlet or the airplane is refueled when the fuel is cool and the fuel expands to the vent outlet as the fuel temperature rises with the outside temperature. Fuel siphoning, once begun, will continue until the fuel is drained below the level of the vent outlet, fuel pressure in the tank builds up too much to allow venting, the aircraft is moved to a level surface or at least one of the fuel valves is closed and a tank cap is loosened to relieve the pressure. Fuel loss may range from a fraction of a gallon to several gallons, depending on the circumstances. In addition to the loss of fuel, this condition presents a fire hazard.
The FAA is recommending, but not requiring the following:
a. Operators should ensure that a thorough preflight inspection is conducted prior to flight, including a physical verification of the fuel quantity. This alone will alleviate the possibility of operating the airplane with an insufficient/unknown fuel quantity.
b. Ensure that both fuel valves are in the correct position (off/on) prior to takeoff.
c. Ensure that both fuel valves are placed in the off position when the airplane is parked. This will prevent the initiation of fuel siphoning even on a sloping ramp. These measures are common sense but some operators are either unaware or are not utilizing them.
For Further Information Contact:
Jerry Robinette, Aerospace Engineer,
FAA, Atlanta Aircraft Certification Office,
1895 Phoenix Boulevard,
One Crown Center, Suite 450,
Atlanta, Georgia 30349;
telephone: (770) 703-6096;
facsimile: (770) 703-6097.