U.S. Department
of Transportation
Federal Aviation
Administration
Advisory
Circular
Date: 18 Jan 72 AC No. 20-29BSubject: USE OF AIRCRAFT FUEL ANTI-
ICING ADDITIVES
Initiated by : FS-140 Change:
1. PURPOSE. This circular provides information on the use of
anti-icing additives PFA-55MB and MIL-I-27686 as an
acceptable means of compliance with the Federal Aviation
Regulations that require assurance of continuous fuel flow
under conditions where ice may occur in turbine aircraft
fuel system.
2. CANCELLATION. AC 20-29A, effective June 19, 1967, is
cancelled.
3. REFERENCE REGULATIONS. Part 25, Section 25.997(b), of the
Federal Aviation Regulations.
4. BACKGROUND.
a. FAA - The Southern Region approved the use of a 0.10
percent concentration (by volume) of PFA-55MB in all
turbine aircraft fuels in December 1962. This approval
was based upon compatibility tests of the additive in
certificated aircraft and engines at a concentration of
0.15 percent of the fuel by volume and did not include
approval for the use of the additive in lieu of fuel
heaters. FAA may approve the 0.15 percent concentration
where compatibility with the aircraft and engine fuel
systems has been demonstrated (see Advisory Circular
AC 20-24A).
b. Air Force - The United States Air Force, after extensive
tests with PFA-55B in JP-4 fuel, concluded that the
additive satisfactorily prevents the formation of ice in
the fuel. Starting in April 1, 1962, this additive,
under its Military Specification No. MIL-I-27686A to D
was used in all JP-4 fuel produced in the United States.
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