CFI Instrument Practical Test Standards, FAA-S-8081-9B, June 2001

II. Technical Subject Areas

A. Aircraft Flight Instruments and Navigation Equipment

3. Anti-ice/deicing and weather detection equipment and their operating characteristics
d. Fuel system
1) Fuel system ice results from presence of dissolved or undissolved (e.g., entrained) water in the fuel system
2) Water suspended in fuel may freeze and form ice crystals big enough to block fuel screens, strainers or filters, or cause carburetor metering component icing
3) Use of anti-icing fuel additives has been approved for some piston engine aircraft to prevent fuel system icing
4) Cessna TR-182
a) Proper preflight draining eliminates any free water accumulations from the tank sumps
b) Small amounts of water in solution will normally be consumed unnoticed
c) Anti-ice fuel additives
i) Generally not needed
ii) Permissable only when operating under the combined effects of
• Use of certain fuels
• High humidity on the ground
• Flight at high altitude and low temperature
iii) Under above conditions, may add either
• Isopropyl alcohol
  • MIL-F-5566 or
  • Federal Specification TT-I-735a compliant
  • 1% by volume
• Ethylene glycol monomethyl ether (EGME)
  • MIL-I-27686 compliant or
  • Phillips PFA-55MB
  • Not to exceed 0.15% by volume

References:
Instrument Flying Handbook, FAA-H-8083-15, 1999
The Instrument Flight Manual, Sixth Edition William K. Kershner, 2002
AC20-113 Pilot Precautions and Procedures to be Taken in Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems
AC91-51A Effect of Icing on Aircraft Control and Airplane Deice and Anti-Ice Systems
AC91-74 Pilot Guide: Flight in Icing Conditions

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