Fuel icing in cold weather

Cold weather hazard:

• All aviation fuel absorbs moisture from air.
• Cooling fuel: suspended water drops out of solution. Warming fuel: absorbs more.
• Fuel cooled to freezing point of water: suspended particles turn to ice crystals.
• Crystals build up in filters, line bends, fuel selectors, blocking the fuel line and stopping the engine.
• Manufacturer-approved anti-icing additives (e.g. EGME) inhibit ice-crystal formation. Use only as specified.
• Sump water can freeze and block fuel lines (PHAK ch.7).

Trap: suspended water turning to ice crystals blocks the fuel line and stops the engine.

Practice