Takeoff is prohibited with engine fuel temperature indications below?

• A. 5°C
• B. 0°C
• C. -5°C
• D. 10°C

Answer: (A)

Fuel temperature matters because water in the fuel can freeze as the temperature drops, and ice in the fuel lines, filters, or metering components can block fuel flow just when the engine needs maximum fuel during takeoff. To ensure reliable fuel delivery, a safety margin is set: takeoff is prohibited if the engine fuel temperature indications are below five degrees Celsius. This threshold protects against icing risks and keeps engine operation safe during the high-demand takeoff phase. Warmer fuel (above five degrees) is unlikely to have ice formation, so takeoff is allowed, whereas temperatures at freezing or below (such as 0°C or -5°C) fall below the mandated limit. Fifty is chosen specifically to provide that safe buffer while allowing normal operations up to the limit.