What are the fuel temperature limitations?

• A. -50 C to 60 C
• B. -37 C to 57 C
• C. -40 C to 50 C
• D. -20 C to 70 C

Answer: (B)

Fuel temperature limits define the safe operating window for fuel in the aircraft’s systems, ensuring the fuel remains pumpable and the system components stay within tested conditions. If fuel is too cold, it can become too viscous and hinder proper fuel flow, potentially stressing pumps and filters. If fuel gets too hot, higher vapor pressure and changes in fuel characteristics can affect metering, cause vapor lock risks, and push components beyond their rated tolerances. The aircraft’s published limit is -37 C to 57 C, which keeps fuel within a reliable range for flow, pressure, and sensing accuracy. Other options either extend beyond what the system is designed to tolerate (risking damage or unreliable operation) or fall short of the necessary bounds to maintain safe handling and performance.