The minimum ambient temperature to start a cold-soaked APU on the ground is which value?

The minimum ambient temperature to start a cold-soaked APU on the ground is which value?

• A. -40C
• B. -30C
• C. -50C
• D. -60C

Answer: (A)

When starting a cold-soaked APU on the ground, there is a lower limit on how cold the environment can be. This limit exists to protect the APU during start, particularly the lubrication and starter system, because oil viscosity increases and system components may not spin up reliably in extreme cold. The allowed minimum ambient temperature for a ground start is minus 40 degrees Celsius. That means you can start at -40 C or warmer, but attempting to start below that temperature is not permitted and would require preheating or an external power source to bring the APU up to a safe operating temperature.

When starting a cold-soaked APU on the ground, there is a lower limit on how cold the environment can be. This limit exists to protect the APU during start, particularly the lubrication and starter system, because oil viscosity increases and system components may not spin up reliably in extreme cold. The allowed minimum ambient temperature for a ground start is minus 40 degrees Celsius. That means you can start at -40 C or warmer, but attempting to start below that temperature is not permitted and would require preheating or an external power source to bring the APU up to a safe operating temperature.