Cooling air fans are used during which flight phases?

• A. Cruise phases only
• B. On the ground only
• C. During takeoff, landings, low level flights, on the ground operations
• D. During high altitude cruise only

Answer: (C)

Cooling air fans provide forced cooling when natural ram air flow isn’t enough to keep temperatures in check. This is most important during phases where the engine and equipment run at high power or where airspeed is limited, so the heat load is higher or there isn’t sufficient airflow over heat exchangers. That’s why they’re used during takeoff and climb (high power, limited ram air), during landing (transitional phase with variable speeds and power), during low level flight (slower speeds reduce ram air), and on the ground (no forward air movement). In high altitude cruise, ram air flow is usually more ample and the cooling demand is lower, so the fans aren’t typically needed.