Soar to New Heights with the 2026 Commercial Pilot License (CPL) Practice Exam – Ready for Takeoff!

Switching to fan for 15 seconds in the air before turning off the cabin heater is crucial for ensuring that any residual heat and moisture are adequately dissipated. This process helps to prevent any potential buildup of carbon monoxide within the cabin, as well as reducing the risk of fogging on the windows, which can occur if the cabin air is too humid when the heater is turned off.

This practice is especially important in multi-engine aircraft like the Seminole, where maintaining a safe and comfortable cockpit environment is essential for both pilot and passenger safety. By running the cabin on fan mode for a brief period, you allow for better air circulation, which helps to clear out any stale air that may be trapped due to the heater's operation.

The other options do not effectively address the safety and performance considerations linked to the management of cabin heat. For instance, simply switching to off for two minutes on the ground may not allow for adequate ventilation or humidity control, and opening the cabin door briefly could disrupt the cabin environment without effectively addressing the moisture issue. Reducing engine RPMs to idle does not directly relate to the cabin heater operation and would not provide the necessary airflow needed to clear out the cabin effectively.