Under what conditions will you hear the action horn?

The action horn typically serves as an alert system that warns the pilot of specific aircraft configurations or conditions that require attention. In multi-engine aircraft, one of these critical conditions is related to manifold pressure (MP).

Hearing the action horn when the manifold pressure is below 14 inches is significant because it indicates a potential issue with engine performance or power settings that could impact the safety and operation of the aircraft. Manifold pressure is a critical measure in determining engine power output, and operating below certain thresholds can signify that the engine is not producing sufficient power for safe flight operations, particularly during critical phases like takeoff or climb.

The correct answer underscores the importance of maintaining an appropriate manifold pressure to ensure effective engine performance. Other options relate to specific flap positions and gear configurations; however, they do not directly correlate with the action horn's purpose, which is primarily centered around maintaining engine performance in multi-engine operations. The action horn's warning at 14 inches serves as an important reminder for pilots to manage their engine settings actively, ensuring that safe operational parameters are maintained. This aids in preventing situations that could jeopardize aircraft performance and safety.