What is a common indication of engine failure during flight?

Abnormal engine sounds or vibrations are indeed a common indication of engine failure during flight. When an aircraft's engine malfunctions, pilots might hear unusual noises such as banging, grinding, or sputtering, or they may feel increased vibrations. These auditory and sensory cues signal that something is not functioning normally within the engine, prompting pilots to take immediate action. Recognizing these signs is crucial for maintaining control and safety during the flight and can lead to prompt troubleshooting or emergency procedures.

In contrast, an increase in altitude, stable airspeed and descent rate, or sudden loss of cabin pressure do not typically indicate engine failure. An increase in altitude could reflect normal climbing behavior or a purposeful maneuver, while stable airspeed and descent rate might suggest controlled flight rather than an engine issue. A sudden loss of cabin pressure, although serious, is not directly connected to engine performance and can occur due to other factors, such as issues with the aircraft's fuselage or cabin systems.