Definition
A loss of useful engine output, electrical power, or both, that prevents normal operation of the aircraft or its systems. In flight, the term most commonly refers to either an engine power failure (partial or complete loss of thrust) or an electrical power failure (loss of the alternator, generator, or battery supply that feeds avionics and instruments).
Plain English
Something that should be producing power has stopped doing so. Either the engine isn't producing thrust the way it should, or the electrical system has stopped supplying current to the instruments and radios.
Context Anchor
In an inadvertent thunderstorm encounter, this term may appear when discussing serious hazards that can affect the aircraft’s engine or systems.
Why Pilots Care
Requires immediate action to maintain aircraft control and may force a diversion or emergency landing.
Grounding Statement
The key point is that the aircraft no longer has the normal power the pilot was counting on.
Intuition Check
Do not assume power failure always means everything shuts off at once. In aviation, it can also mean a serious partial loss of power that makes normal operation unsafe.
Example Sentence 1
After the lightning strike, the pilot suspected an electrical power failure when the primary flight display went dark.
Example Sentence 2
During thunderstorm avoidance training, the instructor simulated a power failure at low altitude to practice emergency procedures.