Definition
A failure of a system, component, or piece of equipment to operate as intended. The item may produce no output at all, produce an incorrect output, or behave erratically.
Plain English
Something is not working the way it is supposed to. It might be completely broken, partly working, or giving wrong information.
Context Anchor
Pilots encounter this word in checklists, aircraft manuals, maintenance write-ups, and emergency or abnormal procedures.
Derivation
From the Latin 'mal-' meaning 'bad' or 'wrongly,' joined with 'function,' meaning 'to perform.' So a malfunction is something performing badly or wrongly — not necessarily failing completely.
Why Pilots Care
A malfunction can reduce aircraft capability or create an emergency, requiring the pilot to follow specific procedures to maintain safety.
Intuition Check
Do not assume a malfunction means something has completely failed. In aviation, a malfunction can also mean something is partly working, working irregularly, or showing values outside the normal range.
Example Sentence 1
The pilot declared an emergency after a malfunction in the landing gear extension system.
Example Sentence 2
The pilot followed the checklist after an electrical malfunction caused the radios to lose power.