Definition
An aircraft flown in close proximity to another aircraft, normally to observe its performance during training, testing, or evaluation. The chase pilot watches the other aircraft from outside, providing a second set of eyes for safety, monitoring configuration, and reporting observations the pilot of the observed aircraft cannot see for themselves.
Plain English
A second airplane that flies alongside another aircraft to watch it from the outside — usually during a test flight, training exercise, or unusual operation — so someone can see what the pilot inside cannot.
Context Anchor
Seen in flight test, special operations, demonstration flights, and any planned flight where one aircraft is assigned to observe another in the air.
Derivation
Chase comes from the Old French chacier, meaning to pursue or follow. In aviation, the chase aircraft follows the subject aircraft to observe it — not to catch it.
Why Pilots Care
Provides visual confirmation of aircraft behavior and an immediate safety backup during high-risk test flights.
Intuition Check
Do not read “chase” as an unplanned pursuit. A chase aircraft is a planned support aircraft flying nearby for observation or assistance.
Example Sentence 1
A chase aircraft accompanied the experimental jet on its first flight to monitor the landing gear and report any visible anomalies.
Example Sentence 2
After the formation breakup, the chase aircraft remained airborne to confirm all aircraft had landed safely.