Definition
The high-velocity stream of hot exhaust gases discharged rearward from a jet engine. Jet wake can produce hazardous conditions behind a running jet aircraft, including strong thrust forces, extreme heat, and ingestion or blast damage to people, equipment, and other aircraft positioned within its path.
Plain English
The blast of fast-moving hot air shooting out the back of a jet engine. Standing or taxiing behind a jet that is running can be dangerous because of the force, heat, and debris being blown backward.
Context Anchor
Encountered during takeoff, landing, taxi, and in-flight spacing behind jet aircraft.
Derivation
Wake' comes from the Old Norse 'vaka,' meaning a track or trail left behind something moving — originally the trail of disturbed water behind a ship. Applied to a jet, it describes the trail of disturbed, fast-moving air left behind the engine.
Why Pilots Care
Jet wake can produce strong rolling forces capable of upsetting or damaging a following aircraft, especially during takeoff and landing.
Analogy
It is like the rough water behind a fast boat, except the disturbed trail is in the air and usually cannot be seen.
Intuition Check
Do not think of jet wake as only smoke or hot exhaust. The main hazard is often invisible disturbed air behind the jet.
Example Sentence 1
The ground crew waited until the airliner had taxied well clear before walking behind it, knowing the jet wake could easily knock a person down.
Example Sentence 2
On final approach the pilot kept extra spacing behind the heavy jet to stay clear of its wake.