Definition
The amount of usable fuel left on board an aircraft, expressed in hours and minutes of flying time at the present power setting and fuel flow, rather than in gallons or pounds. When reporting fuel remaining to ATC, pilots must state the actual flying time available, not the quantity of fuel.
Plain English
How much longer the aircraft can keep flying before the fuel runs out, given how fast it is currently burning fuel.
Context Anchor
Used during in-flight emergency communications when ATC asks for information such as souls on board and fuel remaining.
Why Pilots Care
Gives controllers the information needed to select suitable diversion airports and decide how urgently assistance is required.
Intuition Check
Do not treat this as just a fuel quantity. In this context, the important answer is time left to fly, usually stated as hours and minutes.
Example Sentence 1
When the controller asked for souls on board and fuel remaining, the pilot reported three persons and forty-five minutes.
Example Sentence 2
When asked for fuel remaining in time, the crew calculated based on their current power setting and headwind.