Definition
For IFR flights, the estimated time required from takeoff to arrive over the designated point, defined with reference to navigation aids, from which an instrument approach procedure is expected to begin, or, if no navigation aid is associated with the destination aerodrome, to arrive over the destination aerodrome. For VFR flights, the estimated time required from takeoff to arrive over the destination aerodrome.
Plain English
The pilot's best estimate of how long the entire flight will take, from the moment the wheels leave the ground to the moment the aircraft arrives over the destination (or, on an IFR flight, over the point where the approach begins).
Context Anchor
Seen on ICAO-format flight plans, especially when giving the planned time en route for a flight.
Derivation
Elapsed comes from the Latin elabi, meaning to slip or pass away — so 'elapsed time' is simply the time that has passed. 'Total estimated elapsed time' is the pilot's best guess of how much time will pass between takeoff and the defined arrival point.
Why Pilots Care
Allows ATC to anticipate arrival and triggers search-and-rescue protocols if the aircraft is significantly overdue.
Intuition Check
Do not read “time” here as the arrival clock time, such as 1430Z. It means the amount of time the flight is expected to take, such as 2 hours 15 minutes.
Example Sentence 1
On the ICAO flight plan, the pilot entered a total estimated elapsed time of 03:45 for the trip from Vancouver to Seattle and on to Portland.
Example Sentence 2
When the aircraft had not arrived thirty minutes past the total estimated elapsed time, ATC initiated overdue procedures.