Ask a new pilot how long a flight was and they will tell you how long they were in the air. Ask their logbook and it will give a bigger number. The gap between those two answers is the difference between air time and flight time, and understanding it stops you from undercounting your own hours or being baffled by a rental bill.
This is general educational information, not operational, legal, or regulatory advice. Rules differ by authority and change over time. Always verify against current official sources and follow your operator's approved procedures.
Flight time runs chock to chock
The headline is that flight time includes taxiing. Both main systems agree on this, almost word for word. EASA's FCL.010 defines flight time, for aeroplanes, as the total time from the moment an aircraft first moves for the purpose of taking off until the moment it finally comes to rest at the end of the flight. The FAA, in 14 CFR 1.1, defines flight time as pilot time that commences when an aircraft moves under its own power for the purpose of flight and ends when the aircraft comes to rest after landing. ICAO Annex 1 frames it the same way. Different wording, identical meaning: first movement to final rest.
That period has a familiar name in operations: block time, also called chock-to-chock or block-to-block, because it runs from the moment the chocks come away and the aircraft moves off the blocks until it parks and comes to rest again. So when you log flight time, you are logging block time. The taxi out to the runway and the taxi back to the apron are both inside it.
Air time is something else
The time the aircraft is actually off the ground, from lift-off to touchdown, is air time. The FAA gives it a precise definition for maintenance purposes under the name time in service: in 14 CFR 1.1, the time from the moment an aircraft leaves the surface of the earth until it touches it at the next point of landing. That is the wheels-off-to-wheels-on figure.
Air time and time in service matter mostly to the aircraft, not to you. Maintenance schedules, component lives and airworthiness intervals are often counted in time in service, because what wears an airframe and engine is flying, not sitting on a taxiway. ICAO Annex 6 and the continuing-airworthiness rules lean on these airborne and block figures for operational record-keeping. Your personal logbook, by contrast, totals flight time, which is block time, so the two records can show different numbers for the very same flight.
The relationship is simple and one-directional: block time always equals or exceeds air time, and the difference is the taxiing. On a long flight from an uncluttered field the two are close; on a short hop out of a congested airport with a long taxi and a queue for the runway, block time can dwarf air time.
Tach, Hobbs and how the numbers get measured
In practice the figures are often read off a meter, and it helps to know what each meter measures, because none of them is the legal definition exactly.
- A Hobbs meter typically runs whenever the engine is running (or oil pressure is up), so it approximates block time reasonably well and is what many rental operators bill against.
- A tach (tachometer) time meter runs in proportion to engine RPM, so it counts a fast cruise close to real time but undercounts taxi and idle, where the RPM is low. Tach time is therefore usually less than block time.
These are convenient approximations, not the regulatory definitions, so a careful logbook records flight time as block time, the period from first movement to final rest, while being aware of which meter the aircraft and the invoice are using.
How this differs from flight time in the duty rules
There is a second sense of "flight time" worth separating off, to avoid confusion with the duty and flight-time-limitation guides. The definition of flight time is the same block-to-block period in both contexts. The difference is what it is used for. In your logbook, flight time is experience you bank toward licences, ratings and recency. In the flight-time-limitation rules, that same block figure is capped, so much flight time in a day, a month, a year, to manage fatigue. One context counts the hours up as a record of what you have done; the other counts them down against a limit. Same clock, two different jobs.
Helicopters measure it differently
The aeroplane definition, first movement to final rest, is not universal across categories, and helicopters are the clearest example. EASA's FCL.010 defines helicopter flight time as the total time from the moment a helicopter's rotor blades start turning until the moment the helicopter finally comes to rest at the end of the flight and the rotor blades are stopped. So a helicopter's flight time is bounded by the rotors, not by the wheels or skids moving, because a helicopter can be doing flight-relevant work, in the hover or air-taxiing, without ever rolling in the way an aeroplane taxis. The principle is the same, the clock covers the whole operation rather than just the airborne part, but the trigger is matched to how the machine actually operates.
Which figure goes where
It helps to hold a simple map of which time is used for what:
- Flight time (block time) is your logbook figure and your flight-time-limitation figure: the experience you bank and the hours that are capped for fatigue.
- Air time (time in service) is mainly the maintenance figure: the airborne hours that drive component lives, inspection intervals and continuing-airworthiness records.
Operators sometimes track both, because they answer different questions, and the same flight legitimately appears as two numbers in two records. Knowing which figure a form, a limit or an invoice is asking for stops you from entering the wrong one. When in doubt, the rule is that your personal experience is flight time, chock to chock, and the airframe's wear is time in service, airborne only.
A worked example
You fly a local navigation exercise. The times go like this:
- you first move off the parking spot (off-blocks) at 10:00;
- you lift off at 10:10;
- you touch down at 11:00;
- you park and come to rest (on-blocks) at 11:08.
Your flight time, which is block time, runs from first movement to final rest: 10:00 to 11:08, which is 1 hour 8 minutes, logged as roughly 1.1 hours. Your air time, lift-off to touchdown, runs 10:10 to 11:00, which is 50 minutes, about 0.8 hours. You were airborne for 50 minutes, but you log 1.1 hours of flight time, because the 10 minutes taxiing out and the 8 minutes taxiing in are part of flight time and not part of air time.
Now imagine the same airborne 50 minutes out of a busy international airport, with a 20-minute taxi to a distant runway, a hold for departing traffic, and a long taxi back to a remote stand. The air time is still 50 minutes, but the block time might be 1 hour 40 minutes or more. The flight felt identical in the air; the logged flight time, and the maintenance time in service, diverge sharply because of the ground time the busy field added.
Common pitfalls
- Logging only the airborne time. Flight time is block time and includes taxiing, so you would undercount your hours.
- Confusing block time with air time. Block time runs chock to chock; air time is wheels-off to wheels-on, for maintenance.
- Treating a meter as the definition. Hobbs approximates block time and tach time undercounts taxi; the logbook figure is block time itself.
- Mixing the logbook and the FTL sense of flight time. The definition is the same block period, but one banks experience and the other counts against a limit.
- Assuming the aircraft record and your logbook agree. The aircraft may track time in service while your logbook totals flight time, so the same flight shows two numbers.
In Pilot EFB
Pilot EFB keeps your flight time as block time in the electronic logbook, the way the rules define it, and completing a flight can generate an entry for you to review and confirm rather than retype. It is a convenient personal record, not a compliance system: you check the times against the rule for your licence and reconcile them with any logbook your operator or training organisation treats as the official record, and with the aircraft's own maintenance record where that tracks time in service. Saved entries stay available offline. Pilot EFB is offline-first and is not a certified or authority-approved electronic logbook.