Block time vs flight time: what's the difference?

The names come from the wheel chocks (the blocks) placed against the tyres at the gate. "Off blocks" is when the aircraft leaves the gate and "on blocks" is when it parks at the other end. Block time is everything in between. Air time, which this guide also calls flight time, is only the part where the aircraft is off the ground.

Block time explained

Block time starts at the first movement away from the gate, usually the start of pushback, and ends when the aircraft comes to a stop at the arrival gate. It includes:

• Pushback and taxi out to the runway
• Any wait at the holding point
• The takeoff, the whole flight and the landing
• The taxi in to the gate

Because it covers the whole job from gate to gate, block time is the figure real airlines build schedules around. The departure and arrival times printed on an airline ticket are gate times, so the scheduled duration is a block time, not an air time.

Flight time and air time

Air time runs from the moment the wheels leave the runway to the moment they touch down. It is the time the aircraft is actually flying, and the part of the trip spent off the ground.

"Flight time" is the slippery term. In this guide it means air time, but some real pilot logbook rules define it much closer to block time, from when the aircraft first moves under its own power until it stops after landing. When you compare numbers from different sources, check which definition each one uses.

A worked example

Here is one flight with four timestamps, the same four that airlines record as OOOI times:

From those you get:

The 27-minute gap between block time and air time is all ground time. At a busy airport with a long taxi or a queue for the runway, that gap can easily be 40 minutes or more on a short flight.

Why real airlines use both

Real airlines care about the two numbers for different reasons. This is how they use them; it isn't guidance for real operations.

• Block time is the basis for schedules, how many flights an aircraft can do in a day, and at some airlines crew pay and duty records. It reflects the whole cost of the flight, including the time on the ground with engines running.
• Air time matters for things that wear only while flying, such as some maintenance intervals, and for comparing how long the airborne part of a route takes.

Airline schedules also pad block times to allow for typical taxi times and delays at each airport, which is why flights often arrive "early" when the taxi is short.

How virtual airlines use block time and flight time

A virtual airline (VA) mirrors this in the sim. When you file a flight, its time is added to your logbook, and if your VA ranks pilots by hours, your total decides your rank, which aircraft you can fly and which routes you can bid on. Our guide to virtual airline ranks explains how that progression can work.

VAs choose which time they count:

• Block time rewards the whole flight, including pushback and taxi. It is closer to how airlines log crew hours, and it gives credit for the time you really spent flying the sim session.
• Air time counts only the time airborne, so it is harder to inflate by sitting on the ground with the engines running.

Pauses, sim rate and other edge cases

A sim session can include things a real flight never does, so a VA needs rules for them:

• Pausing. Paused time isn't flying time, and we'd recommend a VA doesn't count it.
• Sim rate. Flying at 2x or 4x speed shortens the real time a flight takes. We'd recommend counting only real time, so a two-hour flight at 4x counts as about 30 minutes.
• Disconnects and reloads. A crash or reload mid-flight can corrupt times, which is why good tracking software checks that the flight was continuous.
• Diversions and fuel stops. If you land somewhere else, refuel and carry on, check whether your VA logs it as one flight or two.

How tracking software captures each time

An ACARS client can't see wheel chocks, so it uses the aircraft's movement instead. It marks block off when the aircraft first moves, takeoff when it leaves the ground, touchdown when the wheels meet the runway, and block on when it stops at the gate. Those points come from the same logic that detects the phases of flight.

Frequently asked questions

Does block time include taxi time?

Yes. Block time covers taxi out and taxi in as well as the time in the air. That is the main difference from air time.

Is the flight time on my airline ticket block time or air time?

Block time. The times on a ticket are gate departure and gate arrival, so the duration between them includes taxiing.

Why is block time longer than flight time?

Because block time adds the time spent on the ground at both ends: pushback, taxi out, any wait for the runway, and taxi in. On a short flight at a busy airport this can be a large share of the total.

Does time compression count towards my virtual airline hours?

That depends on your VA. If it counts real time, as we'd recommend, a flight flown at 4x sim rate earns about a quarter of its normal time. Some VAs do allow it, so check the rules.

Which time counts towards my VA rank?

Whichever one your VA has chosen to log. Some use block time, others air time. Your VA's pilot handbook or rules page should say.

Where Stratos fits

Stratos records the block-off, takeoff, touchdown and block-on moments of every flight automatically and sends the flight time with your PIREP, using block time (pushback to arrival at the gate) or air time (takeoff to landing) depending on your VA's Time Capture setting. A brief sim dropout is folded into paused time rather than credited as flying, and time compression only counts as real time if the airline turns that on. The VA onboarding guide lists the time capture settings airlines can choose.