Flight Time Question

MiloDublin

Is flight time calculated from when the aircraft leaves/arrives at the stand or takes off/lands?

Jack1985

MiloDublin wrote: »

Is flight time calculated from when the aircraft leaves/arrives at the stand or takes off/lands?

Block to Block so yes when the aircraft push's back from its stand it ''departs'' and upon arrival at the gate at the given destination the flight ''arrives'' - Runway to Runway time is also timed as total airtime.

Stovepipe

Flight time is defined as from when the aircraft moves off under it's own power to when it comes to a complete, permanent halt after the flight, ie, chock to chock. Airlines call it block time (brakes off to brakes on). Some people will tell you that it is from when the engine(s) is/are started and shut down or when full power is applied, but that is not the case. If you have any doubt, it's in Irish Air legislation and the IAA will be happy to point it out to you.

regards
Stovepipe

St. Leibowitz

Stovepipe wrote: »

Flight time is defined as from when the aircraft moves off under it's own power ... ie, chock to chock. Airlines call it block time (brakes off to brakes on). Some people will tell you that it is from when the engine(s) is/are started ... but that is not the case. If you have any doubt, it's in Irish Air legislation and the IAA will be happy to point it out to you.

regards
Stovepipe

defined as from when the aircraft moves off under it's own power ... surely the engine(s) need to be started for that ??

L1011

St. Leibowitz wrote: »

defined as from when the aircraft moves off under it's own power ... surely the engine(s) need to be started for that ??

Engines are started before the aircraft is moving, though.

owenc

MiloDublin wrote: »

Is flight time calculated from when the aircraft leaves/arrives at the stand or takes off/lands?

I think each airline is different but on most of the flights i'm on the time is from the plane lifting off to touching the ground.

Irish Steve

It gets slightly more complicated in some cases. While for the pilot, the times recorded are brakes off to brakes on, the engines and props logs are airborne time, which is deemed to be from start of take off roll to end of landing roll, and on an engine that has relatively low time between overhauls, this subtle but significant difference can mean a number of extra flights, especially when operating from a larger airport where the taxi time can be considerable.

On several occasions, when I was operating a light twin in and out of Brussels, the taxi time for departure could be as long as 30 minutes, which is logged as part of the flight, but not as part of the engine and prop operating times.

In the same vein, in the winter, on prop engines, there can be quite some time spent with the engines running at idle, but on stand or a remote holding point, waiting for oil temperatures to come up to the green before carrying out engine power runs and prop feather checks. If the aircraft has moved, then that time waiting on the remote holding point is part of the flight, but if it's still on stand, then it's not.

Some flying clubs operate on the basis of the time recorded on the (in)famous Hobbs meter, which is usually alive when the engine is running, which is something to watch out for if you are using a club aircraft to visit a busy airfield, as the total cost of the flight can be considerably more than you were expecting it to be based on block time or airborne time. From a legal point of view, that also can be a problem, in that if you've paid for (say) 1 Hr 10 minutes, you'd expect to be logging 1 Hr 10, but it's very likely that the flight time was only 1 Hr, and the airborne time might well have been 50 minutes. Nice for the flying club, in that in that scenario, they've "won" 20 minutes of time that was not put on the engine and other items, which is the time used when working out when to get things like 50 Hr checks done .

It's not unknown for some instructors to wait until the engine is running before launching into a long and complex pre flight briefing or discussion, and if the times are based on the Hobbs, now you know why.

owenc

Jack1985 wrote: »

Block to Block so yes when the aircraft push's back from its stand it ''departs'' and upon arrival at the gate at the given destination the flight ''arrives'' - Runway to Runway time is also timed as total airtime.

Well not with United.

I timed my flight and it was 6 hours and 40 mins which was the exact same as what flight aware registered.. if United Airlines had measured the time from pushback to arriving at the gate the flight would be much longer..
I don't see why airlines do this anyway as the airplane isn't actually in the air when it is pushing to a gate.

Jack1985

owenc wrote: »

Well not with United.

I timed my flight and it was 6 hours and 40 mins which was the exact same as what flight aware registered.. if United Airlines had measured the time from pushback to arriving at the gate the flight would be much longer..
I don't see why airlines do this anyway as the airplane isn't actually in the air when it is pushing to a gate.

United is block to block.

folbotcar

Like Stovepipe says mainly it's mainly brakes off to shutdown. But for the pilots it's often start up to shut down and sometimes as long as the engine is running. Let's face it, if someone walks into your prop before you move you will be described as the P1 in the accident report. So you might as well log it.

Tenger

owenc wrote: »

Well not with United.

I timed my flight and it was 6 hours and 40 mins which was the exact same as what flight aware registered.. if United Airlines had measured the time from pushback to arriving at the gate the flight would be much longer..
I don't see why airlines do this anyway as the airplane isn't actually in the air when it is pushing to a gate.

You timed your journey on your flight. The airline's publish scheduled block times based on historic data, winds seasonality and flight planning requirements. Nothing to say that the flight the day before or after yours wasn't 15 mins longer or shorter. And we have all seen that FlightAware isn't 100% all the time.

Actual time of departure is leaving the gate, actual time of arrival is stopping on the gate. These are the times that are important for the passengers in relation to on time/late and making connections.

If an Aer Lingus A320 took off from Dublin and flew to Heathrow as per flight plan and climbed and descended unrestricted and there were no other aircraft or delays the flightplan time is 43mins. That's the basic time from that you add delays and get the scheduled flight time.

By delays I mean push back and start, taxi time, hold time, enroute delays, holding delays, taxi delays etc etc etc etc.

billie1b

[Deleted User] wrote: »

If an Aer Lingus A320 took off from Dublin and flew to Heathrow as per flight plan and climbed and descended unrestricted and there were no other aircraft or delays the flightplan time is 43mins. That's the basic time from that you add delays and get the scheduled flight time.

By delays I mean push back and start, taxi time, hold time, enroute delays, holding delays, taxi delays etc etc etc etc.

Whats the averag taxi time in LHR these days?

Skuxx

So would it be correct to say, when Ryanair play their jingle stating another on time arrival as soon as you touch down, you technically haven't arrived on time until brakes are on at the gate??

Tenger

Skuxx wrote: »

So would it be correct to say, when Ryanair play their jingle stating another on time arrival as soon as you touch down, you technically haven't arrived on time until brakes are on at the gate??

Technically yes, arrival is on gate.

Jack1985

billie1b wrote: »

Whats the averag taxi time in LHR these days?

Anywhere between 10 and 30 minutes some evenings, you'd feel like your on the ground longer than in flight on occasion!

Irish Steve

A while back, the best flight from LHR used to be the 22 or 2300 (I think) departure to Dublin, it was the last flight out of the evening, and back in the T1 days, it wasn't unusual to be less than 5 minutes from brakes off to airborne, especially if the aircraft was on the right gate and could take an intersection departure from 27R, which we did on a few occasions, I suspect the longest delay was the time needed to complete the after start checks before departure. I think the fastest was 3 minutes on one occasion, we literally pushed back, the tug was off, and it was a rolling intersection departure from very close to the stand location. Very much the exception though

Heathrow ATCO on twitter says they will miss fungus being out of T1 said it was great having them go from A5 and A6.

Reference taxi times Heathrow ATC are good at holding traffic on stand if there is an issue downstream in an attempt to minimise the taxi time delay. As others have said it's very short to 30-40 mins on average. But that's an average.

Stovepipe

In the case of an aircraft at a gate, it's obviously going to be pushed back by a tug and then cast off. Until then it is under the control of the tug driver, as he is responsible for positioning it. When the tug is clear and the pilot acknowledges this by waving to the crew, he can then depart under his own power. What happens is that, for convenience and to stop arguments about start/stop time or block time or whatever, the aircraft sends a signal to the Company computer when the park brake is released (to allow the tug to push) and block time starts counting. Ideally, the aircraft is then pushed and released without delay and taxis off. In the real world, it takes a few minutes and there are always delays, but in effect, the flight has started. When the pilot applies the park brake at his destination gate, the aircraft again sends a signal to the effect that it has arrived and the block time stops counting. This is independent of the engine running time, which is obviously longer than the block time and also because engineers may have run the engines on the ground.Block time effectively exists for the convenience of airlines, because the timing they are most concerned about is flight cycles, which is a different animal altogether.
Now, if you are sitting in your Cessna at an airfield, you are not concerned about block times or cycles but you will invariably start your timer as soon as you start your engine, allow it to warm up and then taxi. If you are honest, you will log chocks away to chocks back. In either case, it's a bit of a fudge because it includes taxying time, which is strictly not flying but the logic is that the aircraft is operating, warming up and the systems are operating (which is eating into their component lives) and is under pilot control. So, block to block for airlines, chock to chock for little aeroplanes, which effectively amounts to the same thing in the end.

Irish Steve

Depending on the airport, yes, the block time starts with brake release, but the engines may well not be started for several minutes, depending on things like the route off stand, the power of the tug, (ever tried pushing a 777 with both engines running on a wet or icy ramp?), and the airport rules, Dublin for example has a number of engine start points, and the aircraft is not allowed to even begin starting until beyond the ES points, to avoid things like blast damage to other aircraft or ground equipment. It can get very complicated if the aircraft has a defective APU and needs a ground assisted air start, as that normally has to be done on stand, for safety reasons. in that case, one engine is started on stand, and then the aircraft is pushed out, with the engine at ground idle until the equipment is clear, when a higher power setting is then needed to start the other engine using cross bleed.

On small aircraft, the life of engines and props (TBO, time between overhaul, link ) is calculated on air time, so time warming up, taxiing and doing anything other than committing aviation is extra and not logged. That can be very important on some piston engines, where the TBO can be as low as 1200 hours, and the overhaul is mandatory, and expensive. One particular helicopter engine the TBO is 600 Hrs. In Europe, warm up time is usually not long, but in other climates, the time to "ready" can be significant.

To keep the math simple, 30 minute taxi, 30 minute flight, on a TBO of 1200 Hrs would be 2400 flights, but if taxi time was included, then it's 1200 flights. Clearly that has a huge impact on the total operating cost. Same concept applies to props, regardless of it being piston or turbine, and while the intervals are a LOT longer, turbines are also inspected on a similar basis.

Smaller aircraft don't normally have the "cycles" limits, primarily because they tend not to be pressurised, so don't have the same issues that apply to pressurised aircraft.

fr336

Skuxx wrote: »

So would it be correct to say, when Ryanair play their jingle stating another on time arrival as soon as you touch down, you technically haven't arrived on time until brakes are on at the gate??

Oh no, evil Ryanair are at it again with their low fares and on time flights.

Stovepipe

It ain't over til the fat lady sends the ACARS message that the parking brake has been applied. everything else is just noise.

Tenger

fr336 wrote: »

Oh no, evil Ryanair are at it again with their low fares and on time flights.

MOD.......Interesting thread....no need for trolling...MOD

fr336

Tenger wrote: »

MOD.......Interesting thread....no need for trolling...MOD

Yeah trolling was definitely the intention. Not rolling eyes on fashionable FR bashing. I suggest we leave it here though mod..don't want to go too off topic

smurfjed

For us, its brakes off to brakes on, some decided that this was a perfect way to earn a little bit more money, they could release the parking brake early and hold the aircraft on the toe brakes, same when they blocked in, keep the toe brakes until chocked, few minutes later apply the parking brake. Do this on 4 sectors in one day and one could earn an extra 1 hour of credit pay. 15 -20 days of working in a month and people were looking at serious extra money. This cunning little stunt didn't last for long and the worst offenders were invited to leave.