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Pe11e

Flight Time Duration & Estimation

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I'm using Aerosoft A319/A320, and it calculates flight time in MCDU, and I add 20 minutes if taxi is normal, or 25 minutes if it's a long taxi at bigger airports. I flew today LSZH - LIMJ (Zurich - Genoa), and exact time of arrival was 59 minutes, let's say an hour, and that is too much for 400km route (filled flightplan). That's exactly an average speed of 400km/h, which is the same as a smaller turboprop plane departing from a GA field (no pushback, short taxi), resulting in same flight time.

 

Before I continue... I know that short flights are not time and fuel efficient, but 1 hour trip for 350-400km route is too much. And I didn't even added holding time on busy airports!

 

I must find again a very useful EXCEL sheet for calculating total flight time, just enter CRZ ground speed (or TAS), average wind (FSGRW has very useful average trip wind info), taxi times, and total flight time will be calculated pretty close. With FsPassengers I was able to hit ETA on every flight with minute or two +/- difference if there wasn't any longer hold than 3-5 minutes.

 

Very simple question, how pilots are calculating exact arrival time (ETA) and flight time from pushback to engines off parking brake set in the real world? Is it calculated by dispatch, with winds, etc?

 

 

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I would venture a guess, for your particular situation that using PFPX can give you what you need.  I believe flight time calcs are in a flight plan created with PFPX.  As far as calculating in the air, I know the PMDG aircraft have a decent feautre in their FMC's for calculating time, just watched a youtube vid on that not too long ago, i think it was by Frooglesim and he was taking a short hop from Orlando to Chicago.  He had shown how you can adjust your flight time in the FMC to arrive earlier or later.

 

-Jim

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I would venture a guess, for your particular situation that using PFPX can give you what you need.  I believe flight time calcs are in a flight plan created with PFPX.  As far as calculating in the air, I know the PMDG aircraft have a decent feautre in their FMC's for calculating time, just watched a youtube vid on that not too long ago, i think it was by Frooglesim and he was taking a short hop from Orlando to Chicago.  He had shown how you can adjust your flight time in the FMC to arrive earlier or later.

 

-Jim

 

Doesn't have PFPX, but this XLS is quite helpful.

 

FlightData%20Sheet%20screen-1_zps3jmfsyh

 

Five simple steps:  route distance, extra time (pushback + taxi + hold), average trip wind, estimated KTAS (average trip speed), and cruise altitude. Extra time is usually between 20 nad 30 minutes, depends on airport size, ground traffic and hold. When you are departing from bigger international hub and arriving on smaller one, go for 25 minutes (pushback 3 minutes + taxi 10 min + possible hold say 5 min + 7 minutes taxi at arrival airport = 25 minutes extra time), 30 minutes for two big hubs, and 20 minutes for smaller hubs.

Wind comp is an average trip wind. Positive numbers are tailwind, negative headwind. FSGRW has an option to calculate average trip wind, I insert that number here and it will directly affect total flight time. 

Estimated KTAS is a bit tricky, generally it's an average trip speed (250 under 10000 + 280 climb + cruise speed + 280 descent + 250 under 10000). FsPassengers will calculate an average trip speed at the end of every flight, so it's easy to find an average number after two/three flights.

Cruise altitude is self explanatory, and it will also affect total flight time.

 

It is quite rewarding when you calculate ETA perfectly, and hit the parking brake with a one minute difference. I must add that flying without given ETA is less interesting. This way you are trying to adapt speed to match ETA, but it depends on your cost index. ;)

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Using PFPX for two weeks so far, I still can't nail the ETA calculations. First of all I'm using flight plans without SIDs and STARs, I love to be vectored after takeoff and on approach, using PFE. PFE loves sometimes to give you vectors for a long ILS approach, resulting a few minutes late gate arrival.

My settings in PFPX are - 15 mins taxi out, 10 minutes taxi in, let PFPX load the FSGRW weather for wind compensation calculation, and I must manually add few waypoints to make the route longer about 10-11% to compensate eventual long vectored ILS approach. That way I can hit the ETA at the gate, withing the minute or two if I'm lucky, but I'm still finding the right values.

 

I'm pretty sure this method to make 10-11% longer are weird, but only that way I can get accurate ETA after Compute Flight.

 

Oh, I found out right now about circle out/circle in distances, I guess that is all about vectoring?  :smile:

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