donder10
Posts: 6944
Joined: Sun Oct 21, 2001 5:29 am

How Do Airlines Create Timetables?

Wed Feb 21, 2001 6:22 am

How do large airlines such as British Airways work out their timetables and what plane-type will service each route?When I looked at a list of Heathrow movements of a whole month I see a different plane flying some long-haul flights each day.Why not have 1 plane operate the same route each day?How long does it take a 747-400 to turn around?Thanks,alex
 
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RE: How Do Airlines Create Timetables?

Wed Feb 21, 2001 5:15 pm

How long does it take a 747-400 to turn around?


As long as it takes the pilots to do a three-point turn.
 
mick
Posts: 47
Joined: Wed Jan 17, 2001 12:23 am

RE: How Do Airlines Create Timetables?

Wed Feb 21, 2001 7:41 pm

I suppose they have very complex computer that does the timetabling. The type of craft would pretty much be determined by the forcast traffic on that route and also the requirements - ie three class / four class setup.

For the aircraft utilisation its best to look at Virgin (BA has to many planes going to too many places). So if we start with Jan 01 you will see the following occur (thanks to stephenj for his website!):

We'll look at G-VBIG (a 744). During the first couple of days it did the following flights:

Flight Destination / Origin A/C Type Date Time Time@LHR
VS0004 From JFK, New York G-VBIG 744 01/01/01 07:10
VS0001 To Newark, Nj, USA G-VBIG 744 01/01/01 16:00 08:50

VS0002 From Newark, Nj, USA G-VBIG 744 02/01/01 09:25
VS0003 To JFK, New York G-VBIG 744 02/01/01 14:00 04:35

VS0004 From JFK, New York G-VBIG 744 03/01/01 07:00
VS0021 To Washington Dulles G-VBIG 744 03/01/01 11:30 04:30

VS0022 From Washington Dulles G-VBIG 744 04/01/01 07:05
VS0019 To San Francisco, USA G-VBIG 744 04/01/01 11:00 03:55

Total Time @ LHR 21:50
So if we look at that it had 21:50 hours on the ground at LHR and travelled JFK-LHR-EWR-LHR-JFK-LHR-IAD-LHR-SFO (8 legs total)

Now if it had done just the EWR-LHR-EWR 4 times (ie 8 legs) (VS1 and VS2) it would have looked like this:
VS0002 From Newark, Nj, USA G-VBIG 744 01/01/01 09:25
VS0001 To Newark, Nj, USA G-VBIG 744 01/01/01 16:00 06:35

VS0002 From Newark, Nj, USA G-VBIG 744 02/01/01 09:25
VS0001 To Newark, Nj, USA G-VBIG 744 02/01/01 16:00 06:35

VS0002 From Newark, Nj, USA G-VBIG 744 03/01/01 09:25
VS0001 To Newark, Nj, USA G-VBIG 744 03/01/01 16:00 06:35

VS0002 From Newark, Nj, USA G-VBIG 744 04/01/01 09:25
VS0001 To Newark, Nj, USA G-VBIG 744 04/01/01 16:00 06:35

Total Time @ LHR 24:20
As you can see the total time the plane is on the ground at LHR has increased to 24:20 hrs over a four day period. I'm not sure how much it costs to have a 744 sitting on the ground at LHR but i reckon it wouldn't be cheap. The name of game is to get the plane in the air earning fares, not sitting on the deck at LHR costing a fortune.

This assumes that schedules are met (yeah right) and also that they turn the plane around in the NON-LHR airport immediately and send it back to LHR.

So you've added this level on complexity to the equation and i haven't even looked at pilot/crew hours etc....

If you complete a similar exercise with BA you should be able to see what is going on!

I hope this explains why they don't fly one route all of the time.

This aside - just a small bit of info. It doesn't always work like this - if you look at the BA744 leased to QF for their IFE upgrades - it only does the SYD-HKG route always! Why ??? I believe it has something to do with different galley configurations and seating.

Cheers

Mick
 
mick
Posts: 47
Joined: Wed Jan 17, 2001 12:23 am

RE: How Do Airlines Create Timetables?

Wed Feb 21, 2001 7:48 pm

Oh i should tell you this

I don't work for an airline and have based this entirely on data available on the net (probably the site you were looking at!)

So i'm only guessing but i think its a fair guess. I've also wondered myself about this and decided to do the analysis after you asked.

Cheers

Mick
 
JG
Posts: 165
Joined: Tue Jun 07, 2005 1:53 am

RE: How Do Airlines Create Timetables?

Wed Feb 21, 2001 10:18 pm

As far as timetables are concerned and not really discussing the mechanics of aircraft routing and turnaround.

A previous post was correct, an airline operating multiple equipment types will place an approriate number of seats on a segment. If traffic loads differ through the week you will see different aircraft on those segments as the airline manages yield. For that reason it is just not efficient to have one plane operating a route.

You may also notice that the same segment on will vary in time depending on the day of the week. Airlines will generally keep statistical data on their flights to be able to provide accurate timetables. After all it is a customer service business. Flight time, without respect to weather, remains fairly constant... anticipated ground delays become the padding in schedule. I have seen the same SHORT segment into KLGA vary more than 25 minutes all because of anticipated ground delay.

(When I said and airline is a customer service business, I feel compelled to add for the non airline readers that it is in the transportation industry, not the food service industry.  Smile )

Hope this shed a dim light on your questions.

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