The International Simutrans Forum

 

Author Topic: Aircraft turnaround times  (Read 399 times)

0 Members and 1 Guest are viewing this topic.

Offline jamespetts

  • Simutrans-Extended project coordinator
  • Moderator
  • *
  • Posts: 19952
  • Cake baker
    • Bridgewater-Brunel
  • Languages: EN
Aircraft turnaround times
« on: February 09, 2020, 12:12:14 PM »
Discussions have taken place on the Stephenson-Seimens server regarding aircraft turnaround times. It was agreed that it would be useful to start a thread where information on this topic could be gathered and exchanged.

So far, I have found the following: this article regarding an American Airlines A321, giving a time from arriving at the gate to departing from the gate as circa 70 minutes (discounting the fact that this particular example arrived early).

This article from the Daily Telegraph in 2019 gives the following data:(1) low cost short haul carrier Ryanair (which only uses Boeing 737 type aircraft) have reduced their turnaround time to 25 minutes by removing seat-back pockets, thereby reducing the time spent to clean the aircraft;(2) British Airways typically takes 50-60 minutes to turn around a short haul flight;(3) Norwegian takes 90 minutes for long-haul flights, but this "starts an hour before the aircraft arrives at the gate", so this is unreliable as an indication of the total dwell time at the gate.
According to this website, "turnaround time" refers to the time between landing and takeoff, whereas what we need is the gate dwell time, so some care is needed with "turnaround" figures.

According to this article, aircraft turnaround time has increased in recent years. See also this diagram for some graphs and visualisations.

I believe that the existing timings in the pakset are based on passenger boarding/disembarkation times only. I believe that Giuseppe has spent some time in working these out, so, ideally, these should be integrated into any revised timing. Thus, what we need to do is to add these times to an estimate of the time spent in other operations. Some operations, such as refuelling and loading/unloading passenger baggage, can take place simultaneously with passenger boarding/disembarkation, so the really important things are the things that cannot be done with passengers aboard, which seem to be (according to the first linked article) the cabin cleaning and catering restocking.

On the American Airlines A321 example, the aircraft arrived at the gate at 0835h and the last passenger disembarked at 0855h. Catering arrives at 0903h, although it is implied that cleaning has not entirely finished at this time. By 0926h, passengers start to board again. They finish boarding by 0955h.

Thus, we have:
* disembarkation: 20 minutes;
* cleaning (exclusive): 7 minutes;
* catering/cleaning: 21 minutes;
* boarding: 29 minutes.

This gives a total of 77 minutes, of which 28 minutes were spent without boarding or disembarkation, the total boarding/disembarkation time being 49 minutes. 36% of the at gate turnaround time was therefore time spent other than boarding/disembarkation.

There is an Airbus A321 in the game. This has a loading time of 2,400 seconds, or 40 minutes. Given the fluctuations in boarding times over time, this suggests that Giuseppe's estimates of basic boarding/disembarkation times are not too far off and can safely be used as the basis for extrapolation by the addition of cleaning/catering time.

Further, we can sensibly assume that aircraft that need no catering have a reduced turnaround time, that the greater the quality the provision of catering, the greater the turnaround time, and also that the cleaning and catering provision part of the turnaround time will scale with the number of passengers. Given that the existing times also scale with the number of passengers, we should be able to modify the turnaround times to something in the region of the following:

* no catering: current times +20%;
* level 1 catering: "" + 25%;
* level 2 catering: "" + 30%;
* level 3 catering: "" + 36%;
* level 4 catering: "" + 42%;
* level 5 catering: "" + 50%.

This would give a turnaround time of 54 minutes to the Airbus A321 in the game, which is probably not far off its ideal minimum realistic at gate turnaround time.

Offline Freahk

  • Devotee
  • *
  • Posts: 1159
  • Languages: DE, EN
Re: Aircraft turnaround times
« Reply #1 on: February 09, 2020, 02:13:04 PM »
Wow that is by far more preciese data than I had expected.
It also fits my expectations of roughly the larger the airplane, the longer the turnaround times.

Btw. can we distinguish in between disembarkation times, cleaning/catering times and boarding times?
The latter two would affect passengers jorney times whilst cleaning/catering does not.
And exactly does the checkin/checkout, simmulated by passengers minimum transfer time at airports work?
It is quite important to understand this properly before I can tell if the above described turnaround time balancing makes sense.
« Last Edit: February 09, 2020, 04:25:52 PM by Freahk »

Offline jamespetts

  • Simutrans-Extended project coordinator
  • Moderator
  • *
  • Posts: 19952
  • Cake baker
    • Bridgewater-Brunel
  • Languages: EN
Re: Aircraft turnaround times
« Reply #2 on: February 09, 2020, 03:27:54 PM »
The boarding times (for all forms of transport) are not simulated directly. The stop dwell times are simply the times that vehicles must spend stationary at a stop. For passengers, mail and goods, it matters not when they arrive at the stop: if the convoy has not finished boarding (or if it is reversing or waiting for clearance having not yet departed), it is available for loading. The actual loading time is not simulated, so this is assumed to be instant.

The airport minimum wait times are simulated by adding these times to the journey times in the route calculations and, if I recall correctly, adding these to the transfer times at airports, so that passengers do not become available to board an aircraft (i.e. are assumed to be in a queue for security, checking in their baggage, walking to the gate, etc.) until this minimum time has elapsed.

Thus, there should be no need to simulate specifically the cleaning/catering time for aircraft.

Offline Vladki

  • Devotee
  • *
  • Posts: 3370
    • My addons, mostly roadsigns, pak128.cs
  • Languages: EN, CS
Re: Aircraft turnaround times
« Reply #3 on: February 09, 2020, 07:36:16 PM »
How about combined stop with all means of transportation (air, ship, train, bus) is the airport waiting penalty (security check) applied only to the airline passengers? Are e.g. transfers from train to bus affected or not (if the station includes airport)?

About the cleaning, trains and buses have to be cleaned, refueled etc too. But usually they aren't at every stop as planes do. So adding these times only to the airplanes would be a bit unfair.

Offline jamespetts

  • Simutrans-Extended project coordinator
  • Moderator
  • *
  • Posts: 19952
  • Cake baker
    • Bridgewater-Brunel
  • Languages: EN
Re: Aircraft turnaround times
« Reply #4 on: February 09, 2020, 08:41:01 PM »
How about combined stop with all means of transportation (air, ship, train, bus) is the airport waiting penalty (security check) applied only to the airline passengers? Are e.g. transfers from train to bus affected or not (if the station includes airport)?

About the cleaning, trains and buses have to be cleaned, refueled etc too. But usually they aren't at every stop as planes do. So adding these times only to the airplanes would be a bit unfair.

I have not looked at this code in a long time, but I do believe that the airport minimum wait is applied only to passengers boarding aircraft.

As to other vehicles, there is a plan, which I hope to implement with the new convoy scheduling features, to have differential waiting times between an ordinary stop and a range stop, there being one range stop required once every X kilometres that a vehicle travels, X being the vehicle's range. This should account for refuelling (etc.) time.

Offline Freahk

  • Devotee
  • *
  • Posts: 1159
  • Languages: DE, EN
Re: Aircraft turnaround times
« Reply #5 on: February 09, 2020, 10:34:12 PM »
Also note this quite informative source:
https://eu.azcentral.com/story/travel/airlines/2019/05/14/how-long-it-takes-to-get-a-plane-ready-between-flights-airplane-turnaround-time/1123694001/
It doesn't tell us many news apart from mentioning a 10 minute turnaround time.

I have searched for "10 minute turnaround" explicitly and found some quite interessting articles about that, one of these being https://www.cnbc.com/id/43768488

So indeed, they made it to get turnaround times down to 10 minutes at a boeing 737 in 1971
These days, they still make it in 25minutes, thus I would suggest setting the turnaround time of non-catering 737 down to 25 minutes.

Further, this confirms the 16:40 turnaround times of the rather small turoprops are likely realistic.

Further note the "Southwest Turnaround" section of the following https://econlife.com/2016/12/fast-turnaround-time/ explicitly stating that southwest did not offer inflight meals
The other sections are advert...

Basically I agree with the point that catering will grow turnaround time. However, I don't think different levels of catering will have such a huge impact, further I don't think the difference in between no catering at all and level 1 catering is that small. Any kind of catering will require attaching a food delivery container while loading the airplane.
If they just move a few snacks from the container to the airplane or a few boxes of pre-cooked 5-star menues won't change a lot in loading times.