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Author Topic: Delays  (Read 1819 times)

Offline ChuckPerry

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Delays
« on: April 15, 2012, 02:50:05 AM »
Okay guys.. I have a question.. I have a MD90 flight from MSY to DEN... the outbound leg has little or no delays..I have been having numerous delays on the return leg caused by "Scheduling- too short turn-around"... I've increased the turn time little by little and I'm up to 75 minutes with a ~1% probability of delay whatever that means.. and I'm still getting significant delays.. How long does it take to turn a MD-90 ??? 

Offline Erik

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Re: Delays
« Reply #1 on: April 22, 2012, 09:55:00 AM »
What airport are you serving to? It could depend on the traffic at that airport.



Offline Jona L.

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Re: Delays
« Reply #2 on: April 22, 2012, 10:02:03 AM »
What airport are you serving to? It could depend on the traffic at that airport.

I have a MD90 flight from MSY to DEN...

New Orleans to Denver ;)


As to the original question:
the ~1% means that the delay probability due to scheduling is around (~) 1%. I takes no longer the 30-40 minutes to turn it in real life, but in AWS you need more, because you cannot treat your staff like sh*t here :P

If you turn it without pressing your staff to bring 200% performance you are fine with 70-75 minutes.

You should keep in mind, that you have to have these 70 minutes between the flights at your home base as well! This may lead to passed-on delays to later flights, or in worst-cases cancellations.


About the issue itself: I came to the point of not looking at delay reason, but only their total number, because it seems somewhat random how they are determined...

Offline swadeepc

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Re: Delays
« Reply #3 on: April 22, 2012, 11:00:27 AM »
will airwaysim ever solve this problem of turnaround? it's stupid really to fly a one hour flight with 747 and having to sit there at destination for 3 hours before flying back!! even longer than the flight time to and back! in real life low cost turn around in 30 mins with A320!! they seem to get by alright with not so many delays.

Offline Jona L.

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Re: Delays
« Reply #4 on: April 22, 2012, 12:02:38 PM »
will airwaysim ever solve this problem of turnaround? it's stupid really to fly a one hour flight with 747 and having to sit there at destination for 3 hours before flying back!! even longer than the flight time to and back! in real life low cost turn around in 30 mins with A320!! they seem to get by alright with not so many delays.

LH can turn their 733 in 15-20 minutes, and 320s in 20-25 minutes... RYR has 15, maximum 20 minutes for their 738s... but this is AWS, not reality ;)

Offline Infinity

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Re: Delays
« Reply #5 on: April 22, 2012, 07:15:37 PM »
LH can turn their 733 in 15-20 minutes

And who told you this bulls*** now?

Offline Erik

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Re: Delays
« Reply #6 on: April 22, 2012, 07:47:52 PM »
Haha, guess I was a bit to fast on the reading there. Sorry about that :-\

LH can turn their 733 in 15-20 minutes, and 320s in 20-25 minutes... RYR has 15, maximum 20 minutes for their 738s... but this is AWS, not reality ;)


Surely it depends how long the flight is. If your flying FRA-DUS which is a 40-50min voyage, usually re-fueling; perhaps also catering, isn't necessary. For that flight i'd reckon you'd need atleast 20-25 minutes, doubt that it can make it in 15-20min.
If you have a flight with 20 pax, surely the cabin will be ready before a flight that has 120pax.
So (at least in reality) there is a big variety on the turn-around times depending on ATC, Ground-handling, catering, re-fueling, you name it.

Quote
keep in mind, that you have to have these 70 minutes between the flights at your home base as well

This is also an import factor which he mentioned, try to keep at least 10-15 minutes between once the aircraft is actually ready and your next service.



Offline alexgv1

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Re: Delays
« Reply #7 on: April 22, 2012, 08:54:35 PM »
In Southwest's early days, when they sold an aircraft and went from 3 dow to 4, to fly the same schedule they increased utilisation and reduced turnaround times. They managed it, and this was partly achieved by a 15 minute turnaround on their 737-200s (same size as 737-500s LH flies). However it was no easy task and took a lot of effort from the staff so when they got more aircraft, 20-25 minutes became more common. Keep in mind they flew on average 400nm legs back in those days. Thus SWA invented the 25 minute turnaround on the 737.
CEO of South Where Airlines (SWA|WH)

Offline Jona L.

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Re: Delays
« Reply #8 on: April 22, 2012, 09:16:29 PM »
And who told you this bulls*** now?

Seen it with my own eyes, mate ;)

waiting for a flight at an airport is more than just sitting around, if you open your eyes ;)

A couple of times when I waited for flights in DUS, I had seen planes that freshly landed from whatever places, unboard and re-board within 15 minutes. Admitted, the plane was not that full, a 733 out of which roughly 50 PAX came, and another 70 (including me) boarded again. I dunno where that plane came from, but all passengers were seemingly routined business flyers (considering that they all wore suits), which made a fast turnaround possible. The plane came in at roughly 0845, and by 0900 the door was closed, and pushback began. To me that is a 15 minute turnaround... dunno how you define it though.

Also in GDN (Gdansk, northern Poland), I had been on a scheduled 735 which came from DUS to fly back there, which was turned in 20 minutes, by de boarding through the rear exit, while passengers were boarding the front one. Worked only because we were told to board by seating row (so they rolled through the plane basically). As it was an outstation cleaning was not really done, but LH passengers are usually civilized people, that don't make much dirt.
PAX-on-board refuelling happened (which only means a fire truck is waiting behind the plane to be there immediately if something happens) catering on outstations also only happens on long haul, for short hops they have the sandwiches for both legs on board.

So two examples I have eyewitnessed, which as from the routine of the crew with that, seems to happen more often than you may think.

Also a friend of mine, who is a pilot in-training with LH says they are trained to do the preparations for the next leg in that timespan.

In Southwest's early days, when they sold an aircraft and went from 3 dow to 4, to fly the same schedule they increased utilisation and reduced turnaround times. They managed it, and this was partly achieved by a 15 minute turnaround on their 737-200s (same size as 737-500s LH flies). However it was no easy task and took a lot of effort from the staff so when they got more aircraft, 20-25 minutes became more common. Keep in mind they flew on average 400nm legs back in those days. Thus SWA invented the 25 minute turnaround on the 737.

Proofs my point :)

cheers,
Jona L.

Offline Jona L.

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Re: Delays
« Reply #9 on: April 22, 2012, 09:18:09 PM »
[...] If your flying FRA-DUS which is a 40-50min voyage, [...]

In 55 mins you are already in MUC from DUS, never flown DUS-FRA, but I think it is rather 40 than 50 mins :)

Offline JumboShrimp

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Re: Delays
« Reply #10 on: April 22, 2012, 09:45:01 PM »
In Southwest's early days, when they sold an aircraft and went from 3 dow to 4, to fly the same schedule they increased utilisation and reduced turnaround times. They managed it, and this was partly achieved by a 15 minute turnaround on their 737-200s (same size as 737-500s LH flies). However it was no easy task and took a lot of effort from the staff so when they got more aircraft, 20-25 minutes became more common. Keep in mind they flew on average 400nm legs back in those days. Thus SWA invented the 25 minute turnaround on the 737.

But Southwest concentrated in less congested airports where the low turnaround times are probably easier to achieve than airports LH flies to.

As far as turnaround times in AWS, I think it would be interesting to see something like Airline's management ability, that an airline can invest into, which would affect their delays.  So for example, at highest ability achieved, the effective turnaround time (with low probability of delay) could drop to 25 minutes.  It is that the curve with delay probability would shift from 40 min to 25 minutes.

This way, an airline could schedule 40 min turnaround for 737/A320, but with nothing invested in this "ability", the airline would have the current ~25% probability of delay.  With increased "ability" it would drop down to 1% with current 40 min delay.

One aircraft where the turnaround time has bothered me most is 757.  I think 70 minutes is a little excessive there.  I would shrink 757 to something like 55 minutes, and have 767 the same as A300 at 70 minutes.  A330/340 group is probably more appropriate at 80 min than 767, since a typical aircraft is A333, which is much larger than a typical 767 aircraft - 763.

Offline alexgv1

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Re: Delays
« Reply #11 on: April 22, 2012, 09:51:26 PM »
Those turarounds were at KDAL, KHOU and KSAT, so I suppose you could say secondary airports. The only reason I could see affecting turnaround at an airport would be availability of equipment such as fuel trucks or stairs/buses to board and deboard pax. I think fuelling is the time dependant thing as you can only get so much (300 gallons?) per minute, when they started allowing fuelling with passengers on board this sped things up a lot because deboarding and boarding could be done at that same time. The Boeing airport docs on their aircraft have quite detailed information on this.  Anything else like gate availability or taxi time isn't to do with the turnaround but these are more likely problems associated with busy airports which are already modelled in, to some extent.
CEO of South Where Airlines (SWA|WH)

Offline JumboShrimp

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Re: Delays
« Reply #12 on: April 22, 2012, 10:04:58 PM »
Those turarounds were at KDAL, KHOU and KSAT, so I suppose you could say secondary airports. The only reason I could see affecting turnaround at an airport would be availability of equipment such as fuel trucks or stairs/buses to board and deboard pax. I think fuelling is the time dependant thing as you can only get so much (300 gallons?) per minute, when they started allowing fuelling with passengers on board this sped things up a lot because deboarding and boarding could be done at that same time. The Boeing airport docs on their aircraft have quite detailed information on this.  Anything else like gate availability or taxi time isn't to do with the turnaround but these are more likely problems associated with busy airports which are already modelled in, to some extent.

Yes, taxi times are already separated from turnaround times in AWS, and they already reflect longer taxi times at large airports vs. smaller airports.

BTW, off-topic.  related to taxiing: On my last flight on 753 from SJU to EWR, no aircraft in front of us, and the pilot really turned up the engines as the airplane was making a U-turn to the runway.  I don't know if the pilot was testing the cornering ability of the 753  ;)

Offline Infinity

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Re: Delays
« Reply #13 on: April 22, 2012, 10:40:30 PM »
A 15 minute turn on a 737 or A320 can only be achieved if the cabin is not cleaned, there is no refueling and no catering and the following flight is a VERY short hop, as if it is a longer flight, even the cockpit preparations need way longer than 15 minutes.

I have seen Ryanair turn in 15 minutes, and as you may imagine when I boarded the plane it was a total mess from the passengers of the previous flight.
Lufthansa cleans it's cabins on every turn. This alone makes it impossible to achieve a 15 minute turn, and a 25 minute turn is only possible if both flights fly with a very low load factor. A typical LH short haul turn takes at least 40 minutes, emphasis on the at least.

Also, a 15 minute turn can absolutely only be achieved with walk-on gates. Gates with fingers or remote stands with busses just can't do that, period.
A Ryanair flight that turns unloads and loads through 2 doors, a Lufthansa flight at a finger gate only does through one door, making it absolutely impossible to achieve a time even close to that of Ryanair.

Offline Jona L.

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Re: Delays
« Reply #14 on: April 23, 2012, 01:35:13 AM »
A 15 minute turn on a 737 or A320 can only be achieved if the cabin is not cleaned, there is no refueling and no catering and the following flight is a VERY short hop, as if it is a longer flight, even the cockpit preparations need way longer than 15 minutes.

I have seen Ryanair turn in 15 minutes, and as you may imagine when I boarded the plane it was a total mess from the passengers of the previous flight.
Lufthansa cleans it's cabins on every turn. This alone makes it impossible to achieve a 15 minute turn, and a 25 minute turn is only possible if both flights fly with a very low load factor. A typical LH short haul turn takes at least 40 minutes, emphasis on the at least.

Also, a 15 minute turn can absolutely only be achieved with walk-on gates. Gates with fingers or remote stands with busses just can't do that, period.
A Ryanair flight that turns unloads and loads through 2 doors, a Lufthansa flight at a finger gate only does through one door, making it absolutely impossible to achieve a time even close to that of Ryanair.

As I said, I eyewitnessed it, and I don't think my eyes lie to me... anyhow, I do agree that it is by far not the rule. Most certainly the previous leg had been delayed by a couple of minutes, as to why they needed to speed up the TAT, to not let the rest of the day's schedule fall behind as well.

Also, you seemingly have never been to DUS, where most of LH's planes are boarded at the apron, as to low number of finger-gates at terminal A (only 10). Nearly the whole eastern apron is Lufthansa, which offers 25 (I think) stands for aircraft.

GDN airport, of which I talked as well, doesn't even have such gates... always walk down the stairs, take bus or walk to plane, climb stairs to board the plane. Anyways, LH used (at the day when I flew) both exits, and had us use the rear exit for de-boarding starting with rows 1 and 2, rolling backwards, and while we exited, the first rows were already re-seated with fresh PAX (Stewardess stood between leaving and incoming PAX, to prevent a mix).

One more thing to add about the LFs, LH operates nearly all of their SH traffic at a loss, due to having to provide too much frequency, which leads to low LFs. When I went to Paris last summer for the PAS, I could experience that "live", I had been on a CRJ9 (86 seats) with only 5 other PAX so basically a 7% LF. I doubt they made a profit :P
Since they often have those low LFs, it enables them to cut short on TAT.

cheers,
Jona L.
« Last Edit: April 23, 2012, 01:38:47 AM by Jona L. »

Offline swadeepc

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Re: Delays
« Reply #15 on: April 23, 2012, 03:14:21 AM »
LH can turn their 733 in 15-20 minutes, and 320s in 20-25 minutes... RYR has 15, maximum 20 minutes for their 738s... but this is AWS, not reality ;)

Yes I understand but surely one thing can be done here. It's not like they got to rewrite the whole game I am sure. Maybe turnaround times can depend on, as mentioned above, flight distance or airport size etc.

Anyway hopefully this problem will be addressed some day.

Offline ChuckPerry

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Re: Delays
« Reply #16 on: April 24, 2012, 12:54:01 AM »
Thanks for all the input guys.. I just know I've flown 150 seat pax planes into and out of DIA for years and even at United which is by far not one of the most efficient airlines with the best employee morale, it doesn't take over an hour under normal conditions..

Offline TerryMcKenna

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Re: Delays
« Reply #17 on: April 24, 2012, 02:12:09 PM »
hi guys,
I work at Perth International.
Singapore Airlines turn their A330s around in about 70 mins for their rotations PER-SIN. Air New Zealand 767-300 in 90 minutes for 7hrs back to AKL and most 7378/320s are turned in 45-50 minutes for 5 hr flights back to the east coast. Syd-Mel 738/320s are turned in 35 mins.
The turn around times in AWS are unrealistically long.
I suggest 20% be shaved of all turn around times.
« Last Edit: April 24, 2012, 06:15:35 PM by TerryMcKenna »

 

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