With respects to the turn-around time, what's better - having an over-cautious turnaround where it displays a chance of delay at ~1%, or a tight turn-around (where it says 25%)
I ask as whilst I regularly see some delays, this is normally in the region of 15-30 minutes, which is less than the shortest turn-around time. Would it be better to just fly to tight turnarounds and risk the occasional plane being cancelled, or give them plenty of time to turn around, at the risk of having idle planes most of the time.
The 1% is already too much = waste of time...
Quote from: sami on February 02, 2013, 05:35:31 PM
The 1% is already too much = waste of time...
That's good to know... I always scheduled turnarounds with the shortest time that displayed ~1%... I'll go for higher percentages!
Personally I still do the 1% unless going up a little means I can squeez another flight in.
I always use ~1%. We're only talking about 10 minutes here round trip. When you factor in weather (which can be brutal), maintenance, etc. there are plenty of ways to spike you're delays/cancellations with things you can't control, so why not take do what you can to avoid the things that you can control?
At 4 legs/day, going 5 minutes shorter = 40 minutes extra time. At 4 legs/day, your average round trip is 6 hours. So for every 9 planes, you'll get 1 extra route in. So you're increasing your profit by 1/36 = 2.8%. If 5 minutes shorter turns means your cancellations go up by more than 2.8% on those 9 planes, you're losing out. And that assumes you're actually making use of those short turns by scheduling completely efficiently, rather than using short turns all day, and then having a 3 hour gap between the last flight of the day and the first flight of the next day.
I always use the shortest possible 1% turns, except for those planes where 5 minutes short only makes it 1.4% (which is 40 minute & 80 minute defaults, a320, b737, MD80/90, a330, etc). But I'll use an occasional shorter (or longer) turn to fit a route in. I'll also use shorter turns if it's a temporary fleet, so I can switch schedules between two plane types, like 734 and 738. Set up schedules on 738 timings, and use short turns on the 734s to make them fit the same departure times. Or use long turns on a 707, so the schedule switches seamlessly to 757s when they start arriving in DOTM (I *should* have done this, but didn't. When my 757s start arriving, replacing the 707s will involve heaps of fiddling. :laugh:)
Short turns are fine, if they're giving you some other benefit. But for the OP in Eurochallenge, your 50 minute turns on #001 & #003 don't actually give you any benefit, all they do is increase your delays on those flights, and the 30 minutes you save just gets wasted later in the day, when you have a 105 minute turn between #008 & #009.
On a similar note: is it ever possible to reduce flight delays?
I have spent a lot of time revising schedules to lower late flight times. When I fix one, another one appears!
Is it just a programming fact that (given delays for winter, etc), some of an airline's flights are going to be late - no matter how much time is left in the schedule for turn around times?
Yes. You'll never get 0% delays for any reasonably sized airline.
I always aim for ~10% chance of delay and do just fine.
I always do 1% and will typically have on time in the high 80's or low 90's. It also helps when you are creating your schedule. If you have your final flight arriving too late, have limited slot opportunities, or maybe you can't squeeze maintenance in or another flight, you can cut your turn times on a previous route (or routes), without hurting on-time.
Thanks for all your input, certainly helps me understand a little better :)
Anything below 8% is my advise