On Time Percentage vs Utilization?

[Karl]

Assuming decent market demand, in theory what is better for an airline in the long run:  excellent on time performance or high aircraft utilization = flights 24 hours per day?

I have widely spaced my flights to achieve few delays.  Plus, except for some red eyes where they make sense, I have very few flights operating all night.  This seems like a sensible way to run an airline that passengers want to fly.

I have noticed, however, that some successful airlines have high aircraft utilization and that flights arrive and depart airports at all hours of the day and night.

Am I setting myself up for a great on-time rate (which has any influence on anything?), but lower profits?

[Sanabas]

Am I setting myself up for a great on-time rate (which has any influence on anything?), but lower profits?

Yes.

As long as your punctuality is above ~90% or so, and cancellations are only ~2% or less, you've got no problems. Numbers will be better in summer, worse in winter, as airport weather conditions force delays/cancellations. Drop your percentages below that, and you'll be hurting your CI somewhat, and cancelled flights also earn no money.

Long turnaround times during the day are sometimes necessary because of slot restrictions, or because your plane's daily schedule has 22 hours of routes instead of 24, or whatever. But they do mean less profit overall.

Middle of the night flights won't have great LFs, won't have great profits. But they will (usually) make more money than if you simply leave the plane sitting on the tarmac. Ideally, every plane would spend 24 hours/day flying, and never take off/land between 2300-0500 local time. But that's very hard/impossible to do for shorthaul routes & smaller planes, and is heavily airport dependent as well. So you may as well fly overnight. It also means you've got more flexibility in your scheduling. Say you've got a route that is 3 hours each way, with a 1 hour turn time. It can handle 3+ flights/day. If you won't ever fly middle of the night stuff, then you're restricted to 0500-1555 as your takeoff time. Evening slots at your airport will hardly get used. But if you depart at 1855, then the outbound leg is perfectly fine, and only the return leg is a night flight. Then the plane can go to the same place at 0255, and this time the outbound leg is a night flight, and the return leg is a perfectly normal early morning flight. That sort of scheduling can help a lot in a busy, slot restricted airport, when all the 05xx-07xx slots have disappeared.

[LemonButt]

You should always be scheduling with turnaround that have ~1% chance of delay.  You only earn revenue when the aircraft is flying, so of course 24 hours is best, but it never justifies delays.  I'm not sure what you're asking here because it sounds like you want to know whether it's better to have turnarounds with 5%+ chance of delays to squeeze in an extra flight versus having ~1% delays.  The truth is, if you are scheduling turnarounds for anything higher than ~1% delays, you're only saving a few minutes and you won't be able to squeeze in an extra flight anyways.  You can fly 24 hours/day by simply flying east at night to timezones that are ahead of your base.  The 2300-500 hours are the slow periods and you can take off from the west coast of the US to the east coast at 2300 and turnaround to go back at 600 with prime departure times.

[Sami]

You should always be scheduling with turnaround that have ~1% chance of delay.

Wrong,wrong,wrong. May I re-phrase: "You should be always scheduling .... ~1% chance of delay - if you wish to plan for inefficient fleet usage".

You most certainly do not need to extend the turnarounds to such long times. But true, if you push the extra 10 minutes out of every turnaround (let's say 6 of them during a day), you cannot fit an extra full flight - but at least I have been using even 50 min turns with B727 with no problems on some tight schedules.

[Sanabas]

You should always be scheduling with turnaround that have ~1% chance of delay.  You only earn revenue when the aircraft is flying, so of course 24 hours is best, but it never justifies delays.  I'm not sure what you're asking here because it sounds like you want to know whether it's better to have turnarounds with 5%+ chance of delays to squeeze in an extra flight versus having ~1% delays.  The truth is, if you are scheduling turnarounds for anything higher than ~1% delays, you're only saving a few minutes and you won't be able to squeeze in an extra flight anyways.  You can fly 24 hours/day by simply flying east at night to timezones that are ahead of your base.  The 2300-500 hours are the slow periods and you can take off from the west coast of the US to the east coast at 2300 and turnaround to go back at 600 with prime departure times.

What if you're on the east coast of the USA? Or SE Asia, Japn, eastern Australia, even places like Moscow or Istanbul? Not too many destinations that are short enough for 100-150 seat planes, and long enough for a redeye flight from those places.

As for getting an extra flight by squeezing 5 or 10 minutes somewhere, you absolutely can. Of course, when you're just starting your airline, you'll have a huge number of choices, so the extra 5 minutes won't make much difference. But once you start to fill up your SH routes, you have many less options. When you have 40 planes all flying 4-5 routes each that are up to 7 hours long, you can start to run low. So instead, I pick 5 routes that add to 24:10, and have one turn be 10 minutes short. It makes no difference to the first plane, it will have 5 routes either way. But when there are 40 planes, 5 routes each, 5 minutes saved on each one in each direction, that adds  up to 2000 minutes, over 33 hours extra, which means 6 more flights across those 40 planes.

[Sranan]

so....if flights are scheduled between 0000 and 0500, the lf willnot be high, but you still make some profit??

but, i thought this will hurt route image/company image??

if i understand sami's statement, then planning for only ~1% tat is hurting rather than helping fleet utilization.

[Sanabas]

so....if flights are scheduled between 0000 and 0500, the lf willnot be high, but you still make some profit??

Most of the time, yes.

but, i thought this will hurt route image/company image??

Not at all. Constant delays/cancellations hurt CI. As long as you fly the route regularly, RI will head to 100 and stay there. People prefer not to fly in the middle of the night, but they're not going to dislike your whole airline just because you offer middle of the night flights.

if i understand sami's statement, then planning for only ~1% tat is hurting rather than helping fleet utilization.

If you rigidly stick to 1%, always, then you probably won't be as efficient as you can be. If you constantly use 20%+ delay chance turns, your fleet utilisation will probably be very good, but the excessive delays may cause problems. If you mostly use 1%, but sometimes go shorter to fit a route in, you can probably have good fleet utilisation without too many delays. If you always use ~5%, and occasionally go shorter, you might be even more efficient, and the higher profits from that might offset the lower profits from cancellations. Depends how you want to run things, and there isn't a definitively right answer.

[LemonButt]

Wrong,wrong,wrong. May I re-phrase: "You should be always scheduling .... ~1% chance of delay - if you wish to plan for inefficient fleet usage".

You most certainly do not need to extend the turnarounds to such long times. But true, if you push the extra 10 minutes out of every turnaround (let's say 6 of them during a day), you cannot fit an extra full flight - but at least I have been using even 50 min turns with B727 with no problems on some tight schedules.

How is this wrong?  Yes, you don't HAVE to schedule every single flight for ~1% delay turnaround, but you should make it a habit of doing so.  My airline in MT6 has 99% of the routes with ~1% delay turnarounds and my punctuality is 93% due to technical issues, route restrictions, etc.  My average fleet age is 2.0 years with my oldest aircraft being 4.6 years old.  If someone has an older fleet, the delays will be much worse.  I also have a 16 hour fleet utilization using this scheme with less than 20% of my aircraft being used for international long haul over 2000nm.  How is this inefficient? 

On top of this, if flight delays get bad enough your CI will go down, which is essentially marketing dollars thrown out the window.  If your turnarounds are too tight, cancellations go up as well which not only hurts your CI, but doesn't produce revenue.  Even with a new fleet and ~1% turnarounds I still have 1.7% cancellations, which is pushing it.

Unless I'm some whiz kid, I don't see anything wrong with my statement of always having ~1% delay turnarounds as a rule of thumb.  Yes--if your schedule gets tight you can shorten the turnaround slightly, but it's much better to shorten a long turnaround to make a route happen versus shortening a short turnaround and hurting CI and losing revenue to cancellations.  Proper planning means you should have to use shorter turnaround less than 1% of the time in my book.  Even doing this I have been docked CI points for excessive delays due to variance.

Even if you are shaving 5 minutes off each turnaround time and you're flying 5 short hops, this amounts to only 50 minutes, which isn't enough time to fly anywhere and back.  Again, if you're doing proper planning you'll never run into an issue where you need 50 extra minutes to fill a schedule.

[Karl]

My airline is running a 95.9% on time rate for the past week with an average delay of 1 minute.  I am proud of this figure.
When building a schedule, I always use the 1% delay statistic, and if I can't fit another turn in the schedule, I usually widen the turn time.

I started this thread because I was wondering if such a high reliability rate really earns me anything in this program- like more passengers, or in reality it would be better to squeeze in as many flights as I can - even being less worried about on time performance.

From the responses, it seems that it is wise to stick with turn times that do not cause delays.

[Sanabas]

Even if you are shaving 5 minutes off each turnaround time and you're flying 5 short hops, this amounts to only 50 minutes, which isn't enough time to fly anywhere and back.

While this is correct, the idea that always using turnarounds that are 5 minutes short won't enable you to fly more routes is wrong. 50 minutes per plane equals 5 hours for 6 planes, which is more than enough time to fly an extra route. There IS a benefit in terms of the number of routes you can fly from consistently using short turnarounds. Whether that benefit outweighs the problems from extra delays is a judgement call for owners to make. Depends on the plane, too. A plane with 45 minute turns for 1% is 2.8% at 40 minutes. 1% 50 minute turns become 8% 45 minute turns. 1% 70 minute turns become 1.4% 65 minute turns. Personally, I'll usually use 1% turns, except for planes like the a320/MD90 that have 40 minute minimum, 70 minute 1%. For them, I'll usually use 65 minute, 1.4%.

Again, if you're doing proper planning you'll never run into an issue where you need 50 extra minutes to fill a schedule.

Again, this is wrong. I do proper planning. I've now filled enough of my <600 nm routes that I frequently run into an issue where I can't find 4 or 5 routes that add to exactly 24:00. The best I can do is often 23:50 or 24:10. Give me 30 more Saabs (and the slots to use them  ), and I'll be lucky if I can get it within 30 minutes of 24:00 if I stick to 4 legs/day. The most recent plane I scheduled was 24:20, so the overnight flight has a minimum length turn. More to the point, if I do proper planning and make ALL my routes 10 minutes shorter for the round trip, then I get slightly longer routes into each 24 hour block, and more routes overall into a group of 20 24 hour blocks.

If we both use ATRs, and both schedule perfectly, yours will spend 18 or 16:30 hours/day airborne, mine will spend 18:40 or 17:20 in the air. For every 20 planes you schedule, I'll fly the exact same routes with 19. I'll save ~250k/month in lease costs, plus some more savings on maintenance, staff, etc. THAT is the benefit of consistently using short turns. Of course, I should have more cancellations, which is the downside to consistent short turns. At ~10k/per route profit, 25 extra cancellations per month on our ~2500 monthly flights is the breakeven point. That's only 1%, so with my 2.8% turns to your 1%, my extra cancellations should outweigh your extra plane costs. I hadn't run those numbers before, that was interesting.

*edit*And of course, it depends if 2.8% chance of delay equals 2.8% chance of cancellation. In MT, my current cancellations from scheduling are 0.88% (83/9387). In JA, it's only 0.6% (61/10009). Both airlines have mostly 1% delays, with quite a few shorter turns, and the occasional longer. So if 2.8% delay chance works out to 1.5% cancellation chance in practice, then short turns may actually be slightly better.*/edit*

So yeah, seems reasonable to aim for 1% turns as much as possible. But there's no reason not to use the occasional short turn in order to jam slightly long routes into a 24 hour block.