Delay/cancellation because of too short turn arounds

[Ilyushin]

How come my flights get delayed quite often while the chance for delay/cancellation is 1%? I always give it enough time so the chance is 1%. It seems like this number isn't correct or something, because far more flights than 1 in 100 get delayed/cancelled.

What am I doing wrong?

[ucfknightryan]

How come my flights get delayed quite often while the chance for delay/cancellation is 1%? I always give it enough time so the chance is 1%. It seems like this number isn't correct or something, because far more flights than 1 in 100 get delayed/cancelled.

What am I doing wrong?

If you check the flight delays report, in the routes section, you can see a breakdown on why your flights are delayed.  Currently one of my airlines has over 6% of its total flights being delayed by weather (which is over half of total delays), another 3% or so by airport and route traffic restrictions (airport is just really busy and that causes delays), and maybe 2% from too tight of scheduling (which probably means I screwed up my math somewhere when spacing out flights).

Why are your flights being delayed?

[Ilyushin]

45% scheduling, 6% tech probs, 10% traffic restriction, 36% weather.
All my flights have 1% chance to be delayed.

Very odd.

[twistedraisin]

Make sure you're accounting for turn-around time in your bookends between scheduled routes. In other words if you're flying an f100 that departs at 5am and returns to the home airport at noon, make sure the next flight isn't scheduled until 1pm (~1%, 60 min turn)

[Ilyushin]

Aha, that should be it. My flights depart right after they've arrived. Thanks for your help.

edit: There's always a 30 minute wait before departing again (or does that depend on the type? Type is ATP). Anyway, does that count to the turn-around time? In other words, if I make it 50 minutes, so depart 20 minutes later than it can, does it decrease the chance to 1%? (On ATP, 1% chance for delay is 50 mins)

[twistedraisin]

Yes, that should be correct - it's the same calculation for between routes as it is for the turn-time during the route, so what I do is simply find what the estimated turn time is to get to ~1% during the route, and add it to the arrival time of the plane back at its base, and that will tell me the next time it can depart with a ~1% chance of delay.

Example: on on f100: leave base at 0500, arrive destination at 0800, 60 minute turn for ~1% chance of delay, leave destination at 0900, arrive at base at 1130, 60 minute turn for ~1% chance of delay, next available departure time is 1230 soonest.

[takasito]

If you can give can give extra 10mins after each segments, flight cancellation due to too short turn arounds will drop dramatically.