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IATA delay definition

Fri Sep 15, 2017 9:35 pm

I've searched for a while after the exact definition of an IATA delay, without result, is there any expertise here on that subject? I'm pretty sure the definition is block off at more than 15 minutes past TOBT, am I right? Then how are seconds counted? For a flight with TOBT 14:00:00, is off block at 14:15:00, 14:15:01 and 14:15:59 respectively counted as a delay? Seconds are not normally used, and time is usually rounded down, but I mean technically 14:15:01 is *more* than 15 minutes past 14. This might seem like a minor issue, but delay statistics are certainly important for most airlines, and of course a huge amount of flights every day are concerned by this, meaningly blocks off between 14:15:01 and 14:15:59! Grateful for any thoughts!
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Re: IATA delay definition

Fri Sep 15, 2017 11:56 pm

I can't answer all the delay codes (we have them available to us at work but I never pay much attention to them), but I can say in my 10 years of full time aviation experience I've never once seen a pilot count the seconds.
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Joined: Mon Sep 24, 2001 6:44 am

Re: IATA delay definition

Sat Sep 16, 2017 1:58 am

In the US, the DOT counts a flight late if it departs later than D-0.

So if a flight is supposed to depart at 12:15pm. I need to block out before 12:16. The ACARs reports a departure of 12:15:59pm as 12:15pm.

I never really understood the importance of D-0. As the passengers really care about arriving on time.
I've left late (past D-0) many times but have been able to arrive before the scheduled arrival time.

DOT doesn't count an arrival as late until A+15. If I arrive at A+14, it's considered on time.
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Re: IATA delay definition

Sun Sep 17, 2017 8:28 am

Then what do the departure and arrival time really mean?

For passenger, the effective departure time is when the door closes (i.e. you are no longer allowed to enter) and effective arrival time when the door opens (i.e. you are free to run for the next flight). And that means the gate door - plane door is not sufficient in case of stand arrival.

Even truer times would be the latest time to report on the airport (or take one's place in the queue) and the time when one has got all the luggage and passed the last customs/immigration/security control ( is free to go home).
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Re: IATA delay definition

Sun Sep 17, 2017 12:44 pm

I've seen it labeled a few different ways. Some consider it to be door close, others use brake release, and others use actual pushback time.

Most common is definitely out/off/on/in. (May have mixed up the order) which I think goes by parking brake
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Re: IATA delay definition

Mon Sep 18, 2017 5:29 am

I've only ever seen four times used. Land. Inblock (STA). Offblock (STD). Airborne. Probs got other names in different airports.

Then what do the departure and arrival time really mean?

As far as I was concerned STD and STA are akin to Scheduled Offblock Time and Scheduled Inblock Time.

We are technically supposed to record a delay even if it pushes 1 minute over it's minimum turn time. We, however, use our common sense and have a 3 minute window of grace.

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