I am surprised and very interested in the replies to my thread on crew logistics to maintenance bases. I perhaps should ask this in that thread but this is a bit different. So forgive me if I err.

Some number of years ago I was on a flight from IND to DFW that got seriously delayed because of a MX issue. We pax were deboarded and many were booked on other flights during the subsequent hours but as luck had it I remained booked on the original flight which eventually departed five or six hours later.

As I was exiting I asked the pilots, “do you get paid during the wait?” And they said no.

Which leads to the question. If the pilots are not on duty but five or six hours passes (time from when they woke up doesn’t change) are they still legal for the normal hours? To be clear, they flew us to DFW but for all I know were scheduled for some other flights that day.

Specifically what prompts this question is I saw AA50 from DFW to LHR this evening made it as far as Pine Bluff, Arkansas, then turned around and came back to DFW. So one presumes 2-3 hours of duty time were consumed. Now some time, maybe an hour or two, will be required to get the flight back in the air.

Will a new crew be required?

And on Trans-Pac flights, where there is relief crew, does the situation change?

I appreciate your forbearance on what must be very basic issues but I find it most interesting.

European pilot here, so answers will differ a bit from how the US does things:

QF7 wrote:

As I was exiting I asked the pilots, “do you get paid during the wait?” And they said no.

Hourly pay/flight pay isn't really a thing here. Most typical is a fixed monthly salary and daily per diems. We don't get paid extra for waiting, but if the delay means we slip just across midnight, that's an extra days per diems.

QF7 wrote:

Which leads to the question. If the pilots are not on duty but five or six hours passes (time from when they woke up doesn’t change) are they still legal for the normal hours? To be clear, they flew us to DFW but for all I know were scheduled for some other flights that day.

It definitely counts as duty hours here. When exactly duty time begins depends on the airline and country, but most sensible airlines would say duty time starts around 45-60 minutes before scheduled time of departure, while some of the shitty ones push it to as little as 15 minutes before. They won't be getting away with crews loitering around in an aircraft for several hours however.
There are ways to get around the flight duty limitations. The airline can offer to send the crew back to the hotel for some more rest, and in some cases extend the FDP by a period. The airline doesn't win back the full FDP and has to extend the subsequent rest period, but if the flight isn't too long, it is possible to get it off with a bit of planning.

One time I was caught up in an ATC strike lasting 6 hours. We had rushed to try to get off the ground just before it hit, but we just missed the cutoff point. The airline offered to take us back to the hotel for rest and return 5 hours later under the split-duty rules, or alternatively refuse it and leave it to another crew. We opted for the split duty and got going later that day. We were then unable to fly the next day because of the mandatory rest rules, so another crew was brought in to fly our schedule the next day.

FWIW, crew scheduling is a science in itself.

In the US it depends on the pilot contract. So it differes from airline to airline

in general all airlines follow FAR part 117 flight time duty time rules.

Rules change between unaugmented (2 pilots) and augmented (more than 2 pilots) crews

FDP governs how long crews can stay on duty. Crews can be put on split duty but my airline’s pilot contract does not allow split duty.

My airlines pilot contract also puts additional limits on FDP if the FDP occurs between 0100 and 0400 of the pilots domicile time.

For delays longer than 5 hours the contract requires a hotel room but we stay on duty and the clock continues to run on our FDP. Sounds great in theory but in practice the delay is just an hour. An hour later the delay is now just another hour longer. Then another 30 minutes longer an hour later. Before long we’ve had a 5 hour delay…

In addition to FDP limits within a 168hr period and 678 hr periods, there are flight time limits for a duty period, 678 hr period and a 365 day period.

FDP limits and flight time limits depend on what time the crew comes reports on duty and how many segments (legs) they are scheduled to operate.

Normally crews are paired. So it’s not too hard but if the pilots are not, issues could arise. For example a west coast pilot paired with an east coast pilot in an unaugmented crew. When everything is running on time everything is good. But if an irregularity occurs i.e. delayed for whatever reason. The west coast pilot could be legal to continue to operate but the east coast pilot becomes illegal and “times out.”

There are also trip and duty rigs that govern pay. Fir example one 4-day trip I was on turned into a 7-day trip that was interrupted due to weather. I was scheduled to fly 6 segments and 18 hours during the 4-day trip and credit 20 hrs of pay. But due to the weather we only flew 3 segments and 10 hours but got paid 36 hours due to the trip and duty rigs in the pilot contract.

The crucial point is that pilot pay hours are not the same same thing as duty limits. The former is a contractual pay thing. The latter is a legal limit thing.

For example, if we're delayed before push we aren't off blocks yet so it doesn't count as time for flight pay. However, it does count as time towards duty limits. You can run out of duty limits without a single minute of flight pay, for example if you're crewing a 14 hour flight but you're delayed at the gate 6 hours.

For many US Airlines there is Duty rig pay formula as well as a Flight pay formula in which case the crew would get paid based on whichever one was greater. Most airlines will create schedules where Duty rig doesn't come into play but when there are long delays it is possible for a crew to see an increase in pay based on Duty rigs.

QF7 wrote:

”If the pilots are not on duty but five or six hours passes (time from when they woke up doesn’t change) are they still legal for the normal hours? To be clear, they flew us to DFW but for all I know were scheduled for some other flights that day.

I saw AA50 from DFW to LHR this evening made it as far as Pine Bluff, Arkansas, then turned around and came back to DFW. So one presumes 2-3 hours of duty time were consumed. Now some time, maybe an hour or two, will be required to get the flight back in the air.

Will a new crew be required?

And on Trans-Pac flights, where there is relief crew, does the situation change?

QF7, the answers to your questions can be somewhat complicated, and they are also variable depending on the pilot contract, and in the United States, governed by FAR 117.

To address your first question regarding the flight from IND to DFW . . .

At my operator, for pilots, our duty day begins one hour prior to scheduled departure (based upon arriving at the airport an hour before the flight) and ends 30 minutes after block-in following the last flight of the day. Under normal conditions, we are limited to a 12 hour duty day, but it can be extended to 14 hours under certain conditions of irregular operations and concurrence by the crew member. Somewhat different, our flight duty period is limited to 8 hours in a 24 hour period and this is based on block-to-block times. This is the time for which we are actually paid.

As you can tell from the response above from Woodreau (Reply # 3), it can get complicated depending on many variables. Crew scheduling has very sophisticated programs that track all this for crews and the times are updated after every flight. At one time, quite a few years ago, most pilots could track it themselves with a pencil and a simple calculator. Not so much anymore. At least not for me . It seems like much of it changed--and got more complex--over a period of years--following the accident of Colgan Air Flight 3407 at Buffalo in 2009. There were quite a few changes made to FAR 117.

Regarding your question about whether your crew (IND-DFW) was scheduled for additional flights after arriving DFW, you stated the delay was five or six hours. Crew scheduling tracks delays like this. If the crew did indeed have additional flights scheduled after DFW, in order to maintain integrity of the schedule, crew scheduling would have probably called out a Reserve crew to work the subsequent flight, or else issued "re-routes" to other crews transiting through DFW to minimize delays. In some cases, however, and depending on the airline, any subsequent flight those pilots were scheduled to work may just have to be delayed or cancelled. In the event of re-routes, scheduling attempts to put the crew back on their original trip at some point, if possible.

Finally, concerning your question about AA50 DFW-LHR, the answer is, again, it depends. The crew would have been augmented, so it is POSSIBLE the original crew could have worked the flight, but my guess is that crew scheduling would have called out a Reserve crew to mitigate any further delays that could occur in getting a new aircraft or repairing the original aircraft (assuming the return to DFW was based on a mechanical issue).

I hope this helps and makes some sense. Sorry, cannot answer your question about Trans-Pac operations.

e38

Thanks for the interesting and informative replies, and again for those in the earlier thread. For an industry outsider it is enlightening to learn of some of the decision parameters affecting scheduling.

Many years ago in college in an introductory computer programming course I wrote a program for fire department dispatching. If fire station one was already responded to a fire and a second fire was reported would it be fire station two or fire station three that would respond? Those kind of scenarios. It was fascinating how quickly it became very complicated as additional incidents were introduced.

In a large airline with hundreds of daily ops I can only imagine the complexities but I find it very intriguing. I bet I would have enjoyed being a dispatcher. Again, thanks for providing a glimmer of insight.