4 ms·

> At the end of the day, if crew A and plane B are in wildly-unexpected places, no amount of computational prowess can correct that reality. I think that’s not

> At the end of the day, if crew A and plane B are in wildly-unexpected places, no amount of computational prowess can correct that reality. I think that’s not wrong, but one of Southwest’s efficiencies is that they only operate one “type” (term of art) of airplane. So theoretically any crew can operate any airplane. So, in theory, it doesn’t matter which crew is at the airport as long as they meet the rest requirements. You could just use the greedy algorithm and assign the first available crew in the queue to the next flight at each airport. And, since you need a crew to get the airplane to the airport, there are usually crews in the same places as airplanes. (But you have to know that an available crew exists at that airport to do this) Where that breaks down a bit (and where you need a smart algorithm or more compute) is that you can end up with crews at an airport, but the crews are all timed out. So while the airplanes are mostly fungible, the crews are mostly not. The complexity is really filling all the planes for the next-n rounds of flights with crews such that none of the crews times out up to your time horizon. But that only works if you know where all the crews and planes are (and how much time each crew has left) Also, keeping a backup crew at each airport isn’t super expensive because crews are only paid for the time they are operating the airplane while the doors are shut.

tialaramex 3y ago
Also people want to go home. The aircraft don't care if they're in one city or another, but the crews do, for regional in particular it's normal to go home, and if you're out of position at the end of the day that's not possible.
- antonjs 3y ago
  And you have staffing contracts negotiated by relatively powerful unions that require some of these things.
kayodelycaon 3y ago
> So theoretically any crew can operate any airplane. This doesn’t actually hold up to reality because 737 variants are not interchangeable. Gauges may be in the same place but have a different appearance. There have been accidents directly caused by differences between variants. (Shutting down the wrong engine because the air conditioning now used bleed air from both engines, not just the right one.) My understanding is difference training is required to certify a pilot for a specific variant.
- selectodude 3y ago
  The 737 is a single type rating. They are interchangeable. That was the whole idea behind Boeing's MCAS system - the 737-MAX didn't fly the same due to the engines being pulled further forward on the wing, so they made a piece of software that made the airplane feel the same as the 737NG.
  - kayodelycaon 3y ago
    You can’t fly an 737-200 for 3 years and then jump into a 737 NG without difference training. You won’t know how to work the flight management systems. They are the same type, so you don’t need to re-qualify for the type. But you need to do training to move between variants of a type. It’s just a lot less training.

tialaramex 3y ago

Also people want to go home. The aircraft don't care if they're in one city or another, but the crews do, for regional in particular it's normal to go home, and if you're out of position at the end of the day that's not possible.

antonjs 3y ago
And you have staffing contracts negotiated by relatively powerful unions that require some of these things.

kayodelycaon 3y ago

> So theoretically any crew can operate any airplane. This doesn’t actually hold up to reality because 737 variants are not interchangeable. Gauges may be in the same place but have a different appearance. There have been accidents directly caused by differences between variants. (Shutting down the wrong engine because the air conditioning now used bleed air from both engines, not just the right one.) My understanding is difference training is required to certify a pilot for a specific variant.

selectodude 3y ago
The 737 is a single type rating. They are interchangeable. That was the whole idea behind Boeing's MCAS system - the 737-MAX didn't fly the same due to the engines being pulled further forward on the wing, so they made a piece of software that made the airplane feel the same as the 737NG.
- kayodelycaon 3y ago
  You can’t fly an 737-200 for 3 years and then jump into a 737 NG without difference training. You won’t know how to work the flight management systems. They are the same type, so you don’t need to re-qualify for the type. But you need to do training to move between variants of a type. It’s just a lot less training.