Aircraft route planning
 

I found myself playing around on the United app by clicking "where is this aircraft coming from?" Over and over to get an idea of where my aircraft had been in the last few days. It's amazing how little time they spend on the ground and I started to wonder whose job it is to plan the routes that an aircraft will fly in order to make it as profitable as possible. I'm sure there is a science to it but it seemed almost haphazard - my plane was in Hawaii one day and doing shorter Midwestern hops the next. So which person/team is responsible for determining where the planes are flying on a daily basis?

Naming will vary by airline, but operations research is the discipline required. The staff will include a bunch of well paid and rather smart engineers and mathematicians who have specialised in optimization problems.

They also have to align crews with the aircraft, and that in itself is a complex problem when you take into account crew seniority, legal flight/rest hours, type certification of pilots etc.

Link to an old paper on Crew Scheduling at Air New Zealand

For United, I believe the network planning and scheduling department is responsible for the planning of the routes. These routes are planned seasons in advance. I don't think that final aircraft assignments are made until a few days before the flight. Short term day to day flight planning is in the hands of the dispatcher, I believe.


Here is a video of the flight scheduler for WN (not very informative) as well as a video of a dispatcher:

Inside Southwest Airlines: Schedule Planning

Inside Southwest Airlines: Flight Planning and Dispatch

Youtube user, Jetsetter, has a multi-part self made video on the United Netowrk Operations Center: https://www.youtube.com/results?sear...+noc+jetsetter


Some more in-depth resources:

Integrated Airline Operations: Schedule Design, Fleet Assignment, Aircraft Routing, and Crew Scheduling

Or search Google for "Airline Planning and Schedule Development". First link should be a PDF ([PDF]Airline Planning and Schedule Development - Springer). I chose not to link to it, due to the fact that it does not open in the browser, but rather downloads the PDF.

...and THEN add in factors such as scheduled maintenance and unscheduled maintenance. Only certain locations are equipped to perform certain maintenance. So, let's say an ultra-sound inspection of a wing spar has to be performed every 500 flight hours, and only LAX and MIA are equipped to perform that inspection, the scheduler needs to ensure that every 500 flight hours that plane's last flight of the day ends at LAX or MIA. But let's not forget, there's dozens of other schedulers who are also trying to get their planes inspected...and each base can only accomplish 2 inspections per night. Uh-oh...the ultra-sound equipment in MIA is due for it's annual calibration; it will be down for 2 days until the guy who's certified to do the calibration gets back from vacation..........

And that's just one inspection out of thousands.

It's a breath-takingly complex affair.

The applied math discipline behind it is called Operations Research (OR). The field was made popular by the US army planners back in WW2. Now it is used by nearly everyone from the airlines, to the big banks, and even Waffle House (they are actually one of the best in the OR business). The discipline is mostly about modeling decisions problems that require minimization of certain quantities such as time, delays, costs, etc as standard classes of mathematical optimization problems. Preferably linear or convex optimization problems since they are tractable up to large sizes. The main difficulties lies in making useful models and sometimes solving an intractable optimization problem. The models are also usually stochastic since most of the time the available data only gives you probabilities not certainties.

One of the biggest buzzword in current research in airlines OR is:

Collaborative Decision Making (CDM) - essentially all the airlines in an airport combining their operations to minimize overall delays and congestion in the airport. The eurocontrol's website on CDM is http://www.euro-cdm.org/ The FAA's is http://cdm.fly.faa.gov/