With Wings As Eagles: Craig P. Steffen's Blog

spins, measures, cuts...paper strips

2007 February 11 08:11

A lot of the pilots that I talk to consider air traffic control an unwelcome intrusion on their flying time. They intellectually understand that airliners need ATC to fly safely, but would just as soon never have to deal with it themselves. Filing flight plans is something that a lot of pilots just don't do because it's not required. So far in my flight training, I have always filed for cross-country's, and I can't see changing that. It's nice to have the thought that someone will come looking for me eventually if I don't show up at my destination.

I think that ATC is kind of a neat idea. I've been studying the communications aspect of ATC for quite some time. However, I was reading Avoiding Common Pilot Errors: An Air Traffic Controller's View and chapter 4 has an interesting discussion of flight progress strips (Wikipedia, howstuffworks, FAA), which are paper strips that controllers use to keep track of information about an aircraft that's on their screen. (They are part informational printout, part note paper, and part legal document. Their use is portrayed, I think fairly authentically, in the movie Pushing Tin.) You can see flight progress strips in use on this page. Note that each strip represents an aircraft in flight. This Isle of Man airport page has an example of how the strips are used to visually indicate where aircraft are located. Luxembourg ATC has a page with lots of photos of progress strips and other related items.

The point the book brings up is that filing a flight plan is how information gets into the air traffic computer system about your flight. If you file a flight plan, controllers in facilities along the way have a computer-printed flight progress strip pre-printed with all your initial information. They only have to note changes to your status or instructions they've given you. If they don't have a printed progress strip, some controller has to tie up a frequency to get the information from you and write it down.

I actually saw progress strips in use when I paid a visit to the Rockford tower in early 2006. The local controller(s) (radio callsign "tower") and ground controller(s) are on the top floor of the tower building with windows on all sides. The approach and departure controllers are on the next floor down, in windowless rooms with big radar displays. I was very amused to observe the hand-off procedure for a departing flight. When the flight was exiting the local controller's area of juristiction, the controller made a radio hand-off, and then dropped the flight progress strip (attached to it's plastic carrier) down a tube which leads to the desk of one of the controllers in the room below. Efficient in use, but crude in implementation.

As far as the book Avoiding Common Pilot Errors: I think it's an interesting read, and I would commend it to anyone who is at all interested in the technical aspects of flying, with the following proviso: It was written in 1989, so a lot of the concepts are conceptually useful, but not specifically. I really wish there was a newer edition.