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Interview with Robert Everett - 12/8/00

Summary: ATCAC came up with the idea for DABS. ATCAC talked to all parties involved: GA, AOPA, LL, MITRE, commercial airlines, FAA, etc. to assess needs. Crashes invoke action and reform. The problem is ATC is slow to change.

  • We asked him about ATCAC. He said, he was asked to serve on ATCAC. He remembers that it was a good group and everyone worked hard, tried to look at the whole business, came up with the DABS idea. There were people who felt the whole thing could be done with satellites but the rest of us felt that it was premature at the time. The chairman - Ben Alexander - asked him to serve, he remembers him being a very good guy.

  • Everyone understood that the ATC system had a lot of weaknesses. They basically had been charged with a fresh piece of paper to look at air traffic control, where it was going, etc (missed half this quote). "ATC had always been quite safe, but not always efficient". Every once in a while there were safety problems. You can't really separate efficiency from safety - "it has to be safe but on top of that it has to be efficient or it won't work".

  • [asked about satellites:] it was pretty clear that you could use satellites for certain communications and for navigation but it was premature. After all there are still problems/is still attention?? (couldn't hear) with much heavier use of satellites in ATC today, lots of attention on using GPS in ATC, and will continue to be in the future. There were no serious considerations for using satellites, it was just one of the things that were brought up at the time. At that time. ATC was mainly radars and beacon systems. Ground had to know where airplanes were, planes had to know where they were... needed location, communications, and monitoring, and "DABS seemed like a good idea because it combined a more accurate beacon system with a communications system". He said the fundamental thing was to measure where the aircraft was and to communicate with them, which were fundamental issues for ATC, and DABS did that.

  • he said the existing system allowed people on the ground to be able to measure where airplanes were in 3D space, where they wre going, how fast, and use this information to keep them apart. It wasn't all that accurate, which led to very wide spacings between airplanes to make up for inaccuracies in the beacon system. What was inadequate? the beam width of the ground system of radars was wide, not very accurate, would like to be able to do better. Like to have more communications with the airplane, want system to be better built, easier to make work together.

  • "fundamentally you have a couple reasons to want to reduce workload...as density increases, one way to handle it is to break the space into smaller pieces. However, handoff problems get worse". need cross-capacity to improve efficiency of the system. what you would really like would be just to give a course at the airport in advance, the airplane follows the course, people do what they're suposed to do, and there would be no trouble. but people drift and it doesn't work that way.

  • He said that it was a collaborative effort. They had people from ATC, airlines, equipment companies, etc coming in and got their ideas, their thinking, what they were planning on doing. They also visited organizations.

  • Therefore they talked to controllers, the FAA (including people doing research and development for future work at the FAA), MITRE, Lincoln Labs, the ATC Association, pilots union, and not just commercial work but also GA, AOPA, small airplanes, airport operators and owners, etc. There was a tremendous group of people involved and we have to talk to each about what they were thinking, not just to find out what they have to say but also so they know their thoughts are taken into account in the committee's decisions and that we're not making completely unbased decisions. He says this is usually what happens with a committee like this.

  • I asked him if he remembered who started ATCAC and why. He said he thinks it was asked for by the FAA but he doesn't remember. He says what usually happened was there'd be an air-to-air collisions He said the situation is kind of like with automobiles where what you're afraid of is that one crazy driver who'll crash into you, and that most people think you'd be just fine if there were no other drivers around.

  • People flying in airplanes worry about the same thing, though the emotional impact of being flown into by another airplane is much larger. Somehow you just don't feel like that should happen, and you know when it does that means pretty much that everyone dies, there's no way around that. So every once in a while, there'd be a collision - he said that there was one in Grand Canyon (this was mentioned in the ATCAC report) where there were a lot of planes flying around with people looking out the windows, and two planes crashed, killing a lot of people. This immediately caused a big uproar, politican, and in the papers, with people running around talking about doing something, how something had to be done.

  • I asked him if the drifting attention of the public/politicians is one of the reasons for the slow rate of doing things in ATC. He said. There are several major reasons for slow adoption: The system is blamed for accidents, and therefore is run conservatively. If you want to try new things, or make major changes, to prove efficiency there are a lot of questions. The FAA people in charge are also conservative because they are held responsible. Therefore any changes are slow to take effect. It takes a long time for the government to do anything, and it takes time to build a complex ATC system. Therefore it takes a long time to get anything done. You can only speed up the process by keeping continual pressure on it. Have a stream of accidents, but of course nobody wants that. He said you could look at it like a signal where each pulse is an accident, but it decays in the time in between pulses.

  • He then compared air traffic control to the air force, saying that Air Traffic Control takes longer than the Air Force because they're not as concerned with safety. In the Air Force, the pilots are getting shot at and they're more concerned with the problem of getting shot at than the problem of safety. Also, while the Air Force is practicing for much of the time, they're fighting wars for only a small fraction of the time. They can start out with an entirely new system, like Sage, deploy it, try it out, correct it, and the only pressure is that they hope the enemy wont' attack while they're still tweaking the system, which it normally doesn't. In Air Traffic Control, the system is up 24 hours, 7 days a week, while they're trying to fix and change it, which makes it harder.



  • The Story of Mode S: An Air Traffic Control Data Link Technology last modified: 12.06.2000