Tuesday, April 28, 2009

ADS-B Here



There’s an interesting article in Aviation Week about ADS-B. In essence, it’s being installed as we speak. You can read it for yourself (2 pages) but let me point out a few “gotcha”s.

”While ADS-B has been employed for air traffic control before, the FAA will break new ground by using it to provide standard 3-mi. aircraft separation in terminal airspace, says Vincent Capezzuto, the agency's program head. “

Notice that 3 miles is already the standard separation in “terminal” airspace -- as in “not enroute” airspace. Standard separation in enroute airspace is 5 miles. In other words, nobody is running airplanes any closer together. This is good. But it is not what the public has been promised.

”The Houston deployment is unique: Some of the ground stations will be installed on offshore oil platforms, giving the FAA radar-like surveillance over the Gulf of Mexico for the first time.“

How to install “ground equipment” in the middle of the ocean has plagued the FAA for years. I won’t go into all the details -- I just want to point out that the “space-based” system is dependent on oil rigs. Oil rigs that are not in a fixed location and are owned by somebody else. Say, don’t they abandon those things during a hurricane ?

”ITT has already begun installing the more limited "essential service" ADS-B infrastructure - providing only cockpit information - even as development of the critical-service version was underway.“

This, in my opinion, is going to provide one of the most significant human factors challenges for NextGen. People always lose their minds when they see new technology (Look ! Something shiny !) and never think about how people will misuse the technology. For instance, think about a controller calling traffic to another pilot when they can “see” each other on ADS-B.

Controller: N12345, traffic two o’clock, 7 miles, a Cessna Citation. You’ll be number two behind that traffic, report the traffic in sight.

N12345: Roger, Approach, we’ve got ADS-B, we see November one two three charlie charlie.

N123CC: November one two three charlie charlie, did you call us Approach ?

Now, if you’re thinking call sign confusion, that is good. But does N12345 have N123CC “in sight” ? And if you think pilots will instinctively be able to separate themselves using a radar-scope-like device (an ADS-B display in the cockpit), you’ve got another thing coming. Every pilot and controller in the country will have to be trained on new phraseology. Everybody knows, don’t get me started on phraseology.

”The ADS-B contract represents a new approach for the FAA. The decision was made early to have an outside company own the infrastructure, and the FAA would contract for service provision. This would shift a lot of the program risk from the FAA to the contractor.“

I think this is going to be a huge can of worms. This stuff isn’t like a personal computer that you will throw away after three or four years. This is infrastructure upon which your national air transportation system will depend for years and years. 20 years. Maybe even 40. Every system that I can think of in the FAA has been used far longer than the original estimate. Radars, radar scopes, printers, radios -- everything. That’s a long time to lease equipment. And it doesn’t even begin to address the concerns about maintenance and certification.

Don Brown
April 28, 2009

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