Re: Avionic Proximity Warning

[CONDIC@PSAVAX.PWFL.COM]

From: Marin David Condic, 407.796.8997, M/S 731-93
Subject: Re:Avionic Proximity Warning
Original_To:  PROFS%"SMTP@PWAGPDB"
Original_cc:  CONDIC



Bob Wells #402 <wel@EUROCONTROL.DE> writes:
>
>What is the name of this piece of equipment that tells a pilot the
>evasive action he should take to avoid a possible collision with
>another detected plane? Such advice is given locally, and is totally
>independent of any ATC instruction (making it a bit dangerous IMHO).
>
I worked on programming such a radio device called TCAS which (if
the two remaining brain cells are still functioning after the New
Year's parties...) stood for Traffic Collision Avoidance System.
Our implementation was for a radio called ICNIA and was written
in JOVIAL. (Other implementations could have - and probably were
done in just about any other language. It's a radio protocol. Not
a specific piece of hardware.)

Basically, it worked by having two planes trade off
positional information and if they agreed that they were in
immanent danger of collision (something under a mile, if memory
serves) they'd take a vote on which direction each plane should
move in.

Its independence from ATC instruction wasn't dangerous in the
sense that it only went off when the danger was immanent and
presumably, this meant that the pilots or air traffic controllers
had already screwed things up. The airlines *did* refuse to give
full authority over the airframe to the TCAS (enabling a flight
control to take automatic evasive action) and insisted that it
provide only a "suggestion" to the pilot because they were
worried about liability. I don't know if they were right or wrong
on this, but other devices on airplanes can and do take authority
away from the pilot under some conditions.

Hope this enlightens.

Pax,
Marin

Marin David Condic, Senior Computer Engineer    ATT:        407.796.8997
M/S 731-93                                      Technet:    796.8997
Pratt & Whitney, GESP                           Internet:   CONDICMA@PWFL.COM
P.O. Box 109600                                 Internet:   MDCONDIC@AOL.COM
West Palm Beach, FL 33410-9600
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