PPRuNe Forums - View Single Post - TCAS Descend-RA below Min Safe Alt
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Old 18th Oct 2007, 12:49
  #17 (permalink)  
Intruder
 
Join Date: May 2000
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[quote'I am not familiar with the term " wetware" , but I guess you mean : "humanware " correct ?[/quote]
Yes. You need to read a bit more science fiction.

Mixing highly complex automated system with humans reactions has always been a good recipe for disasters, not only in aviation.
I agree here. The problem is that we are going to make the system even more complex, such that it will be even less understandable by the Pilots.

So many solutions : I give you the main 4 : 1 : change/retrain the current pilots and/or replace them by kids that will not challenge computer generated advices, 2 : link ACAS to the auto pilot, 3 : modify the software, 4. Accept a certain non compliance percentage and the accidents/loss of lives that will result because of that non-compliance.
I would prefer #2 for the current generations of airplanes (I fly the 747 Classic, and I doubt it would be included...). I see 2 problems with #3 that will significantly reduce its theoretical effectiveness:

a. Programming in reversals will not be immediately accepted by all Pilots. TCAS has been around for how long now, and we still have incidents caused allegedly because Pilots don't understand the advisories. How can we expect those same Pilots to understand and comply with even more complex commands and maneuvers, especially when there is even less margin for error?

b. There will still be Pilots who ignore TCAS RAs, and controllers who give contravening instructions. With all the increased information going to ATC via Mode S, it is even more likely that a controller will reverse his contravening call in the middle of an incident, at the same time TCAS gives a reversal RA to the other Pilot. Hence, there will likely be as many incidents where an RA reversal will be harmful rather than helpful.


I suspect there were good reasons for programming in the reversal delays/inhibits that are currently in the TCAS RA logic. I can't accept as raw fact the need to change the logic because of a few incidents, including the Ueberlingen mishap. In fact, I submit that it would be better for the education of the Pilots to be monitored by the appropriate regulatory officials in the airlines where non-compliance with RAs is a factor.
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