Dick Smith Now Blames Virgin Captain, And His lack Of Training.
Join Date: Apr 2002
Location: Sydney
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I see from your profile Karrank that you are the one that sits in the armchair. Maybe you need to revise your understanding of TCAS.
You are correct in that a pilot needs to be proactive in safety. The correct procedure for a TA is to try to visually acquire the traffic. If you cannot acquire the traffic the do nothing (follow your clearance) until a RA occurs. Is this safe, yes. Would I follow this, probably not. I would reduce RoD back to the minumum of 500fpm (which by the way still satisfies an ATC clearance to descend). If I thought that a level off was required to maintain separation, I would request this from ATC. However, I wouldn't turn the aircraft.
Turning an aircraft away from an UNSIGHTED aircraft based on a TCAS TA isn't the correct procedure. For starters the update rate on TCAS is poor, if you look at traffic on the TCAS display and then turn onto a new heading, the traffic moves around significantly before settling down to its new relative position. In the future we will have fast update rates based on transmitted GPS position, which will solve alot of problems.
You are correct in that a pilot needs to be proactive in safety. The correct procedure for a TA is to try to visually acquire the traffic. If you cannot acquire the traffic the do nothing (follow your clearance) until a RA occurs. Is this safe, yes. Would I follow this, probably not. I would reduce RoD back to the minumum of 500fpm (which by the way still satisfies an ATC clearance to descend). If I thought that a level off was required to maintain separation, I would request this from ATC. However, I wouldn't turn the aircraft.
Turning an aircraft away from an UNSIGHTED aircraft based on a TCAS TA isn't the correct procedure. For starters the update rate on TCAS is poor, if you look at traffic on the TCAS display and then turn onto a new heading, the traffic moves around significantly before settling down to its new relative position. In the future we will have fast update rates based on transmitted GPS position, which will solve alot of problems.
Mostly Harmless
Join Date: Nov 1999
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The point is ATSB said everybody done good. To me this means the lateral movement must have been authorised, or somebody has decided it is fair enuf. I don't know which.
If you are correct and lateral movement may compromise the integrity of or prevent an RA, then this is shocking news and controllers all over the world that have absorbed what was thought to be the lessons of Lake Constance need the news now. Otherwise they are poised to make compromised separation situations worse by emergency vectoring.
Are you sure of your facts, or just wafting from your armchair?
If you are correct and lateral movement may compromise the integrity of or prevent an RA, then this is shocking news and controllers all over the world that have absorbed what was thought to be the lessons of Lake Constance need the news now. Otherwise they are poised to make compromised separation situations worse by emergency vectoring.
Are you sure of your facts, or just wafting from your armchair?
Join Date: Aug 2002
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the Virgin pilot was in-correct in turning the aircraft without having visual contact
The turn had nothing to do with the TCAS advice, it was based on a cockpit assessment (approved) based on the traffic advisory.
Post separation breakdown (sic) we are taught to get segregation (if you don't have 5 get 4, don't have 4 get three etc, these option are better than none) when all else fails, we understand that Vertical avoidance isn't ideal as it may conflict with TCAS RA advice... But what has that to do with the turn... Controllers world wide know this and when they are aware of an potential RA, turns is best... IFATCA policy... we learn and adapt...
