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OCEAN WUN ZERO
16th Oct 2006, 21:58
There seems to be a lot of RA's and TA's being reported by CAT traffic at an Airport near you, that are allegedly caused by Aircraft on the ground or waiting to join the pattern.
Can anyone come up with the rules and regs on this and or best practice?
One thought is that TCAS alerts are inhibited below 1000 ft AGL and therefore they should not be happening
Thanks in advance
OWZ
:)

chevvron
17th Oct 2006, 07:59
I understand Gatwick departures often get TA's on traffic climbing (but below 1000ft) in the Redhill circuit.
And I've got another advert on my panel.

GT3
17th Oct 2006, 16:09
TAs can be generated if the "conflicting" traffic does not have Mode C selected.

Minesapint
17th Oct 2006, 19:34
TCAS 'looks; at all other targets with approximately 14Nm. The only restrictions concern transponder procedures on the ground (I understand). I have been sent a presentation, PM me if you want me to send it to you.

Dan Dare
18th Oct 2006, 09:21
I've had pilots report spurious RAs both on departure and on arrival close to different airports over the years with nothing seen on the radar (nor out of the window). I have suspected TCAS interogating itself via ground reflections. Others could be against aircraft alreading squawking on the ground as happens more often in these days of A-SMGCS. Either way I have filed the appropriate reports so that minds immesurable superior to mine can regard them...

West Coast
20th Oct 2006, 03:19
Not against ground reflection, but other txponders. Note I didn't say aircraft. We received a briefing item a while ago about bogus TA/RA's landing 19R at KSNA. There is an avionics shop of some sort on the final that sets the boxes off on occasion.

Stanley Eevil
20th Oct 2006, 07:30
My TCAS installation (Honeywell) reverts to TA only descending thro` approx 900FT AGL and restores full TA/RA passing approx 1100ft in the climb. Of course there are all the other `Version 7` inhibits as well e.g. no audio warnings whatsoever below a certain radio altitude. Should never get RAs in the last 900ft of an approach.