Hello can someone please explain how the TCAS is handled when on a NAT track over the Atlantic 1000 ft apart. How do pilots deal with the Traffic and RA warnings since these are activated within 6 miles and a 1200 ft of another aircraft and still fly on the NAT Track? Thank you :-)

Hi there,if that were the case, then you couldn't fly in most of Europe! :-)TCAS' sensitivity was reduced after many nuissance RA's were created.Anyway, TCAS won't automatically issue an RA at 1200 ft, it all depends on the closure rate. Therefore. crews are encouraged to reduce vertical speed to below 500 fpm for the last 500 feet of the climb/descent. (Example: you are climbing to FL190 at 3500 fpm, at FL185 you reduce climb rate to 500 fpm). This way you won't cause nuissance RA's.Regards,Mark

TCAS II v7 is RVSM-compliant. You will not get an RA for 1000ft vertical separation if you're both level. From about FL200 to FL420 the RA threshold is only 800ft. Above FL420 it is 1200ft, but that is above RVSM, right?You will get TAs though for a 1000ft separation encounter. That is just to raise your awareness and help you to visually see the other aircraft.6-miles and 1200ft are the thresholds for "proximate traffic", nothing more.Lee Hetherington, PP-ASEL (KBED)