Calculating crossing time
Thread Starter
Joined: Aug 1998
Posts: 79
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From: BN196R @ 20nm
Calculating crossing time
Has anyone got a quick method for working out crossing time of opposite direction traffic based on estimates?
I heard of a method using the wizzwheel once but can't remember it...
I heard of a method using the wizzwheel once but can't remember it...
Joined: May 2000
Posts: 3,204
Likes: 2
From: Seattle
Using Mach, your Mach number in tenths approx = miles/minute: Mach 0.75 = 7.5 NM/min.
Two head-on aircraft at .75 - .80 will be closing at 15-16 NM/min. With an average detection range of 7 NM, you have 30 seconds or so after visual acquisition. With a nominal 20 NM TCAS display range, you have 1:15 - 1:20 after first display.
Two head-on aircraft at .75 - .80 will be closing at 15-16 NM/min. With an average detection range of 7 NM, you have 30 seconds or so after visual acquisition. With a nominal 20 NM TCAS display range, you have 1:15 - 1:20 after first display.
