TCAS warning calcu.??

[kkuuff]

Anyone can help me with this question??

Two aircraft flying at 33,000 ft with an IAS of 270 kts and are entitled to each other. The planes are 900 Nm apart. Work out how long it takes until the TCAS Resolution Advisory system and will assume no wind (the TCAS resolution advisory system gives a 25 seconds before impact):
• Temperature at sea level is 10 ° C
• Pressure at sea level is 1020 Hpa
• Temperature at 33,000 ft is -62 º C

[aviatorhi]

Exactly one hour.

[kkuuff]

TAS=IAS*(1+(33.000/1000*0,02) = 448,2kts (230m/s)

450nm = 833400m
(833.400/230)= 3.623,48sec till impact

(3.623,48-25)/3600= 0,9995 = 1hr

????????

[powerstall]

Say again? you lost me at hello? :E

[Slasher]

Yep one hour, near enough.

[nitpicker330]

What, who asks this kind of rubbish?

[Checkboard]

They are "entitled to each other"? :confused:

... and I thought I was a native English speaker ... :hmm:

[MetoPower]

As the TCAS warning is given in accordance to a time to impact, and that you have them flying at the same flight level, the smaller the angle of convergence, the longer it would take.
And as you start with 900 Nm (this would be left or right, and ... say ½ a degree angle convergence), they could eventually run short of fuel before anything else....(according to type and fuel in tanks of course) ;)

MP

[Da-20 monkey]

After the compressibility correction I find a TAS of 430 kts.

[kkuuff]

I'm just an aviation engineering student looking for answers for my aerodynamics test in a couple of days.

All thanks for your input. I believe the calc i made is correct.