unidentified traffic

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i understand that controllers can not rely on the mode C if it is not verified.
but is the flight level of this unidentified traffic shown on the TCAS of another aircraft correct?

[Spitoon]

It's probably what the other aircraft's mode C is reporting. But that's the best anyone can say. :(

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am i correct to say controllers need to verify the level on the TCAS before relying on it?

[HEATHROW DIRECTOR]

There is no ATC procedure for verifying TCAS info that I'm aware of. Why should ATC need to "rely" on TCAS?

[dudduddud]

It is my understanding mode C alt. needs verification as it is a raw pressure altitude reading, most likely subject to different temp and pressure as ATC.
Mode C or S alt. verification probably not such an issue with aeroplanes involved in a TCAS situation as they're in the same airmass.

Standing Corrected................................................... ............stby

[HEATHROW DIRECTOR]

<<It is my understanding mode C alt. needs verification >>

Correct - so that ATC knows that the data visible on the radar display is correct. Sometimes the a/c altitude and the Mode C readout are different due to a fault in the a/c transponder. The best ones are those which come up with a minus sign in front of the altitude... we always assumed they were submarines!

However, ATC does not require to verify TCAS as there would be no requirement.

[AerocatS2A]

I was heading into Christchurch in a C172 once and the controller had me at FL600, he was concerned (in a joking way) that I might be conflicting with the inbound Concorde.

[HEATHROW DIRECTOR]

<<I was heading into Christchurch in a C172 once and the controller had me at FL600, he was concerned (in a joking way) that I might be conflicting with the inbound Concorde.>>

Hope you got the transponder fixed!!

[push&stop]

thanks for the replies

mode c definitely needs verifying.

i was saying if the unidentified traffic is not squawking c, only on some military code, does the level shown on the TCAS of another traffic need verifying?

TCAS can pick up any code,correct?

[HEATHROW DIRECTOR]

<<mode c definitely needs verifying.

i was saying if the unidentified traffic is not squawking c, only on some military code, does the level shown on the TCAS of another traffic need verifying?>>

Not sure I wholly understand what you mean. Mode C needs verifying for ATC purposes but there is no procedure for a/c equipped with TCAS to verify the equipment on another aircraft.

So far as I am aware, TCAS will indicate any a/c which is sqawking, irrespective of the code selected on the transponder and irrespective if that code has been allocated for a military or civil flight.. No doubt a pilot will comment on this..

[BOAC]

HD wrote:<<I was heading into Christchurch in a C172 once and the controller had me at FL600, he was concerned (in a joking way) that I might be conflicting with the inbound Concorde.>>

Hope you got the transponder fixed!!
....or the 172:D