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Squawking in the circuit

Hello,

I have just been involved in a discussion with a fellow PPL'er about what to squawk in the circuit, with me been someone who squawks standby (although today was C with a squawk due to I believe the primary radar been U/S) and him someone who squawks C7000.

The reasoning behind his decision to squawk C in the circuit was so that any TCAS equipped aircraft could see him. However I argued that this could possibly be a problem at a larger airfield that if you flew a tight circuit and set off a TA/RA the TCAS aircraft would have to execute the resolution (and create an unhappy crew) even though we were clearly in sight and avoiding.

Therefore my question is - is there a correct procedure on what to squawk in the circuit?

Thanks

In my very LTD experience you would squawk whatever the tower told you to squawk?
If you are expecting the heavy’s around then there must be a tower therefore do as you told?

YYZ

This subject was covered in GASIL 4 of 2002

Quote:

Transponder use in the circuit

For many years we have been advising pilots to use their transponders at all times, “squawking” both mode A and mode C, except in the visual circuit pattern. With the increasing use of airborne collision avoidance systems (ACAS) in commercial aircraft, it has been decided to update the published procedures. The UKAIP is about to be amended to reflect these.

Whenever possible, pilots with a serviceable transponder should select and transmit code 7000 with altitude reporting (mode C) at all times, unless one of the following conditions apply:

• An air traffic service unit has allocated a different code

• A Special purpose code (such as the distress code of 7700) is more appropriate

• The aircraft is operating within a visual circuit and local procedures require the transponder to be set to standby

The change means that while previously pilots were asked to switch the transponder to STANDBY when in an aerodrome traffic pattern, unless instructed otherwise, we are now asking you to keep it on ALT (ON with mode C) unless instructed otherwise.

Transponder and TCAS in the circuit is not a problem (any longer, was with the early TCAS versions)

We have lots of light GA and MIL trainers at our base, as well as 2 helo Sqns......everyone squawks mode C at all times, and we have never had a TCAS RA on traffic in the circuit!

I have still to hear one single vaild argument to squawk STBY at any time.... :8

Negative Charlie

The GASIL advice asks to sqwark modes A and C at all times...

We don't have Mode C, so when at a non-radar unit, I tend to sqwark standby - especially if there are other aircraft in the circuit that look like they'd have a Mode C capable transponder: that's enough to alert passers by that the circuit is active.

While this discussion seems to be centered around procedures in the UK, as a general note I would reccomend keeping the txponder on at all times. You may not have TCAS, but I do. Because of that, you to a degree are safer as I will find you even if you don't know I'm there. As such we are both better off.

Leave it on unless someone asks you to turn it off. There are a few specific circumstances where the picture will get garbled and ATC will request you to switch off.

Hello,

Thank you for your comments and replies, very helpful.

Cheers