Hi Bob and Richard and all,

Resitting Irex tomorrow morning, just wondering if you were given the above instruction from ATC "Stop Squawk" would you:

Change your transponder from Alt to On, or
Change your transponder from Alt to Standby or
Turn your transponder off?

I would normally have selected the Alt to Standby mode - would I be correct in saying this? The reason I ask, is that if you were asked to "Stop ALTITUDE Squawk" then it would make sense to turn Xponder to On from Alt, but if asked to stop "Squawk" then surely this would mean ALL transponder replies, as in puttting the Xponder into Standby mode?

AIP Gen 3-4 - 93defines Stop Squawk as "
"The SSR transponder responses are to be disabled."

(I asked this in an ATC Tower the other day at the ATC guy who was nice and knowledgable couldn't answer it completely)

Brook

Hi Brook,

Take a look at AIP GEN 3.4 5.15.6 (on page AIP GEN 3.4 - 68).

"STOP SQUAWK" means to turn off your SSR transponder completely. It doesn't mean turn to standby mode. If that's what the controller wants, he/she will tell you to "SQUAWK STANDBY".

Good luck tomorrow

Cheers,

Rich

Thanks Rich,

Had a look at the AIP you mentioned, it mentions two states in relation to stop squawk, one was squawk standby, and the other stop squawk, but in both cases they were still to transmit ADS-B messages if fitted, which to me would potentially indicate the transponder would still need to be on?

The ATC guy (as I asked him about turning off the transponder) said "it wouldnt mean to turn off the transponder, but rather to turn it on to On Mode (ie no alt) OR Standby. He said he could not think of a time they would ever ask a pilot to actually turn off a transponder, unless simply for the purpose of restarting (rebooting) the unit, as it would be dangerous to do this, unless this was a formation flight with multiple ACFT with a lead ACFT doing the squawking just to turn off the separation alarms at ATC.

Brook

Interesting. Mind you the formation idea would at least be one reason why the controller would need a way to completely disable your transponder Maybe they would ask them to do that too if the unit was defective? Might have to ask our ATC mate up here next time I see him.

As for needing to keep the transponder on to maintain the ADS-B transmission, the note in the AIP does mention it and explains that ADS-B and the SSR transponder are linked in many aircraft and it may not be possible to isolate the ADS-B transmission. In that case I guess turning the unit off would not be appropriate

What gets me is the meaning of "termination of SSR transponder ... operation". To me, "terminating operation" sounds very final i.e. like killing the SSR functionality completely. But, your ATC guy would be in the know so it is good to get his take on it!

Cheers,

Rich

Thanks Rich,

Will be interesting to hear your ATC guy's views. I like the idea of a comedy movie, called T2 Transponder, the Terminator...

In my best Arnie voice "Hold Still and stop Squawking, or I'll terminate you..."

Thanks Bob and Richard - I passed today at Archerfield Qld. Unless I am mistaken, the resit was much easier than the original, but there you go. Persistence can either pay or, or just mean you are stupid, I'm just deciding which one

Have a good weekend, and thanks for a great Book on Irex, its a challenging subject to keep on top of, and a challenging exam.

Brook

Congratulations Brook!

Now for the fun part.................

Bob

Yay Brook! Well done mate! Onwards and ever Upwards!

Cheers,

Rich

Thanks Bob and Richard!

Couldn't have done it without you! Think of me as your disciple I have take all 8 oaths of a commercial pilot I will still drop in on the forum from time to time and Redcliffe of course, when next up that way! Now Richard is back I can meet him too!

And with any luck I might fly again soon

I'll let you know when I get the piece of paper (CPL first) soon! Start back in WA in a C172 then a Piper, starting to miss the family and the C172's are a bit nicer than the Socata TB10's in terms of ROC.

Brook