I'm new on G1000 system, it says;

If the push-to-talk (PTT) Key becomes stuck, the COM transmitter stops transmitting after 35 seconds of continuous operation.

I'm wondering if we keep speaking on COM over 35 sec, will it stop transmitting? Or, if I keep PTT open without speaking, will it stop transmitting?

  • $\begingroup$ 35 seconds is a lot of talking, especially in aviation... $\endgroup$ – Ron Beyer Sep 26 '18 at 3:19
  • $\begingroup$ I've done clearance readbacks, where I was instructed to read back all the route waypoints even though we were cleared as filed, that would've taken that much time. $\endgroup$ – John K Sep 26 '18 at 4:10
  • $\begingroup$ If you have more than 35 seconds of talking to do, shouldn't you break that into multiple pieces? "Clearance, blah blah blah blah blah, lots of talking, blah blah blah, break." Wait a few seconds to see if anyone else wants to talk. "Blah blah blah blah blah, over." $\endgroup$ – Tanner Swett Sep 26 '18 at 12:34

I haven't tried it for real with PTT, but from what I know about G1000, it has generic protection against any stuck keys (including those on remote keypads/panels). When a key is detected to be pressed for longer than about 30-35 seconds, it is declared stuck and the respective CAS message appears on the PFD. It is then temporarily disabled; however, when another press is detected, it will work again. You can try it yourself with any of the bezel keys.

In this vein, it doesn't matter if you speak or not. If you keep PTT pressed for longer than 35 s, it will cut the transmission, but if you release and press it again, it will start transmitting again.

(Note that most normal keys in G1000 are activated on release (this is very common in software). But if a key is stuck or you hold it for long, its function will activate after about 0.6-0.8 s anyway. Some keys have 'press and hold' operation (e.g. holding frequency transfer for 2 s tunes in the emergency frequency 121.5), and it will also execute after the elapsed hold time. And only much later the key will be declared stuck.)

  • $\begingroup$ Thanks, appreciate. Perfect explanation. $\endgroup$ – Avenue2Aviator Sep 26 '18 at 9:40

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