The aircraft I was flying today has a push to talk integrated button on each control yoke. I was sitting in the right seat, but my headset was plugged into the jacks on the left side of the cockpit. When I pushed the right mic button, the tower could hear a carrier wave but no voice transmission. It was only when I pushed the left mic button that they could hear my transmission. Is this normal? Seems like pushing either mic button should allow a transmission from either headset.
This is the expected behaviour. The other pilot might make some sound or even talk to someone else. You don't want any noise interfering with your own voice during transmission. Two microphones picking up your voice might also decrease the sound quality because of the small delay between the two locations.
That‘s what is supposed to happen. The person in the right seat might be having a conversation with another passenger and you don’t want their conversation to be transmitted to ATC.
Most audio panels also have a button that lets you isolate the pilot or crew from the rest of the passengers. I use that button all the time when on takeoff and landing so that passengers can continue to talk to each other and I don’t get distracted and miss important checklist items or radio calls.
My audio panel even lets the pilot and co-pilot talk on different frequencies.
We can both be listening and able to talk on Com 1 radio or Com 2 radio. Or the pilot can be on Com 1 and the Co-pilot on Com 2 and vice versa. On my little plane it isn’t too useful, but it can be handy.
The pilot can be monitoring and talking to ATC for flight following while the co-pilot is talking to Flight Services and getting updated weather or filing a PIREP (pilot report of weather). Or if it is a busy frequency, the co-pilot can listen to the ATIS without having to pick out the details over the chatter on the main frequency.
Knowing how this works can be important. I have had the PTT switch fail in flight and the only way to communicate with ATC was to plug the headset into the other set of jacks and use the PTT switch on the other yoke to communicate.