I use to work on F15 Fighters in the Air Force. One day a Pilot called an emergency Service call at the end of the Runway. I had him shut down the Engine then I opened the side panel plugged in my headphones and talked to him. I said try it now. He said it works great and gave me a thumbs up.
I closed the side panel and he started the Engine back up. I kicked the Chocks for him and Away he went like a birdy in the sky.
When I filled out the paperwork I wrote "Short between the Headsets"
He read it later and he was Tee'd off. I kind of got in trouble for that one.