PREFLIGHT WHAT AM I? BY JILL W. TALLMAN PUSH-TO-TALK SWITCH HELLO? IS IT ME YOU'RE LOOKING FOR? SHOW ME THE PTT IT'S SAID THAT THE ORIGIN OF CUTTING A STUDENT PILOT'S SHIRTTAIL ON SOLO DAY COMES jill.tallman@aopa.org 12 FLIGHT TRAINING JANUARY/FEBRUARY 2021 Yoke Joystick Handheld microphone MIKE FIZER from a time when there were no radios in airplanes, and the only way a flight instructor could communicate with a student (presumably in a tandem aircraft) was to tug on their shirt. No shirttail means no more instructions from the flight instructor; at least during that solo. Radios became more available in general aviation aircraft in the 1930s. The radio receives and transmits analog signals via very high frequency or high frequency radio waves. Radio calls were made using a separate handheld microphone connected to the panel by a cord. You can still find handheld mics banging around in a lot of older airplanes. Before headsets and intercoms became popular, you listened through a speaker often mounted overhead. The next step up the tech ladder is a push-to-talk switch. Commonly installed on the yoke within easy reach of your index finger, the push-to-talk (or PTT) switch is connected to either the radio or audio panel, and it does what its name implies: You push it and hold it down when you want to transmit on the radio; you leave it alone the rest of the time. Radio calls are received and transmitted from the radio through your headset, which is also connected to either the radio or audio panel. When you push the PTT switch, you know you're transmitting when you see a " T " display on your communications radio. PTT switches can and do fail, which could prevent you from transmitting. If the switch fails in the off mode and you happen to be one of those canny pilots who held onto a handheld mic, you can use that to transmit in a pinch. Or you could reach over to the other yoke and use that PTT (or ask your right-seater to do so). If the PTT fails in the transmit mode-which you will know if you see a continuous " T " displayed on the comm radio-your best bet may be to turn off the radio. Nervous student pilots have been known to keep depressing the PTT switch even after they've finished their radio call. This is not a sin and it's not the end of the world; at worst the pilots on your frequency will hear you talking to your flight instructor. (So be nice to your flight instructor.)