that was interesting.
Condition Inspection is due. The A&P knows I have a
professional-type Carbon Monoxide detector, and always
asks me to take a flight and log the levels before the
the detector in my shirt pocket, climbed aboard, and put
on my headset. I had switched back to a standard
headset, and decided to do a test transmission before
starting the engine.
Odd. When I hit the Push to Talk switch, I heard three
beeps: beep beep beep.
Huh. Fiddle awhile, then try with the microphone plug
disconnected. Beep beep beep.
Fiddled more. Then unplugged the earphone plug as well,
and hit the PTT. Beep beep beep.
Where is the sound even COMING from. The radio speaker
itself? Shouldn't, with the headphone adaptor plugged
into it, even with no headset attached.
than the warning buzzer for my ejection seat (which
sounds quite different) there were NO other devices with
speaker or beepers installed.
Got out of the plane, switched headsets, and the beeping
was gone. But...shoot, it was beeping WITHOUT a headset
Took the flight. Turned the detector back on (it had
auto-shutoff).... CO at the panel level was a max of 15
PPM during climb, cabin heater on or off. About 6 PPM at
cruise, and during glide. Maximum was a momentary 22 PPM
during full-power climb, measured underneath the panel
between my calves. All well within margins.
Didn't hear any beeping. I tucked the meter back in my
shirt and flew home.
home to land, park in front of the hangar and shut the
When I heard a beep. It was the CO detector doing an
Then it hit. I pulled out the detector and watched its
display as I hit the PTT switch. Reading jumped to ~300
PPM...and the three-beep high-CO warning sounded.
yes, I'll be replacing the compass correction card as part
of the inspection....
detector apparently has some sensitive circuitry; stray
RF from the mighty Icom was messing with it. It had
stopped when I'd switched headsets because it did its
auto-shutdown while I was changing over, and I didn't
turn it on again until I was flying.