Jes and I tried to go flying today, but it just didn’t work out. The weather looked like it would be ok for local work, overcast at 5000′, but just before take off we ran into some problems.
I went through the pre-flight inspection like normal, and taxied over to the run-up area. The run-up went fine, so I requested and was approved for a taxi to the runway. Unfortunately, or fortunately as it turned out, there were four or five planes coming in for a landing that I need to wait for before taking off.
While we waited for a couple minutes for the traffic to clear, we both noticed a buzzing sound every few seconds. It almost sounded like the wind gusting against the stall warning vain, but the pitch wasn’t quite right. Slowly the buzzing turned into more of a pulsing alarm like sound and grew louder, and we realized that it was coming from the cockpit radio speaker. We tried to figure out what was causing the sound by turning some equipment off, but I didn’t want to do too much testing while waiting for the tower to clear me for take-off.
When the tower did call us back, they’d lost our request and asked us what we wanted. I requested to taxi back to the run-up area. The controller said it would be a bit before he could do that and got another plane out before us. Once there was a small break in the traffic, he asked be to quickly taxi across the runway to do the run-up on the north side. By then, the buzzing had become quite loud (even with our headsets on) and constant.
In the north run-up area, we tried turning off all of the radio equipment and turned it back on, but the problem persisted. We tried checking out a few more things, but it was pretty clear that we weren’t going to get it fixed, and if anything, the problem was getting worse. I requested to taxi back to parking and explained that I was having a radio problem. The controller was very nice and helped us get back to parking. Once I had the plane parked and turned off, I tried checking out the radios one last time. It was find for about 30 seconds, but then the problem returned — even with the engine turned off.
I went ahead and wrote up a problem report in the plane’s notebook. When I got home I called the maintenance captain and explained the problem. Now the plane in grounded until a radio mechanic can check it out. Hopefully they’ll find the problem and have the plane fixed soon.