Nav8tor
Line Up and Wait
I had an experience last weekend which will lead me to be much more cautious in the future when turning on the master switch. I had heard of hot mags, where the mags can fire even with the mag switch in the off position, but I wasn't aware, until last weekend, that its possible to have a "hot master" condition that will cause the starter to spin the engine as soon as the master is turned on.
After about an hour of flying a C-182, I landed and shut the engine down for about 20 minutes. I got back in the airplane and restarted the engine but right after it started I heard a loud grinding sound what obviously wasn't normal. I immediately thought it was a hung starter but the ammeter looked normal. I pulled the mixture to idle cut off and the engine tried to shut down, but it kept turning over at very low RPM. I turned the the mag switch to off but the engine kept turning. I turned off the master, and the engine finally stopped.
After a minute of so I decided to try starting the engine again to see if the noise occured again, but as soon as I flipped on the master switch the prop started to turn (the mag switch was still in the off position).
I found out the next day that the starter contactor had gone bad, essentially bypassing the starter switch.
In the past I haven't paid very much attention to the prop when turning on the master during preflight because it never dawned on me the the prop could turn, but from now on I'll make sure no one is near the prop any time I flip on the master.
Lee
After about an hour of flying a C-182, I landed and shut the engine down for about 20 minutes. I got back in the airplane and restarted the engine but right after it started I heard a loud grinding sound what obviously wasn't normal. I immediately thought it was a hung starter but the ammeter looked normal. I pulled the mixture to idle cut off and the engine tried to shut down, but it kept turning over at very low RPM. I turned the the mag switch to off but the engine kept turning. I turned off the master, and the engine finally stopped.
After a minute of so I decided to try starting the engine again to see if the noise occured again, but as soon as I flipped on the master switch the prop started to turn (the mag switch was still in the off position).
I found out the next day that the starter contactor had gone bad, essentially bypassing the starter switch.
In the past I haven't paid very much attention to the prop when turning on the master during preflight because it never dawned on me the the prop could turn, but from now on I'll make sure no one is near the prop any time I flip on the master.
Lee