That’s interesting. It should be in the shutdown checklist.
I’ve never seen it in an official (POH) checklist for Cessnas AFAIR. I’ve seen it in custom check lists from flight schools.
Aviathor wrote:
In Norway where I got my PPL there was emphasis on this item.
I trained in the US and hence learned it the same way, but when I came back to Germany and began chartering, instructors told me “we don’t do that here because of potential engine damage”.
Now, I’d prefer doing it but it’s useless if only I do it and any other person flying the airplane doesn’t do it, right? It’s useless for me. And it’s more or less useless for the next pilot because they wouldn’t assume I’ve done the check. I do understand that even if everyone does the check, you should always treat the prop as live etc.
If I’m taking a Cessna for a consecutive number of flights i.e. a multi day trip, I think next time I’ll reintroduce the idle-check for my own sake. 
Aviathor wrote:
Patrick wrote:
As far as I was told (when asking people why the idle-check before shut down is neccessary), the OFF switch is wired independently and hence, confirming a drop on L and R still leaves a chance of a broken wire from the OFF switch (and hence, a potentially live prop). What I don’t know is if the independent wiring is an OWT or not.
This is not true. There is only one ground wire (called P lead) from the switch to the LH magneto, and one P lead from the switch to the RH magneto. The switching mechanisme in the switch, ensures either:
- both open, magnetos live / hot
- RH closed to ground disabling RH magneto, LH magneto open, thus live / hot
- LH closed to ground disabling LH magneto, RH magneto open, thus live / hot
- both closed, magento’s dead.
View from the switch: (source: internet)
It is still possible that the switch itself is defective – for example, the internal contact surface for the off position could be corroded, while the contact aurface for the same mag in both and single positions is fine. So a L/r check only won’t rule out that failure.
Cobalt wrote:
So a L/r check only won’t rule out that failure.
Correct, one needs to do both. Just remember no drop on L/R check is not good.
This morning I woke up having dreamed of a large group of people walking into my hangar, looking around at everything while I fiddled with something on the tail of my plane. Just then something I did caused the engine to start and the people all turned around to look, all smiling and curious…. I’m glad at that point I woke up!
Maybe I should stop reading threads like this… but regardless I do shut off both my planes with the mag switch, at least occasionally. One of them every time because that’s the only way to do shut it down.
