Originally Posted by
piperboy84
PBF
Sorry can you clarify, are you saying doing a quick OFF then back to BOTH quickly is not really of value due to the remote chance of this OFF function is not working properly as opposed to the risk of not doing it quick enough and causing a backfire with potential hardware damage
No I never switch the mags off with the engine running. Cycling the mags Both/Left/Both/Right/Both, and observing the RPM drop and engine sound change as each mag individual cuts out will prove the mags are properly grounded.
The chance that the mags would cut out normally when the switch is in the left or right position but then not cut out in the off position and thus leave the prop hot is IMO very small.
A more tangible danger IMO is slipping the key out when the mag is in the "right" position but you thinking it is in the off position, something I have personally seen was possible to do in two old worn out switches. The logical time to give the key a tug to make sure it does not come out except in the off position is when you do a Both/Left/Both/Right/Both check at shut down.
The "live mag" check where you turn the switch to off and listen for the engine to die does not check for this fault and as I have said in my earlier post will damage the engine if you are slow turning the mags back on.