My recollection from FW training is that you want to see a positive drop to confirm you have actually isolated one - not seeing a drop when selecting either L or R would seem to match the fault in the original accident topic.
Nothing wrong with your memory
212man, max permitted drop in the -44 is 7%, which equates to 187 RPM, the Lycoming manual for the engine says max of 175 RPM drop with 50 RPM max difference between mags. If you don't see a drop you have problems, the mag you have supposedly turned "off" is still live and producing a spark.
Not much point fitting a four-point harness if it's not worn correctly
You'd think an instructor would know how to wear seat belts, low on the hips, else you'll submarine right on out of there.
Posted to clear up discussion on mag switch positions. Cockpit switch confusion by the pilot flying a mixed fleet? Cause of crashes and deaths in the airline industry..
A tired mag will approach the 7% in 2 second limit, so not long in that case. I brand new mag can take 5 or even 10 seconds to show even a small drop, say 2%. One must be careful and patient to detect a bad P lead. I suspect most do it by ear, but I like to visualize a discrete drop in RPM. In any case the check is eminently practical.
Can you give an explanation to your statement as to why?