Same story - different approach.
Piper Seminole. "Old style". All the switches mounted on the left cabin wall - by the pilots elbow.
Top row has four magneto switches and a two-way rocker switch for engine starting. Second row has landing light, nav lights, strobes, left fuel pump, right fuel pump. Third row just battery and alternator fields.
Cute little (multi-engine qualified) pilot gets airborne, climbs to 1,000 feet agl. and then turns off both fuel pumps at the same time. Problem is, he uses the top row of switches, not the second row. So, both right engine mags are now off - but with good fuel pressure.
The subsequent noises did make me sit up straight.
In a voice one octave louder than normal I emphasised that I had "done nothing - the problem was genuine" (as briefed for any aircraft malfunctions below 3,000 agl.).
I then spotted the cause - the right mags were both off. In a slightly lower voice I explained to pilot that he had turned off the mags and that it would probably reduce our tension if he were to turn both magneto switches back on again.
Now - somebody, please explain to me why the guy turned OFF the two left mags instead of turning ON the two right mags.
Despite a shoulder harness I managed to move sideways at an alarming rate and turned them all back on again.
Circle to land. Flight over!!