Originally Posted by
JohnBurke
Two of the best initial instructors that I've had throughout my career, had no instructor certification, and they weren't pilots.
Flight engineers, both. Not just sharp on systems or the other material, but outstanding instructors, too. Unfortunately, both retired, now.
I can second that. One was an Electra engineer, another a Navy DC6 (or whatever the Navy called them) flight engineer. Never had a systems instructor since then that came close. My initial 727 Ground school instructor was a retired Pan Am FE. All had very extensive experience and a calm confident (deservedly so ) demeanor. None had a CFI or AGI.