Didn't pay particularly good attention to the pre-flight on an OH-58A. Requirement was to put the throttle at idle and check the pointer position against a mark on the fuel control. It was real close to the mark...
End of a very good flight doing engine offs, and decided to give the student one more as he charged off down the long runway. Rolled the throttle back on my side pretty agressively...
Student reacted very well, and as he's in the flare, I'm wondering 'Why is the low rotor horn on when the collective is full down?? And why is the engine oil pressure dropping to zero??'
Student did a marvellous job of the landing and we sat there watching the rotor slow to a stop.
Throttle was misrigged just enough that a hard movement on the left hand throttle would put it to off.
I learned about pre-flights from that.