Robert M. Gary wrote:
Know how to operate the equipment and not how the equipment operater -

I'm not sure if I'm spending hours with my instructor learning trivia
or useful stuff. However, this is a CFII and not an IR checkride so the
standard for understanding and being able to explain is different.

I've been teaching instruments for a few years, and I think you're
learning useful stuff.

If you don't understand how the equipment operates, the only way you
can learn to operate the equipment is by rote. If you're always flying
with everything multiply redundant, always flying with the same stuff,
and can simply squawk anything out of the ordinary and make it someone
else's problem, you can get by that way if you're willing to memorize a
lot. It's an airline pilot sort of attitude. It doesn't work too well
in GA. The people we train often have only one of something, and thus
an understanding of how it works - and thus of the failure modes -
helps detect failures and understand their impact on the operation.
They usually pay for their own maintenance, and often participate in
the maintenance process, and thus being able to diagnose the failure is
valuable. They also upgrade equipment, and understanding how it works
means not needing to be retrained on every new item.

Michael