I learned the max was 3 degrees / 15 minutes. My understanding was that if
your gyro precesses more than 3/15, you should not fly IFR with it.

I always thought was too strict given my experience with different gyros; I
don't think any of the planes I've flown in would have passed.

The only source I found for this is the answer to a question in the Gleim
study guide, and it claims the reference is the FAA's "Instrument Flying
Handbook, chapter V".

"Jay Moreland" wrote in message
...
I need to find out if there is an official maximum amount of precession
for a Directional Gyro. My aircraft precesses 10 degrees in 10 minutes
during mostly straight and level flight with only a few shallow banks.

One avionics tech told me that it depends on the gyro manufacturer as to
what is acceptable. He also told me that an out of the box unit tested
on the table should not precess more than ONE degree in four minutes.

Jay Moreland