On Sun, 03 Aug 2003 00:27:50 GMT, "Marty Ross"
wrote:

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 don't have to reset mine in an hours flight (IE I don't notice any
precession in an hour)t. If I had to reset it more than once every
half hour I'd get it replaced.

I've not noticed a need to reset it even after doing a series of
s-turns and steep turns. OTOH after doing stalls when I'm a bit
rusty, I have had to reset it.

As I recall and it has been a long time, we used to reset the DG in
the Cherokee 180 about once every half hour.

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.

I've seen very few that wouldn't pass 3/15, but then again we had a
Mooney on the field that went through 3 DGs in one year. I, and
they...have no idea as to why The filter on each appeared to be fine.

The one they have in there now has been going for at least three
years. The one in the Deb was in it when I purchased the plane.

I wouldn't hesitate to replace one drifting 10 degrees in 10 minutes
as a personal choice.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)


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