C-172 Dg
 

I have a C-172 on leaseback to a Flight School. I have been replacing DG's about every three months. They are not using it for "spin" training, just normal Privat/Instrument work. Out of 5 C-172's, mine is the only one going through DG's. The C-150 that used for spin training has not had one fail yet. The suction is in the green at cruise power. All the filters get changed every 100 hours (I usually do all the 100 hr Insp.).

Any thoughts?

Something's up. Are you 100% sure they aren't spinning/attempting to spin it? It just doesn't seem right, I got a lot of time doing "spin entry" in a 172, it won't actually spin well, but it will do the initial entry well. I'm just skeptical probably in the same sense you are.

Sound like it's being spun.

The school might be BS-ing you, or worse, they might have a rogue instructor or even student who likes to do illicit spins for fun.

I have a though, but it's not about how to fix your DG (which is being spun).
Ready for it? Here it is:
Don't let a flight school use your plane. No matter how much money you save by putting it in a revenue-earning venture, you'll lose it all when it has to go to the shop repeatedly because the students and instructors don't care how trashed the plane gets. After all, it's not their plane!
Plus, you can't even fly your own plane when the students aren't using it because...it's in the shop!

are they putting a new DG, or repairing the DG?

I have been sending the DG's out to be rebuilt. I am pretty confident it is not being spun time and time again. I am out at the school quite often and fly my plane pretty regularly. They have a 152 that they use primarily for spin awareness training.

I am wondering if the regulator could be bad and/or the suction gage not acurate???::confused:

Ask the shop doing the overhauls the reason for the failures.

Check the suction gauge.. my my first guess would be that you might have some old rubber hoses in your vacuum system. If one of the hoses is breaking down and the particles are breaking down, they can be sucked into the gyros or the vacuum pump.

Also, make sure all the filters - the big one and the small, sock one, are replaced each time the a vacuum instrument or pump are replaced.

jeremy