The International Cessna^® 170 Association

Greetings,

First post here! I am fortunate enough to know a fellow who lets me fly his 1954 170B regularly. It is well equipped in the avionics department, but has a bad attitude indicator. (belt driven vacuum system)


I plan to replace with a new one as I want to fly in light IFR (climbing through cloud decks, etc), however, I have a few concerns. The panel is fairly loose: that is, if you pull all the way back on the yoke, one of the instruments contacts the control column and the panel angles slightly out. Wouldn't a loose panel like this affect the attitude indicator's indications? The panel doesn't seem to be very rigid. The fellow who owns it is an A&P, but doesn't do any instrument flying and therefore has very little interest in working on it himself- but has told me I could get a new indicator if that's what I want to use it for and he'd install it. I figure it's the least I can do since he's let me get a LOT of free flying in it, but don't want to sink $700 into a fix that may still not work real well. Any insights would be greatly appreciated.

Regards,
-Pat-


[/img]

the panel isn't loose, but either the yoke travel is misrigged or the instrument installations that exist were done wrong, so that clearance behind the panel isn't there at full travel. nothing should be interfering at all, ever, during any portion of the control travel.

most of the panels of vintage aircraft are a "floating" design, either mounted with rubber shock mounts or rubber isolators that have screws molded into the ends. so it is supposed to have a little give. although while your mechanic is in there fixing this problem, they should check the isolator mounts because they often shear from old age.

once the clearance/rigging problem is fixed, and the panel mounts are checked up to snuff, then the panel will be robust enough to handle the gyro and any normal vibrations. if it is vibrating enough that it affects gyros, then your fillings are probably also swapping teeth and you have other major issues with the airplane!

HA is correct, although I would add that you might want to check the panel shock mounts. If the panel IS moving, you may have to replace a few. I had a couple go just from age... the rubber gets dry and all that vibration takes a toll after 50 years.

If the location of the added on attitude indicator interferes with full movement of the control yoke, the airplane is not airworthy.