A friend of mine recently overhauled the panel on a 182 that he bought, cleaned up, and sold. Sort of a "flip this bird" kinda operation.

Anyway, he wanted to achieve a more modern IFR panel, so he replaced the attitude indicator and altimeter, both of which bench tested OK. He just wanted new ones, and since he owns an avionics retail business, he got good deals on new units.

So, he gave me the old ones. These units are much newer and lighter than the old Jimmy Doolittle era original hardware that came in my 170. The AI and the altimeter both have a TSO number stamped on the little plates on the unit.

Here's my question: Can I install these with just a log entry and signoff from an A&P? My friend, who is an A&P tried to tell me the units are not TSO'd, although they have a TSO number stamped right on them, and they came out of a 182. Is he out of his gourd? What's stopping me from just swapping them?

I swear the original AI weighs more than a starter motor.

I don't think there is any reason an A&P can't just install these instruments via a log entry with an appropriate wt & balance revision if there really is that much of a weight difference. Now, you might want some sort of proof that they came out of such & such Serial No. 182 and were original equipment and/or a copy of the log entry where they were replaced at some time in that aircraft.

I doubt if the original instruments in your steed were TSO'd anyway.
Naturally your AI is the final authority here, if he won't sign your next annual you're SOL.

regards,

Rocky

Zane
Are you driving your gyros with a venturi or venturis? If you are you dont want to replace the old AN style gyros [if thats what you have] with the newer type. The new style requires more suction than the venturis can usually produce and the gyros act sluggish.
Tracy A

Do these new (to Zane) instruments need a yellow tag, or can they be installed as is?
My 170 had new-style horizon and directional gyro's, driven by two venturi's,plumbed into a single vacuum system. Think they were 5" venturi's, but I can't remember.

Eric

I'm sitting behind the ever throaty C-145, so I'm still running off venturis. I have considered the possibility that they might not suck hard enough to run the new AI, so I guess I'll find out.

Eric...yellow tag...hmmm. What means yellow tag? That's for a unit that is tested and returned to service, right? I have no tags of any color.

Yellow tags these days are not necesarily yellow, I guess. Yellow tag = "servicable part tag", or "FAA Form 8130-3 Aiorworthiness approval tag",or "maintenance release". I have yellow tags for various parts labelled as any one of these.
Zane, there's a better than even chance that the radio's in your 170 have a yellow tag taped to the exterior case,slide one out and look at it. Basically sez that the part is airworthy and approved for return to service. Repair outfits yellowtag stuff they fix/overhaul.
Question is whether you need a fresh yellowtag to install used parts in your airplane. Not sure of the legality, maybe an A&P can pipe up?

Eric

Zane,

8 or 9 years ago I ferried a 170 from Plymouth, Mass to Long Beach, CA. The previous owner regularly flew it IFR and had updated the panel from AN gyros to the newer RC Allen types. Not to mention he had also installed about 30K in new King radios. When I got there to pick up the airplane I was surprised to find that the gyros were venturi driven (1 per gyro) which didn't exactly thrill me. My worries, however, were unfounded because they worked great. Had to fly IFR for a good part of the trip and never had a problem. I learned to add the suction gauge to my scan, but always found that it made good suction until slowing below 60 mph. The airplane was also equipped with "instrument air" that bleed suction off of the induction system to spool the gyros up prior to takeoff.

Of course a vacuum pump would be better, but my experience with the venturi's was good.

Matt

I believe to be legal, you would have to have them inspected and yellow tagged. This should not be a big deal, and not terribly expensive. Get it done--you won't be sorry in the long run.

MTV

ShamuPilot wrote: Of course a vacuum pump would be better, but my experience with the venturi's was good.
Matt

I don't know, Matt, I never heard of a venturi having an in-flight failure. The main problem is having to stay VFR for a while after takeoff, to allow venturis to produce anough vacuum to spool up the gyro's-- so no zero-zero takeoffs.After they're up to speed, there's enough spin in the gyro's to maintain proper operation during an approach even if the reduced airspeed causes the suction gauge to read a bit below the green.

Eric

zero.one.victor wrote:Do these new (to Zane) instruments need a yellow tag, or can they be installed as is?
My 170 had new-style horizon and directional gyro's, driven by two

You never, ever, need a yellow tag. The mechanic installing a part is always the final authority as to whether a used part is serviceable.

zero.one.victor wrote:The main problem is having to stay VFR for a while after takeoff, to allow venturis to produce anough vacuum to spool up the gyro's-- so no zero-zero takeoffs.Eric

True, except in this case the aircraft was equipped with what was called "Instrument Air" that you used before takeoff to spool up the gyros. The system used the induction system to add suction to the vacuum system. Basically, it was just knob that you pulled to meter additional suction into the vacuum lines, but you had to be careful because it was capable of adding way too much suction. Of course, since you are now creating an induction leak, the engine ran rough while using it. Good thing was you only needed it for about 30 seconds to get things going.

So...a zero-zero takeoff would be possible, but not with me in the airplane.

-Matt