The International Cessna 170 Association

Hello,

I finally made the headfirst plunge into the world of aviation here recently with the purchase of a 1955 170B. I am also working on my ground school and have my first flight lesson here in a couple days! Super excited!

The plane was annualled and a pre-buy inspection was done with only minor issues which were all fixed. There are 2 gauges that the prior owner said were inoperable (Directional Gyro, and Attitude Indicator). The mechanic said that the vacumm hoses were loose and he thought that my tigntening them that they would probably work, well they don't.

Several questions:

Do you need these gauges to complete the IFR part of flight training, the part with goggles?

Because of the shroud (red covering in the attached pix) will I need unique gauges, or will any 3 1/8" vacuum gauges work?

Thanks!

Tom

You might check a few other things. First is there a filter on the gyros. If so replacing them might help. If your instruments have no filters you might check to see if the inlet screens are plugged with lint. Another possibility would be old vacuum hoses that are cracked. Bill K

Adding on to my previous post. You will need them to operate properly to take a complete private pilot check ride in that airplane. You should have them working because similar to a gun or a parachute the day you realize you need one its going to be too late to buy one. Bill K

3958v wrote:Adding on to my previous post. You will need them to operate properly to take a complete private pilot check ride in that airplane. You should have them working because similar to a gun or a parachute the day you realize you need one its going to be too late to buy one. Bill K

Need and want are two different things. There is nothing in the regs that says that you MUST have working gyros for a checkride. Having said that, it is going to make some maneuvers (steep turns come to mind) much easier.

If it were me, I'd look into getting the DG overhauled, but replace the attitude indicator with a modern one, even if it's used. You can't undrill a hole or ungrind a notch, and with a cover panel that pristine, taking a Dremel to it would give me pause. The other option would be to remove the cover panel totally, re-arrange the instruments to a more standard arrangement, cut a new flat panel, and sell the floating panel to save weight. There are CAD files out there that exist for the upper panel for your airplane that would be easy enough to plop a few instrument holes in, and use all modern gyros.

What's your end goal? I would venture to say you'll end up getting those instruments out of there when you use the airplane as I suspect. Replacement down the road with something like dual G5s (if you'd like to be IFR-certified, or single if you like the additional data/security for VFR) or removal totally (if you plan to remain hardcore VFR) is certainly going to lighten the airplane up for backcountry flying.

Keep the purists in mind if you decide to start tossing things to save weight. Hat shelves, panel parts, interior trim pieces, seat skirts, etc., don't do anyone up there a lot of good, but are hard to find for those that want to keep their Sunday driver in tip-top shape.

Looks like a beautiful airplane! Best of luck with your training. I only wish I lived closer.

Yes you will probably need them for training and Yes...because the regulations also require that they be operable if-installed. (Unless there exists an Approved Minimum Equipment List (MEL) the installed equipment must be operational. Since you are a new owner, any previously-approved MEL is not likely applicable. You should either repair/replace or remove them. (There are some exceptions but generally speaking, you will still want to repair them.)
See: http://www.faa-aircraft-certification.c ... pment.html

gahorn wrote:... Yes...because the regulations also require that they be operable if-installed.

The way I read FAR 91.213 you are completely legal with the instruments placarded inop. provided that there is an entry in the maintenance log to go along with that action. The FAR starts with "Except as provided in paragraph (d) of this section" ... . Here's paragraph (d):

(d) Except for operations conducted in accordance with paragraph (a) or (c) of this section, a person may takeoff an aircraft in operations conducted under this part with inoperative instruments and equipment without an approved Minimum Equipment List provided—
...
(3) The inoperative instruments and equipment are—
...
(ii) Deactivated and placarded “Inoperative.” If deactivation of the inoperative instrument or equipment involves maintenance, it must be accomplished and recorded in accordance with part 43 of this chapter;

In other words, forget all the mumbo-jumbo about MELs. You can placard the instrument "inop" if it's not required for the type of flying you're doing. That being said, I still agree with George's conclusion:

You should either repair/replace or remove them.

I agree with Bill's idea's on troubleshooting;

3958v wrote:You might check a few other things. First is there a filter on the gyros. If so replacing them might help. If your instruments have no filters you might check to see if the inlet screens are plugged with lint. Another possibility would be old vacuum hoses that are cracked. Bill K

You could be showing adequate suction but if the filters or screens are clogged you won't be getting adequate flow to turn the gyros. If both instruments went belly up at the same time I'd also be checking the suction relief valve as seen in Fig. 77 of the IPC:

Nice looking airplane! Welcome to the Assn and the wonderful world of 170 flying.

Just a couple points of clarification:

1) To complete his Private Pilot Check Ride in that airplane, the gyros would have to work, as Area of Operation VIII is Basic Instrument Maneuvers and must be completed. The ACS says that the Appplicant must provide an aircraft that is capable of completing all the maneuvers. An alternative would be to use the 170 for most of Check Ride, and another instrument equipped aircraft for AO VIII.

2) The FAA has flip/ flopped on INOP Equipment. Here is the latest: https://pilot-protection-services.aopa. ... -equipment

Tom, welcome to the 170 assn. Also, welcome to the 170 world. You will have a ball with your 170. Always feel comfortable contacting the assn or individual members with questions about your plane. There is a world of information available here. Although some may disagree, I think you have the best model (55) of the 170's. Get that certificate and fly the wings off of it!

Thank you all for your responses! It is like drinking from a fire hose at times, but I am learning a lot. I have my first lesson with a instructor tomorrow, super excited, but also nervous. A friend and I flew the plane from Fairbanks (where I purchased it) to a strip near where I live north of Anchorage. It took us about 2 1/2 hours. It was a gorgeous day and we flew by Mt. McKinley or Denali as they now call it.

IA DPE wrote:Nice looking airplane! Welcome to the Assn and the wonderful world of 170 flying.

2) The FAA has flip/ flopped on INOP Equipment. Here is the latest: https://pilot-protection-services.aopa. ... -equipment

Thanks for the AOPA reference, it certainly adds some clarity to this issue.

In my opinion you should get those two old gyros working. Get them overhauled, replace the hoses and filter (if any), and get on with your training. I know there’s a strong anti-instrument sentiment in Alaska, but those instruments will be useful in your training and could save your a$$ someday.

Get under the panel and see what’s there. That’ll help tell you the path forward. Don’t be too eager to toss what’s there and replace it with something “ modern”. Many cans of worms await, even in seemingly simple stuff like this. You don’t want to start a project at this point.

Thanks Dave. It will be interesting to see what my instructor has to say about it tomorrow. With winter coming on, and the daylight quickly getting shorter, my window for training is quickly shrinking. Hoping I can start, and get these fixed or replaced at a later date.

I agree with your priorities. Fly while the weather cooperates!

I am not sure about the “Alaskan anti-instrument sentiment “ comment come but consider this... night VFR is a lot safer with a DG and an attitude indicator. And for the next 4 months, we are going to have a lot of night time.

In good clear weather, Anchorage, not to mention the Moon and the stars, will make local night VFR a very pleasant experience but as you depart from BCV headed to Talkeetna, you might really appreciate having those extra instruments.

Pete,
I meant that I met a lot of guys in Alaska who preferred scud running to any kind of instrument flying, as if it were effete, or a weakness. I was trying to nudge Tom in the right direction, just in case he knew some of the scud crowd. Maybe I misinterpreted or improperly extrapolated to the Alaska pilot population. Sorry if I did.

Dave