The International Cessna 170 Association

My venturi driven DGI and AH are becoming increasingly unreliable and I've been pondering the feasibility of replacing these with Garmin G5 (or similar) instruments.

If anybody has done this, or explored doing it, I'd like to hear your experiences.

Thanks,

Mike

Please keep us posted on how you get on as I am in the same boat [well aeroplane] . I want to fit the G5 but can’t get the info on what instruments have to stay . But I do want to get rid of all my Venturi driven instruments and have another STC.

I think you’d have to retain the Magnetic Compass, analog Altimeter and Airspeed as mechanical backup. If/ when I do mine (for the same reasons you cite), that is my intent.

Advisory Circular 23.1311-1C contains guidance for FAR 23 certified airplanes though the 170 was certified under CARs.

https://www.faa.gov/documentLibrary/med ... 311-1C.pdf

https://sandia.aero/wp-content/uploads/ ... -23-08.pdf

If you follow the guidelines posted, you must conscientiously check main ship's battery charge-condition prior to takeoff. (We should all be doing that anyway...but emphasis is added.)
Notice also that ... The existing airspeed, altitude, and turn/bank indicators must remain in their originally certificated or basic “T” locations.

In other words, you must not alter the position Cessna placed the airspeed, altimeter and T&B...unless you've already obtained approval-basis for the redesign of your instrument panel. Consider the fact that (for example) in the later B-models, the T&B was directly in front of the pilot.

Where are you planning on installing that new G5?

gahorn wrote:If you follow the guidelines posted, you must conscientiously check main ship's battery charge-condition prior to takeoff. (We should all be doing that anyway...but emphasis is added.)
Notice also that ... The existing airspeed, altitude, and turn/bank indicators must remain in their originally certificated or basic “T” locations.

In other words, you must not alter the position Cessna placed the airspeed, altimeter and T&B...unless you've already obtained approval-basis for the redesign of your instrument panel. Consider the fact that (for example) in the later B-models, the T&B was directly in front of the pilot.

Where are you planning on installing that new G5?

I was planning to replace the AH and DG with Certificated Garmin G5's. Certainly no different than replacing a venturi driven DGI with an electrically driven DG. And I was planning on doing it through an approved facility.

The Garmin G5 is STCed for the 170 and you could probably put it in the AH panel hole with no issues other than possible control yoke clearance problems. Since the 170 never had a "T" or six pack configuration I don't think it would be an issue moving instruments IF necessary.

Karl, that was the question raised when the policy statement is: The existing airspeed, altitude, and turn/bank indicators must remain in their originally certificated or basic “T” locations.
Since there never was a Basic-T.... then the T&B etc must remain where Cessna put them..unless another basis of approval is met. At least that's the way it reads(Perhaps the STC you mention already covers that relocation issue?)

Since this policy statement is in regards to Part 23 certified aircraft I'm not sure it even applies to our CAR 3 certified aircraft, but your point is taken. Under CAR 3 it only states that the instruments must be "easily visible" (CAR 3 3.655) I see no mention of specific positions for instruments.

It’s the turn and bank is my issue as it’s venturi driven . I will be guided with what Karl said as per CAR3 3.655 . Also it’s my turn and bank is giving me grief also. No body is interested in overhauling either. The cost of a new one is slightly less than a G5.

I'm planning this exact upgrade, Garmin G5 to replace artificial horizon plus the extra details it provides. It will also replace an older electric T & B with anticipated load reduction. I will maintain mechanical airspeed, altimeter and VSI for redundancy. Have you completed your upgrade yet and if so any pictures to show for your efforts !!

Mapleflt

I've installed several G5's now including my own 170. It's a great unit and very accurate. The STC'd unit comes with a battery backup. I planned on getting the HSI as well but it is a little pricey. I opted to get my old DG overhauled instead. The DG is the only instrument I have still on vacuum.

"A G5 can be installed in an instrument panel that does not have an existing attitude indicator or DG/HSI. In these cases, the G5 must be located on the Pilot’s instrument panel, and centered as nearly as practicable about the vertical plane of the pilot’s forward vision. If the G5 is installed as an;
• Attitude indicator, it must be located as close to the top center position of the pilot’s instrument panel as practical.
• DG/HSI, it shall be located adjacent to and directly below the instrument in the top center position when possible."

See section 5 for installation limitations and make sure you get the latest revision as it has been updated several times since it was released. http://www.chiefaircraft.com/pdf/G5INSTALL.pdf

That is a very good looking panel, the G5 fits perfectly.
Can I ask what engine monitor you have fitted?

Thanks
Kevin

It’s the EI CGR-30P.

Mike,
Beautiful panel and radios! I’m envious! You clearly put a lot of thought into the panel layout. Curious though on the position of the G5. Would it not fit one position to the left? Also wonder where you hid the stall buzzer/light?

I originally wanted the G5 directly center but there was a clearance problem. I don’t remember if it had to do with the G5 or my electric T&B. But regardless it has never bothered me.

My radio stack is two SL40’s and a 8000BTi audio panel. I love the Bluetooth audio on the 8000. I made a custom mount for the Garmin 660. It sits flush and is removable and has a custom cover plate.

Someone before my grandfather owned the plane cut out the big holes so I wanted to fill them back in. It turned out nice and quite functional. I plan to add a Garmin 345 for ADSB soon.

The stall horn is located under the panel by the pilots left leg. No light.