The International Cessna 170 Association

First of all I have tried to search on this and found some info posted by Francis Cahoon in one of my previous threads but have been unable get a response from that user related to the paperwork related to the field approval received.

Has anyone else received a field approval for these tires?

Any advise on this would be most appreciated. I don't understand this process other than someone field approves some change that does not have an STC. I don't know where to start or how to start.

Why am I do this? I ended up with a set of 26 inch tires when I bought my plane and would love to see them on my plane legally.

If someone has the patience to explain this process to me it would be much appreciated.

Thank you,
Justin

As ABI already has an STC for 26" tires it would be a lot easier to get the paperwork from them to make your installation legal than going the field approval route. Their STC does require heavy duty brakes. Give Airframes Alaska a call for further details.

n2582d wrote:As ABI already has an STC for 26" tires it would be a lot easier to get the paperwork from them to make your installation legal than going the field approval route. Their STC does require heavy duty brakes. Give Airframes Alaska a call for further details.

Gary,

Thank you for you reply but I am somewhat confused. I looked on the Airframes Alaska website and all I see are 26" airstreak and 26" Alaskan Bushwheel, not the 26" Goodyears. The curcrafters.com site states the only known STC's that exist for installation of these tires is for a Piper PA-18 Super Cub and Piper PA-12 aircraft.

Am I missing something obvious? Are the STC's for 26" tires from Airframes Alaska going to also cover the GoodYear 26" tires?

Thanks,
Justin

Justin, Sorry, I didn't look that close at the STC to see that it specified a certain brand of 26" tire. This 337 from the maintenance library may be able to help but if your time is worth anything my guess is you'll be ahead selling the GY tires and buying the ones from Alaska with the STC rather than going through the headache of getting a field approval with the FAA. Have your mechanic take this 337 to your local FSDO and ask what your chances are of getting a similar approval. Note what the FAA says at the bottom of the ABI STC:

Although installation of the larger ‘Tundra tires has an adverse effect on performance and handling qualities of the airplane, the FAA has determined these effects were not significant with regard to safety. Pilots should expect a more limited field of view during taxi, a reduced rate of climb, and a deterioration of lateral and directional stability. Tundra tires reduce the airplane’s directional stability and controllability during takeoff and landing ground rolls, increase its tendency to ground loop during takeoff and landing ground rolls, and increase its tendency to nose over during landings on paved surfaces more than during landings on gravel, grass, or other surfaces that allow the tires to skid more easily.

They didn't include lower useful load. How bad do you really need to put the 26" tires on?

Gary,

Thanks again for the valuable information. As for how bad do I need them....hmmm, 99% of the time I don't need them, so it's not really a need issue it's a want issue. Like a lot of things for that we put on our planes. Did we really need that, probably not. If I had to go out and buy them I wouldn't even be having this discussion but since I have them thought I'd like to use them. What can I say I Iike how big tires look.

I was doing pretty good until this past Friday when I seen a 170 with some 29" Bushwheels on and it got me all bothered about it again. However to spend $1500 for the heavy duty brakes and then around another $1400 a tire for the 26's or $1600 for the 29's. That is just out of my league. So was just trying to make due with what I currently own.

Thanks again,
Justin

There is no stc. You will need submit field approval. I started one last year but switched to 29" AK Bushwheels before it was returned. Send me a personnal email and i will forward what i have. Good tires that.

Justin, Did you ever get a field approval for the Goodyear 26? I just got my hands on some and would like to get whatever paperwork necessary for approval. Are you running double puck brakes? Thanks for any help you may be able to provide.