The International Cessna^® 170 Association

STC SA421CE stipulates "LANDPLANE" only for the 180HP with constant speed prop conversion. Would anyone have paper work allowing this conversion on the 170B with floats?
Thanks,
Dwyer

As I recall, Bush, Avcon and Doyn conversions are very similar if not an exact match or maybe were renamed after a sale of the STC's. Maybe the Avcon guys can help you out.

The Del-Air has some major structural requirement differences that would disqualify it's paperwork for references to your seaplane application.

Also there may be a chance that later Doyn paperwork might include seaplanes due to a further "refinement" to that specific STC. There again maybe the Doyn guys can help you out with that avenue.

If it becomes necessary for you to obtain a "Field Approval" by comparison of Doyn vs Avcon blue prints could work for you if you have a good A/I PMI.

Minton,
There are a good number of these conversions which are designated "Landplane Only". I know there are quite a few of these conversions (Avcon, Doyn and Bush) on 170's flying floats. If anyone would have an airplane flight manual supplement or some other form of paper work which allowed this conversion for seaplanes, I would appreciate a copy.
Thanks,
Dwyer

Hello,
Please see the attachments to clarify the issue of "LANDPLANE ONLY" attached to STC SA421CE. This information came from Jeff J of the FAA. He does not mind sharing this information to all members of the 170 Association and having it the Association library.
Hope this helps all you fellows with this conversion and who were wondering about the "LANPLANE ONLY" issue on the STC.
Finally flying on floats!
Dwyer

Very interesting. Good on you that your airplane is not restricted. I'll probably copy these documents to our library. Thanks

The only Doyn conversion I've ever seen used the Lycoming O-340 engine of about 160HP. Is yours an o-340 or an o-360? Perhaps they never tried to certify the O-340 for seaplane use.

I have a 1955 170B with the O-360 A1A and the constant speed prop
Dwyer

Dwyer wrote:I have a 1955 170B with the O-360 A1A and the constant speed prop
Dwyer

What stc did you use to do this? Are you happy with it? Thanks Ron Smith