STC Question?

[Plater]

Ok folks--I've read alot about needing the Gilberti/Harer STC when converting the T-Craft BC12D-65 to a 85hp bird. But I have what I think is a unique problem. The Taylorcraft I am working on now have was upgraded way back in 1956 to a BC12D-85 (with the C85-8 engine). Hey, the year I was born!--Anyway, I bought the plane without an engine, but I do have a C-85-12F engine that I would like to install. So does the SA1-210 STC from CAP apply or do I just need to make a log book entry that I installed a new 85 hp engine? Oh, and I'm going to contiue to use the short mount with retain the orginal gross weight. Looking forward to my answers!!!!

[N96337]

Re: STC Question?

If it was mine, I'd find another -8 and hang it on and call it good. Then you've done no more than if you'd exchanged the engine for a fresh one. If you're figuring on electrics (and it CAN be done on a short mount...mine was), then you're changing things and I'd say you'll need the STC. Just my opinion.
John

[Dano"T"]

Re: STC Question?

I would hang the -12...send in a 337 stating that C85-8 engine was replaced with C85-12, weight change negligable and attach a copy of the former 85HP approval from 56' I bet it will slide right through with no issues. The records already show that that ser # was already approved for an 85HP.

[3Dreaming]

Re: STC Question?

What gross weight are trying to keep when you say the original gross weight? If you are trying to keep it so it can be operated by a sport pilot I think you need to get the FAA records for the airplane to make sure the gross weight was never increased. If it was increased your out of luck.

[Plater]

Re: STC Question?

The registration says BC12D-85. If I go to the FAA website it says for the engine catagory "C-85 Series" which leaves me to think any C-85 engine. The weight shows 1260 lbs when the engine was changed. I have the CD and I can't see anywhere that the weight was ever increased above that total. Think I'm safe with just a 337?

[Dano"T"]

Re: STC Question?

You have an easy one there. The engine "C85 Series" is already approved. Just a logbook entry and maybe a 337....I don't even know if you need a 337.

[barnstmr]

Re: STC Question?

The registration says BC12D-85. If I go to the FAA website it says for the engine catagory "C-85 Series" which leaves me to think any C-85 engine. The weight shows 1260 lbs when the engine was changed. I have the CD and I can't see anywhere that the weight was ever increased above that total. Think I'm safe with just a 337?

When you are talking about the "approved" configuration of an airplane, you are talking about its airworthiness. So, what matters is... what does your airworthiness certificate say?

[Plater]

Re: STC Question?

Hi Terry, Just looking at the Certifcate of Airworthiness posted in the plane it just gives the classification of Standard, N number and date of issuance 3/12/57. Basically an index card! As I mentioned in my first post, the conversion to the BC12D-85 was done in 1956 long before there was a Gilbert/Harer STC. Does the STC SA1-210 only apply when converting from a C-65 ??? Kind of looks that way.

[barnstmr]

Re: STC Question?

The Supplemental Type Certificate STC SA1-210 did not exist in 1956. Therefore STC SA1-210 does not apply to your aircraft. The modification might have been done 2 ways back then.

1) If the factory did the mod and re-issued the airworthiness certificate and data plate as a BC12D-85, then that means the airplane passed a conformity inspection certifying it as a model BC12D-85 under the Type Certificate.

2) Otherwise, an individual may have done the mod as a major alteration (337). In this case, the airplane would remain a BC12-D on the data plate, But it would have an approved engine installation as a major alteration.

Bottom line is that anything that has been done to the airplane that does not match the type certificate specs for its data-plate model designation has to be approved. An engine model change from -8 to -12 is considered a major alteration. Therefore you need approved data to make the change. Data can be a report, a drawing, photos and description, etc. Today, sources of approved data for this are....

- one-time field approval (requires FAA FSDO inspector signature on a 337) the FAA does not charge for this service, but may or may not take a lot of time.
- DER approval (requires FAA form 8110-3 signed by DER and referenced on the 337) my fee for this would be $250.
- STC (referenced on the 337) you could buy a copy of the STC SA1-210, but if you already have the 85 hp approved, it isnt necessary for just a change of the engine model from -8 to -12.