Prop Problems

[pgrusenmeyer]

In the middle of the first annual on my 1963 M20C and I was informed the prop is not legal. This was not discovered during pre-buy inspection. I have a Lycoming O-360-A1D engine with a McCauley 2D36C14 prop. Only the McCauley 2D34C53-A is approved in the type certification - http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/cd54a24fc81bae1c86257df20054b12c/$FILE/2A3_Rev_56.pdf.

There is an unsigned, undated log entry from 1971 indicating the prop was switched out after a gear collapse and the new model installed with a 337 in the logs. No 337 to be found. No 337 in the FAA list of 337s. Prior owner has no other paperwork. (One might say the prior owner sold an un-airworthy aircraft, not permitted by the sales agreement, but may be tough to prove the 337 was not in the transferred paperwork).

A&P is trying to see if we can find a DAR (Designated Airworthiness Representative) to possibly review and certify to try to get the FAA field approval of the current prop. It has been on the aircraft for 35 years without incident and is approved for the M20B with the same engine. However I understand field approvals are nearly impossible these days, especially with the Philly FSDO.

Does anyone have a similar Mooney with this engine and prop? Do you have any approvals (337, or other) for it that you would be willing to share? Trying to establish an approval record.

Does anyone know a DAR who may be helpful.

Looks like my alternative is to purchase and install Hartzell’s 2 bladed Scimitar TOPPROP STC kit. Any other recommendations? Overhauled props do not seem to be readily available and advantages of having a new prop over an OH prop are significant although I'm open to an OH prop.

An expected variety of other issues found, many expected, but the prop is the real kicker.

Thanks,

Pat

[kerry]

I had a McCauley C14 prop on my previous m20a.  I really liked it.  Only AD was a place card.  To bad you can't use it.  I searched some time for a used AD free hartzell prop.  These props are out there but I found out that a new Top Prop would cost $1500 more than a used one so I bought a Top Prop.

[ArtVandelay]

I thought 337s had to be submitted to FAA? You can go online and order a CD with all submitted paperwork for your plane

[tony]

you don't need DAR, you need a DER to approve the Design. IMHO that's going to be a hard thing for a DER to approve without any test data.  A DAR just signs off that the article is built is per design. 

[Cody Stallings]

Let's talk about a different subject, but same topic.

Has that propeller seen the inside of a RepairStation sense 1971?

Has it had the Dyed-oil Conversion performed?

C14 an C53 are both Obsalete designs, an back in the day were not sealed propellers.

If it has not been converted, you could be looking at a Safety of flight issue, rather than a conflict

With the TCDS.

[carusoam]

Pgrusen,

What state are located in....?

Best regards,

-a-

[RobertGary1]

That's a good point. I wouldn't want to fly behind a prop if its not been opened up since the 70's. But I could also see it getting overhauled and the A&P just R&R'ing it without noticing that there was not legal basis for the install. But its worth grabbing your CD from the FAA and glancing through for possible paperwork that could have been filed.

 

Unless someone has produced data showing the prop is safe in that application I'd guess the odds are slim you'll get approval though.

 

-Robert

[pgrusenmeyer]

A couple of responses:

Teejayevans. Yes, 337s are supposed to filed with the FAA. As stated in my original post "No 337 in the FAA list of 337s." I have the full list of 337s from the FAA (now you can get them as a download PDF through an AOPA vender) and there is no 337 for the prop. Doesn't mean it wasn't filed with the FAA. Could have been lost by the FAA and not recorded. Seems unlikely though.

Cody Stallings - all good points. Yes, the prop was just rebuilt by the prior owner as part of the last annual in May 2014 to meet an AD. It has dye oil conversion. This was one issue that gave me confidence in the plane, low hours on the engine rebuild and a recently rebuilt prop. It was just the wrong prop.

Carusoam - southeast Pennsylvania outside Philly. Plane is based at New Garden airport - N57.

Pat

[pgrusenmeyer]

That's a good point. I wouldn't want to fly behind a prop if its not been opened up since the 70's. But I could also see it getting overhauled and the A&P just R&R'ing it without noticing that there was not legal basis for the install. But its worth grabbing your CD from the FAA and glancing through for possible paperwork that could have been filed.

 

Unless someone has produced data showing the prop is safe in that application I'd guess the odds are slim you'll get approval though.

 

-Robert

I'm no expert, but seems like 35 years safe operation on this airplane should count for something. Plus is it approved for the M20B, same airframe and same engine. But I don't think that is going to help me.

[Sabremech]

Hi Pat,

I think you can get this prop approved for your airplane since it is listed in the TCDS. If you're not familiar with anyone at your FSDO, look online at the FAA DER directory and locate a Powerplant DER in your area. Talk with that person explaining what you have going on and what you would like to do. Don't automatically give up if you get some resistance as the TCDS is going to be quite helpful in your case.

Good luck,

David

[N33GG]

Worst case, you buy a Scimitar prop if it is approved for your airplane, and sell your old prop for whatever you can get for it. Then you own and fly a Mooney with a Scimitar prop, which is an awesome combination IMHO. Not a bad place to be, and not the end of the world. And then, don't look back, and enjoy your Mooney!

FWIW

[cliffy]

You mentioned an undated unsigned log entry about a missing 337. The 337 in itself would not make the prop legal to install unless it quoted some other "approval" to use. Have you tried contacting the prop manufacturer to see if they have an addendum of some sort to use that prop on your airframe? It might be a long shot but it might work.

I am suspect of the unsigned log entry as it seems the swap was made and then someone found out that it couldn't be used and didn't want their name on it. Unfortunately it should have been caught on a pre-buy and at every annual since installation.

Sorry for your issue here and I hope you can get it straightened out without too much worry.

As was mentioned, you might be able to get enough for your prop to make the swap to a new one not too big a hit.

Get it back in the air and enjoy flying it. 5 years from now all this won't mean squat to you.

[Cody Stallings]

Well it's good its been O/H inside of the past 44yrs...

Field Appprovel. Not sure how that's going to workout.

The propeller is not approved for a reason. Propeller application interchangeability makes sense when your doing Vib-Stress analysis to approve the prop on as many models as possible.

I'm not %100 percent sure, but the C14 an C53 probably have different Blade Design Numbers.

So the blades will not perform in the exact same way as the blade the TCDS has approved in the C53

Just my 2 cents