The paperwork of it - Converting a Mooney to fixed gear?

[MarkH]

I have been reading out about the Mooney M20D being sold as a trainer that "graduates" to a complex aircraft.

I'm curious what impact this would have on the possibilities of "Walking Back" the upgrades?
For example if one has a complex M20D, I presume that the prop could be converted to fixed pitch and the gear fixed in place (presuming one can get the parts). Am I correct in presuming that this could conform to the TC (and would just be a log entry/A&P sign off)?

To extend this, since the M20C is based on the same TC (and a near identical airframe), so could a M20C be converted to fixed gear based on the M20D? Could the data from the TC be used for a field approval or STC?

Last, could this be done with a newer, long body M20 like the F or J?

No, I am not looking to make a fixed gear, fixed prop Ovation, but it seems the more I read about how type certificates, field approvals and STCs work, the less I understand about what the FAA actually wants.

 

[MooneyDriver78]

I undid a couple of STCs (gap seals), just required a signature.

 

[Bell206]

the less I understand about what the FAA actually wants.

If I recall, this was a factory modification. Manfacturers can do anything they want to their aircraft. No STC, field approvals, etc needed. Same with factory bulletins as those are considered part of the aircraft specifications.

Now if you wanted to modify an aircraft and Mooney didnt offer a bulletin to do so, then you would need an STC, etc. to do so.

I undid a couple of STCs (gap seals), just required a signature.

FYI: depends on the STC. Technically, if the STC is considered a major alteration and there are no restoration instructions (AP sign off only) listed in the STC then it will require a second 337 and in some cases new appoved data.

 

[Magman]

I did get involved with Mooney’s of that era. IIRC the concept was a student could learn in their fixed gear aircraft. When ready they would have the conversion to retractable done by their local Mooney Dealer or Service Center.

I did not do any of these conversions but I think the biggest change was adding the
Retraction/extension linkage. The Mooney IPCs should tell the tale though. Converting a C to a D should not be an issue if done per IPCs. I agree with Bell in that other models would require an STC or Field Approval. Maybe a DER?

Flying a given aircraft Gear-Down would need more power. A common complaint with D pilots was high oil temp. Flying slower puts less air through the Oil Cooler and through the Cylinder Cooling Fins. Rather than address these issues most folks chose to go retract.

It was around that time the Rockwell Commander 112, 112TC and 114 debuted.
The fixed gear 111 was left on the Drawing Board. Aircraft tend to be designed to fulfill a mission.

OP sounds like a good candidate for an Archer.

 

[mondtster]

I'm curious what impact this would have on the possibilities of "Walking Back" the upgrades?
For example if one has a complex M20D, I presume that the prop could be converted to fixed pitch and the gear fixed in place (presuming one can get the parts). Am I correct in presuming that this could conform to the TC (and would just be a log entry/A&P sign off)?

The fixed gear, fixed pitch propeller configuration of an M20D is approved so yes, you should be able to reconfigure it that way based on the manufacturer's documentation.

To extend this, since the M20C is based on the same TC (and a near identical airframe), so could a M20C be converted to fixed gear based on the M20D? Could the data from the TC be used for a field approval or STC?

The TCDS lists the serial numbers eligible to be an M20D so I have my doubts that you'd get someone to buy off on converting an M20C into an M20D without further approval.

Last, could this be done with a newer, long body M20 like the F or J?

Same as above.

it seems the more I read about how type certificates, field approvals and STCs work, the less I understand about what the FAA actually wants.

The FAA wants type certified aircraft to be in some sort of an approved configuration and safe for flight. In the basic sense, that's what is being determined at annual inspection time. How you get it there is another story. Some aircraft are much easier to convert into something they originally weren't than others. Likewise, some converted aircraft also have a much better paperwork trail than others. I deal with a lot of tube and fabric Pipers (mostly PA18s) which can come in a lot of different configurations and it seems like almost all of them have gotten some alteration that is either poorly documented or not correct for the configuration it is in. In my opinion a person who is going to mess around with conversions needs to be very aware of what needs to be changed and how to properly document it. That can also extend to simply buying a converted aircraft as well - the prospective owner and/or the individual performing a PPI on the aircraft needs to know what they're looking at.

 

[Pilawt]

Last I heard there was only one fixed-gear M20D still flying. It also had a fixed-pitch prop.

 

[Magman]

Wondered why someone would want to convert a Ranger to a Master and also consider the same for a Super/Chaparral.

Now one reason is obvious . The Insurance Company.
They are very reluctant to insure you in complex aircraft if low time or older than their magic number.

Cherokees and 172s have tripled in price while some higher performance aircraft are stagnant.

Many Cessna 337s can convert to 336s?

Would this logic hold with a 1 engine Apache?

 

[MarkH]

The fixed gear, fixed pitch propeller configuration of an M20D is approved so yes, you should be able to reconfigure it that way based on the manufacturer's documentation.



The TCDS lists the serial numbers eligible to be an M20D so I have my doubts that you'd get someone to buy off on converting an M20C into an M20D without further approval.



Same as above.



The FAA wants type certified aircraft to be in some sort of an approved configuration and safe for flight. In the basic sense, that's what is being determined at annual inspection time. How you get it there is another story. Some aircraft are much easier to convert into something they originally weren't than others. Likewise, some converted aircraft also have a much better paperwork trail than others. I deal with a lot of tube and fabric Pipers (mostly PA18s) which can come in a lot of different configurations and it seems like almost all of them have gotten some alteration that is either poorly documented or not correct for the configuration it is in. In my opinion a person who is going to mess around with conversions needs to be very aware of what needs to be changed and how to properly document it. That can also extend to simply buying a converted aircraft as well - the prospective owner and/or the individual performing a PPI on the aircraft needs to know what they're looking at.

Shopping for older planes I see that quite often. Explaining to someone that something needs an STC or Field Approval that is not on a plane’s records after the owner has been flying this plane for years is tough. And I am hesitant to point it out because I am not an expert.

For example, with Luscombes, there is no approved configuration that has both a fuse tank and a wing tank. But there are multiple planes flying like that (for example there is a nice red one on Trade-a-plane right now). The planes are only legal if they have a field approval explicitly for the tank configuration (the one on TAP does), but I have communicated with 2 sellers that had that config but could not show a field approval.

My knee jerk reaction is to try to stay away from planes with questionable paperwork, I just want to understand it better so I can recognize a minor paperwork issue vs a major one.

 

[Bell206]

My knee jerk reaction is to try to stay away from planes with questionable paperwork, I just want to understand it better so I can recognize a minor paperwork issue vs a major one.

One point to keep in mind is older aircraft were maintained under a different system. Some mods, which may actually look suspect under todays rules are legit. Just remember if there is a OEM drawing or bulletin its considered part of the aircraft specification which does not meet the definition of a major alteration, i.e, doesnt require a 337/field approval.

 

[steingar]

Last I heard there was only one fixed-gear M20D still flying. It also had a fixed-pitch prop.

View attachment 112426

There are three still on the register.