1980 M20K Possible to convert flap switch to MSE-style 3 position?

[johncuyle]

Was talking to my IA the other day while dropping my plane off to have GAMIs installed and have CSB19-01 done.  They had a few other Mooneys in the shop, one of which was an MSE.  I asked him, "Isn't that the same as a 205?  I flew one of those once and instead of the 'Up, don't move, spring-loaded hold to move down' flap switch if had an 'Up, Takeoff, Full" switch.  That one like that?"  He said,  "Yep".  I asked him if it was possible to convert mine over, and he said that he didn't know of any legal way to do so.  

First question:  Anyone know of an STC or some other rule which would permit the upgrade.

I then asked him if it might be something that could be done under field approval.  He said "Maybe.  If you can get paperwork from someone else who has done it."

Second question:  Anyone done this and gotten field approval?  Third question:  Mind sharing the paperwork?

One of the few things I really dislike about my 231 is the design of the flap switch.  It seems to have been designed to mimic the function of the hydraulic flaps that the electric flaps replaced without any consideration being paid to improving function.  The MSE design is much better.  Apparently newer planes went back to the older design for some reason, but I've never found a need for a flap setting between takeoff and full but I've wished for the MSE three position switch every single go-around.

[M016576]

Interesting- I had no idea the MSE had a different switch.  Is it a different motor as well, or just the switch?  I’d imagine if it’s just the switch, any A&P should be able to swap it out, then document it as a “minor change.”  I cant see why that would require a full STC (unless it’s the whole motor and switch that need to be changed)... placarding maybe?

Edited April 14, 2019 by M016576

[kortopates]

It'll be MUCH more involved than a switch. If you really want it and not worried about the cost, just get a list of all the different parts from the IPC for flaps. I think its going to involve a pc board and switch, perhaps indicator up front and additional electrical parts including relays and hardware at the flap motor. With that you can price out the cost of the parts alone. I expect you'll find the cost prohibitive unless you can find most of them at a salvage yard.

The OEM doesn't need STC's, their mods are done by drawings. Mooney has likely not done a drawing for making the 3 position flap system a retrofit kit, but who knows without asking so starting with a email to mooney's tech support email could be a first step. But field approval approval shouldn't be too hard since Mooney incorporated the system in the same airframe in the J model providing it turns out the only differences are in actuating the flaps - but that's a lot of assumptions without taking a closer look.

Edited April 14, 2019 by kortopates

[M016576]

17 minutes ago, kortopates said:

It'll be MUCH more involved than a switch. If you really want it and not worried about the cost, just get a list of all the different parts from the IPC for flaps. I think its going to involve a pc board and switch, perhaps indicator up front and additional electrical parts including relays and hardware at the flap motor. With that you can price out the cost of the parts alone. I expect you'll find the cost prohibitive unless you can find most of them at a salvage yard.

The OEM doesn't need STC's, their mods are done by drawings. Mooney has likely not done a drawing for making the 3 position flap system a retrofit kit, but who knows without asking so starting with a email to mooney's tech support email could be a first step. But field approval approval shouldn't be too hard since Mooney incorporated the system in the same airframe in the J model providing it turns out the only differences are in actuating the flaps - but that's a lot of assumptions without taking a closer look.

Still surprised that mooney would go through the trouble of redesigning a system like the flap controls.  Do you think they saved weight with the “new” design?  The flap system doesn’t seem to be a failure prone area.  Maybe the limit sensor... unless there’s something I’m missing (I’m sure I am).

[larryb]

The flap position relay system is not that reliable. Lots of people (including me) have had trouble with it. Save your money.

[kortopates]

Still surprised that mooney would go through the trouble of redesigning a system like the flap controls.  Do you think they saved weight with the “new” design?  The flap system doesn’t seem to be a failure prone area.  Maybe the limit sensor... unless there’s something I’m missing (I’m sure I am).

It could only add weight. It probably add another 50% to the circuitry.

 

I assumed Mooney went this route to offer a higher Vfe speed for approach flaps. But they only did this for the

J model. They provided the same or similar 3 position flaps on all the G1000 installations without a higher Vfe.

 

 

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[amillet]

5 hours ago, larryb said:

The flap position relay system is not that reliable. Lots of people (including me) have had trouble with it. Save your money.

Ours has worked flawlessly for 21+ years 

[carusoam]

I got to about 20years and then the relay/position sensors have given some trouble...

The best part of the three position switch... it is set it and forget it.... mostly... when they work properly...

We are busy enough in the traffic pattern... holding a switch down waiting for flaps to be in place, while monitoring and adjusting trim is too un-needed...

Of course, the trim motor runs at the same deployment speed as flap motors... so there is an advantage to this Mooney system...

Amazing that the trim doesn’t automatically adjust to match the flap deployment...   (don't go too far with this idea)

 

+1 on Paul’s points regarding factory parts in factory planes...

 

+1 on Job’s fancy avatar update...

 

Best regards,

-a-