Electric Trim on Arrow II

John221us

John221us

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John
I am going into pre-buy on an Arrow II and the electric trim doesn't work. The owner says the motor works, but there is something wrong with the clutch. I know it is hard to judge, but what could be the range on what it would take to fix this?
 
Anything from $100 to darn near impossible - could be a bad connection or it could be a bad servo and they don't make the servos or repair parts for the servos anymore. I've got a spare trim servo and getting me to turn it loose would probably be more than an AMU.
 
Clark1961 said:
Anything from $100 to darn near impossible - could be a bad connection or it could be a bad servo and they don't make the servos or repair parts for the servos anymore. I've got a spare trim servo and getting me to turn it loose would probably be more than an AMU.
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I thought your trim was that wheel cleverly hidden between the seats.
 
Clark1961 said:
Anything from $100 to darn near impossible - could be a bad connection or it could be a bad servo and they don't make the servos or repair parts for the servos anymore. I've got a spare trim servo and getting me to turn it loose would probably be more than an AMU.
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Ok, that could be bad. I don't mind an AMU or two, I just wasn't sure what to expect.
 
John221us said:
Ok, that could be bad. I don't mind an AMU or two, I just wasn't sure what to expect.
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Assuming the trim is Piper's and not an autopilot system, it should be repairable as long as the motor isn't shot. However, the cost could vary quite a bit based on the [correct] diagnosis. There are many ways in which the system could "not work," and I haven't found many mechanics who understand it well. In my case, the motor and switch were fine, but I had to clean up the clutch, the jackscrew (and apply the proper LubriPlate), and adjust the cable tension properly. Even if the clutch engages, it won't reliably move the system if the cable tension is off. Sometimes folks helpfully "lube" the clutch and cause it to slip. The clutch can typically be adjusted and rebuilt if necessary. I did have to buy the maintenance manual for the trim system to get it all right.


JKG
 
JGoodish said:
Assuming the trim is Piper's and not an autopilot system, it should be repairable as long as the motor isn't shot. However, the cost could vary quite a bit based on the [correct] diagnosis. There are many ways in which the system could "not work," and I haven't found many mechanics who understand it well. In my case, the motor and switch were fine, but I had to clean up the clutch, the jackscrew (and apply the proper LubriPlate), and adjust the cable tension properly. Even if the clutch engages, it won't reliably move the system if the cable tension is off. Sometimes folks helpfully "lube" the clutch and cause it to slip. The clutch can typically be adjusted and rebuilt if necessary. I did have to buy the maintenance manual for the trim system to get it all right.


JKG
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So you did it yourself? I am not sure if that is in my wheelhouse. Would this be my maintenance shop that could fix it, or an avionics shop? It has the stock Piper Autocontrol III autopilot, so assume the electric trim is stock also.
 
John, A total rebuild on my unit/including R&R was around $900 at Muncie Air in Indiana. I would expect you could find someone in your area that could do the same for about the same $$.

The first rebuild didnt fix it. the second time they did a swap of mine for a rebuilt unit on the shelf.

Hope that helps and it was a Piper variety servo.

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tmyers said:
John, A total rebuild on my unit/including R&R was around $900 at Muncie Air in Indiana. I would expect you could find someone in your area that could do the same for about the same $$.

The first rebuild didnt fix it. the second time they did a swap of mine for a rebuilt unit on the shelf.

Hope that helps and it was a Piper variety servo.

Sent from my Nexus 7 using Tapatalk
Click to expand...

Thank you Tim, that is very helpful.
 
Everskyward said:
I thought your trim was that wheel cleverly hidden between the seats.
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I understand that you're used to that majic auto-trim stuff. The 'kota has a switch on the yoke along with the wheel cleverly hidden between the seats. Of course I don't let just anyone touch the switch on the yoke...
 
Clark1961 said:
I understand that you're used to that majic auto-trim stuff. The 'kota has a switch on the yoke along with the wheel cleverly hidden between the seats. Of course I don't let just anyone touch the switch on the yoke...
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There are some good things about having manual trim. For us, no electrons = no trim.
 
I use the manual wheel in straight and level. But use the switch when I am busy

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I like everything to work. I have never had electric trim before, but if it is there, it should work.
 
John221us said:
So you did it yourself? I am not sure if that is in my wheelhouse. Would this be my maintenance shop that could fix it, or an avionics shop? It has the stock Piper Autocontrol III autopilot, so assume the electric trim is stock also.
Click to expand...

I did part of the work, the mechanic did part of the work (such as adjusting cable tension). It just depends on what's actually wrong with it.

I think that the legacy Piper factory autopilots were built by Century. My otherwise well-equipped aircraft oddly does not have one, so I just have the PET-1 system for electric trim.


JKG
 
Everskyward said:
There are some good things about having manual trim. For us, no electrons = no trim.
Click to expand...

guess I should mention that the 'kota does the majic auto-trim thing when the autopilot is engaged in either pitch or alt hold modes...it's a pretty good system for the time as the previous generation sensed cable tension to set trim in those modes...I've heard of some "interesting" failures and ya really don't wanna be on autopilot below pattern altitude
 
Well I am sure that has happened but if the clutch is set correctly you can hold it while you hit the disconnect switch. Still a good item to have

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I don't think I've ever flown an Arrow whose electric trim system was 100%. I'd just always revert back to the manual trim wheel. I've never been in a situation where it would be overwhelming.
 
You can fly mine if you want!

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it took a lot of work but the 'kota's electric trim is 100%

lot of work = everything but the wiring rebuilt/replaced
 
I was lucky I guess. No one caught it at the first annual, but the clutch had been tightened to the point that it did not slip. Adjusting the trim by hand was actually moving the servo motor which is not an easy thing to do. That was also a problem I addressed before. If the clutch is set correctly you should have no problem resisting a runaway trim with pressure on the yoke while you turn the thing off. I would not have been able to stop mine.

All of this was replaced and rebuilt but I had an intermittent problem with the servo not wanting to operate if it was cold. I could hear it trying to engage but it wasn't. That is when they just swapped for a unit off their shelf and since then all has been good.
 
Been doing some research on the PET-1 recently; keep in mind there are several different P/N for the servo depending on the aircraft SN and the installation; the servo for certain autopilot installations is referred to as the PET-1 but, as best I can tell, cannot be used by itself.

Just FYI; some "PET-1s" floating around out there cheap, but many are not advertised with the P/N.
 
Well, the pre-buy starts tomorrow. I will ask my shop about it then. I left a message for the local avionics shop, but they didn't call me back (Friday afternoon before a holiday weekend?).
 
John221us said:
I am going into pre-buy on an Arrow II and the electric trim doesn't work. The owner says the motor works, but there is something wrong with the clutch. I know it is hard to judge, but what could be the range on what it would take to fix this?
Click to expand...

Ours works but moves so slowly as to be impractical. Skip it.:no:
 
John221us said:
Well, the pre-buy starts tomorrow. I will ask my shop about it then. I left a message for the local avionics shop, but they didn't call me back (Friday afternoon before a holiday weekend?).
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A lot of shops never return calls. You literally have to show up and hang around to get an answer. It's not a normal business, they all know there is little competition and don't have to behave professionally.:mad2:
 
What part of the country you in Data?

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Datadriver said:
A lot of shops never return calls. You literally have to show up and hang around to get an answer. It's not a normal business, they all know there is little competition and don't have to behave professionally.:mad2:
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Well, that does seem to be true with avionics shops anyway :dunno:

I am going to make an effort to get it working. It sounds doable.
 
John, for you and for Data, if you have trouble finding a shop to look at it you could always contact Muncie Aviation in Muncie IN, They would probably take a core in on a rebuilt unit that your A&P could R&R for you.

They are pretty responsive, more so than most Av shops.
 
tmyers said:
John, for you and for Data, if you have trouble finding a shop to look at it you could always contact Muncie Aviation in Muncie IN, They would probably take a core in on a rebuilt unit that your A&P could R&R for you.

They are pretty responsive, more so than most Av shops.
Click to expand...


The deal is on life support after the prebuy. We found some stuff, including cracking in the support panel of the forward wing walk. I am pretty bummed.
 
tmyers said:
John, for you and for Data, if you have trouble finding a shop to look at it you could always contact Muncie Aviation in Muncie IN, They would probably take a core in on a rebuilt unit that your A&P could R&R for you.

They are pretty responsive, more so than most Av shops.
Click to expand...

Muncie has relatively good pricing too. I got the altitude chamber for the 'kota's autopilot from them for half the price Autopilot's Central wanted.
 
Friend of mine had to have the wingwalk area replaced on his Archer. Bout 3 AMU's to take care of that here in Ohio
 
tmyers said:
Friend of mine had to have the wingwalk area replaced on his Archer. Bout 3 AMU's to take care of that here in Ohio
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The deal officially fell out. My shop won't do the blind rivets against they airframe. They need to pull the wing to buck the solid rivets. Some shops do the blind rivets and it makes it cheaper, because you do not have to pull the wing. I am of the mindset of doing it right (solid rivets). Also, labor rates are a bit higher here in CA.
 
Too bad mine is so far away from you

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The problem with the electric trim going out is that the manual trim wheel requires a lot of force and turns to operate, unlike the hand crank in older Pipers and trim wheel in Cessnas.
 
tmyers said:
Friend of mine had to have the wingwalk area replaced on his Archer. Bout 3 AMU's to take care of that here in Ohio
Click to expand...

Yet another reason I don't like airplanes where you must walk on the wing to enter/exit.
 
I feel having to get on a ladder to check fuel levels makes up for it but YMMV

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