Altimatic II pitch trim servo solenoid

[Simon Bretel]

Hi everyone, this is my first post so treat me gently Here goes, we have a problem with our Altimatic II on our 260C, we have just bought the aircraft, and when we got it the electric trim (servo P/N PET-1) worked but the manual slipped,(not good) after some troubleshooting we found that solenoid was inop (although we have 12 volts at the terminals) and some monkey had rigged the clutch to remain engaged all the time, hence the reason the manual was slipping, I noted that the information on the side of the solenoid said it was a 24VDC and 31 ohms, however the aircraft is 12VDC, does this make sense to anyone. Also I see it's made by Guardian Electric and the P/N I can make out seems to be A420-062082-00, I have done a bit of googling and it seems this part may now be obselete, has anybody got any idea on a replacement part, and correct voltage, many thanks, Simon.

[MULEFLY]

Simon... welcome to Comanche ownership... it will be a love or your life and at a few times perhaps a bit frustrating... but those of us in this community and at the Delphi site will help you at every opportunity.

Where are you located. There are a few OUTSTANDING shops in the US to work on your AP... I took mine to Muncie Aviation... Muncie,IN... you can got back to Century too... there are a couple of other shops that are highly rated too.

All the best!
Jim

[Zach Grant L1011jock]

Altimatic II is unfortunately a boat anchor at this point. If you can patch it together, it will only be temporary. You may consider spending the money in a direction that can get you a functional autopilot for the long run.
-Zach

[David Pyle]

I think that Autopilots Central in Tulsa OK work on boat anchors. Call Barry Sparks 918 836 6418 service manager to find out.

[Simon Bretel]

Thanks for the replies guys,

I live in Guernsey, Channel Islands, UK. I am an aircraft engineer by trade, it only seems that the solenoid is U/S on our Boat Anchor II so I just need to source a replacement item to get the elec trim working, thanks for now.

[SLIMDREDGER]

Zach: I have a friend with an Altimatic IIIb in his Aztec. Apparently it will hold course and altitude with the heading bug, but is not correct in following the magenta line or glideslope. His pilot would like to replace it with a Century 2000.

John Van B is going to put an Aspen in the Aztec soon.

Is an Altimatic IIIb also a boat anchor? Or it it worth taking it to an autopilot skilled radio shop to restore the full capability?

If it were my call I think I would live with the manual control on the Altimatic IIIb and wait for the Avidyne 905 that is just coming out. It will probably be a couple of years before they get it approved for an Aztec, but I would be willing to wait as Aspen and Avidyne are currently working on combining these units to a really modern system.

Warm regards AHP

[md11flyer]

If the Altimatic 3 won't follow the needle in nav or Loc Norm mode , then what you need is another autopilot coupler.
The best way to find out if this indeed is the problem is to find someone with a spare coupler, or if he is a very good friend to take out his and install
it into your airplane.
Anyway these couplers pop up every now and again on Ebay for a few dollars.
By the way these couplers do fail after so many years... I replaced mine when it failed... very easy fix.

Good luck,
Gary

[md11flyer]

For Info:

I just looked up autopliot coupler on Ebay and there is 1 for auction at this time.
http://www.ebay.com/itm/EDO-AIRE-DG-AUT ... 500wt_1413

Cheers,

Gary

[SLIMDREDGER]

Gary: Thanks for the good help. I passed the word to my friend and think he will give it a go. AHP

[skipsouthernsky]

Dear Al,

I'm not sure, but is an Altimatic III the same as Century III ? I recently (about a year ago) had an Aspen install and part of the Aspen system is an "analog converter unit" (ACU). What that does is take the digital output of the GPS and change it to an analog output which is what the Century III responds to. It sure perked up my Century III. Don't know if this will help or not.

Until the Aspen install, all the trouble shooting on the Century III was in vain.

Sincerely,
Skip Dykema

[SLIMDREDGER]

Thanks, Skip. I have forwarded your comment on, and suggested they direct the question to Century.

I have had a Century III in my airplane for about 30 years and it has been a good unit. Recently added roll steering and I am pleased how it follows courses, holding patterns and course reversals. Wish I could use it with the glide slope following capability that the Century III has. When I try to follow an ILS with just the Century III, I miss the precise heading course following that the roll steering provides, so I usually just hand fly the approach for practice.

Warm regards, Al Powers

[skipsouthernsky]

Dear Al,

I know there are lots of ramifications to this. One of the selling points for the Aspen is it includes roll steering in the unit. As far as the ILS following goes, on my set-up, I have to turn roll steering off if following an ILS and "localizer" has to be selected on the auto pilot mode selector. The other question is what happens when using roll steering during an LPV approach? Don't know if you have that LPV capability or not. I'm using input from a GNS 480 (WASS) into the Aspen and then the autopilot hooked to the analog converter unit of the Aspen. It gets complicated and I tend to simplify the whole thing by just hand flying any approach that I shoot. I guess I don't trust the auto pilot when the chips are down and tolerances are tight. Fortunately that is a pretty rare occasion in my flying. The only time I play with the auto pilot and approaches is with an instructor flying practice approaches under the hood with VFR conditions. Believe me, that scenario is much more difficult and more of a learning experience than hand flying ever was.

For cruise, the auto pilot can do a good job of following a GPS course while the roll steering is on. It has always held heading and altitude if that was what was selected. But I think that is guided by the artificial horizon and an altitude pressure sensor along with the heading bug on the HSI. Like I say, there are a lot of complications there and it is easy to screw up one little thing on the set-up and then have the auto pilot not do exactly what you expect it to do. It is usually pilot induced error (at least in my case) or poor understanding of what controls what. Just like computers, garbage in-garbage out.

Sincerely,
Skip Dykema

[Simon Bretel]

Hi again,

I have tried emailing Guardian-Electric but for some reason, the email keeps getting sent back, I have also emailed Webco, but they have never replied, must be something to do with being the wrong side of the pond .

Any chance of one of you kind gents trying Guardian-Electric from your side, as I said previously the offending solenoid P/N is A420-062082-00 it is rated 24VDC 31 Ohms, and it is used on the PET-1 Piper pitch trim servo.

I have seen that it is now an obsolete number, but they do make a replacement,

Many thanks,

Simon

[Jerry Mazza]

Webco does not keep it's web site updated or check e-mail. It is best to call them. They are very helpful over the phone. As to the solenoid, if it is just an on/off solenoid, then any of the proper voltage and apmerage should work. I am not familar with the wywtem, but it sure seems that it should be a 12v solenoid. Have you checked the imput voltage to the solenoid to see if it is 12v?