Navomatic 400A autopilot
 

Would anyone know of anyone in Europe who may be able to fix a Novomatic 400A autopilot installed on a 1978 Cessna 337 Skymaster .If so would you be able to PM me their contact details. Thank you .

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I can't answer your question but I would suggest rather than trying to repair a 43 year old piece of electronics which is based on 50 year old technology, you seriously consider upgrading to a modern autopilot. A fellow I know spent over $ 10,000 over 2 years trying to get his 400A Autopilot to work reliably and finally gave up and installed a STEC 60-2 which has worked perfectly since day 1. Fixing autopilots is not like fixing a com radio where you give the box to a tech and he fixes it. Autopilot repairs have to be approached as a whole of aircraft troubleshooting exercise. For example another friend with a King FFC 200 went through 3 shops trying to fix a pitch anomaly. Eventually the 3 rd shop found that there was nothing wrong with the autopilot, the problem was a severe under tension on the elevator control cables. When all of the control cable tensions were set up properly the autopilot worked fine.

Even if you get it working again a Navomatic 400 is still a Shyte autopilot with wobbly control and limited functionality.

If you still want to find an EU repair shop I suggest you repost this in the Private Flying forum.

You could talk to Vliegwerk Holland at Midden-Zeeland EHMZ. Vliegwerk Holland BV | Aircraft maintenance & repair
But I quite agree with @BPF's comments above.

This company can obviously repair your autopilot if at all possible. Always best to go to a specialist. They are in the US but that should not be an issue, you can probably send to them as quickly as elsewhere in the EU. I have no personal knowledge of this company. Worth giving them a call at least. Big Pistons Forever makes some good points but this company can most likely advise you and also recommend alternate strategies if required : [email protected]

Thanks guys I will contact Vliegwerk. The thing is its not a "shyte' autopilot , its has worked faultlessly for over 40 years ! Its a shame to just toss such things away when there are quite possibly a few people skilled enough in traditional avionics to fix it floating around - its just finding them.

If you've had a Navomatic working faultlessly for 40 years, very well done! That has not been my experience with them. If you can get it repaired, sure, do that. But bear in mind that avionics have crossed into a new generation (actually, I think that 40 years would be two generations). I have 30 year old King avionics which I bought brand new, and are no longer repairable - at all! So brace yourself that sometimes, a recently, or nearly working system is just not reparable any more.

A 1978 C337 is a lovely aeroplane. I think IAE were the only people in the UK who had the breakout box for working on the Cessna Autopilots? Gary Joyce would be worth a call...

Things your Shyte Navomatic 400 A can’t do even when it is working perfectly, that modern auto pilots do:

- Altitude preselect with automatic capture
​​​​​- IAS hold
- GPSS
- Pitch anticipation for level out
- Envelope protection
​​​​​​- Emergency level
- Digital servos that don’t require periodic expensive calibration
​​​​- 1/3 the installed weight
- A warranty

Personally I think you are throwing away money trying to keep 50 year old tech going. I think you are in a pay now or pay later situation and the reality is likely if you want a working auto pilot you will have to buy a new one.

Fit a GFC 500. Magic!!

You can throw bucket loads of money at any autopilot, the older they are the worse that might be, but it doesn't necessarily need to be like that. I know from experience.

I have been involved with a 50 year old autopilot that some shops wanted to replace and others were able to fix for a minute fraction of replacing it. By the way it had altitude preselect, envelope protection, and when coupled to an EFIS, GPSS.

You just need to make sure you get someone who is knowledgeable and methodical. In my opinion you need to take the aircraft to the shop and not just send the autopilot computer for testing/adjustment as the problem is quite possibly not the computer/controller.

Easy and cheap things to check on first are control cable and bridle cable tensions. Also the start up voltages for the servo can be an issue if the servos haven't been well cared for and these voltages should be checked.

Any competent shop with the right test gear should be able to check out the computer/controller relatively cheaply. The problem these days is less and less shops still have the test gear.

Once you have done the basics then you can make an informed decision on whether or not to repair or replace. In my opinion it's much better to spend a few dollars on some basic methodical troubleshooting than throwing buckets of money in an indiscriminate fashion at ad hoc repair attempts or rashly going out and buying a new autopilot.

I could do with a copy of the 400B Autopilot Manual if anyone has one.... Can spend the 177 dollars but it seems pointless if someone has a copy floating about.

Cheers,

W