400a autopilot to Century Non-slaved HSI

[rmorris]

Originally Posted by Pete Somers

Robert
Your Avionics Guy is correct. The heading information comes from the DG on the Navomatic 400 system and you cannot hook up a external DG to this system.
The control unit is part of the 400 Navomatic system.

Pete

OK, you need to work on how you deliver bad news

Seriously, any thoughts (Pete or others) on any other options. Go out and upgrading to an STEC 50 is not really an option for me (just had to pay to replace the rear engine, and now for getting all this avioics work done, not to mention a TON of other items, all since last September).
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Avandia Heart Attack

[Pete Somers]

Robert
There is no way around this, I went thru the same thing and could not find an answer, the DG has to go back into the system, so we installed it in the right panel and piped it up to the vac.
At least you have a spare DI and you will still have to remember to reset it.

Cheers
Pete

[WebMaster]

Hmmmm. I have a slaved HSI. My autopilot is the 400, not A. It has a switch, for heading or approach. Approach works off the HSI, and heading works off the old DG. I remember flying it, tracking a VOR, and it will track a VOR. We were several miles away, so it wandered a bit, but we definitely can track a VOR, off the HSI. I think it will also fly the glidescope.

[Pete Somers]

Yes Larry you can do it that way, however the heading referance will still have to come from the old DG as this is the only compatible unit for this autopilot.
Nav can be coupled up normally with VOR/ILS coupling but but the heading reference will be from the DG.

Pete

[WebMaster]

yes, forgot that part. The heading DG is still in place, the old vacuum one, and when the autopilot is in "heading" mode, it is driven by the old DG.
Incidentally, I fly it in heading mode 99% of the time.

[Pete Somers]

Larry, if you are in Heading or Nav mode the DG still provides Heading as this is required for crosswind correction whilst on a radial or a Loc approach.
Unfortunately this is one of the older autopilots that require the whole system to be there to make it work correctly, and with upgrading the autopilot there is no way around this problem.

Cheers
Pete

[rmorris]

UPDATE:
He went ahead and put in the old DG, so it's still wired to the Navomatic 400...but since he tells me there is a bad servo, he didn't hook-up the KLN90B or KX155 to the ap (ie nav inputs).

So I'm looking at two options:
1) Source a servo for the Navomatic 400 and ask him to complete the install - which still means that I have to have my old DG for heading input, not my newly installed Century HSI
2) Find a cost effective upgrade to the Navomatic 400 instead of just replacing the servo on thois one.

All comments welcome (either here or email me at rmorris@agsi.us)

Specifically -- sources for #1? suggestions (and please keep the 'go buy a new STEC 60' to yourself, looking for other alternatives that come from experienced owners/pilots/mechanics)...maybe a way to upgrade to a newer Navomatic with minimal part changes and labor? Of course, sources for any parts suggested for #2 as well.

Thanks,
Robert
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