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APS4A altitude preselect system

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Hey folks, I have switched autopilots from an STEC55 to a KFC225 so that means I can't use this anymore, because the 225 has integral preselect.

It was in my Commander for about 2 years and 200 hours.

http://www.avionik.de/en/avionics/avsr-products/aps4a.html

Summary:

For the listed compatible autopilots it will provide altitude preselect capability with the caveats of...

1) It requires an altitude bug with an annunciation output so... Aspen or G500/600 or similar is the most common application. At minimum, an altimeter with a bug and an annunciation attached to the bug.

2) It requires cutting a hole in the panel for the arm/disarm switch. The switch is included. It's a square Eaton #96182 push-button type switch.

3) This is a 28v model.

How it works:

The manner in which you climb or descend is still controlled by the autopilot head unit, whether that be setting pitch or setting vertical speed or whatever. The way you do that in your airplane with your autopilot stays the same.

When the altitude set on the bug is reached and the annunciation fires on the G500/600 or Aspen panel, this box senses the annunciation and triggers alt hold mode on the autopilot head unit. After it does so the unit is automatically disarmed and doesn't do anything else unless you arm it again.

The result of this is a very simple and effective pre-select system. You can engage the system in any order of button presses that you like. Personally, when I was using this I started the climb or descent right away with vertical speed control after I got cleared higher or lower by ATC, then after the airplane was doing its thing I programmed the bug and armed the alt capture after the fact. If you prefer to do it the other way around and set the bug + arm first and then start the climb or descent afterward, go ahead, it doesn't care.

The flexibility of being able to program your climbs/descents in any order you like is what makes this the best preselect system I've used.

Pics here

The retail on this was 1750 dollars ($1200 for the box and Dallas Avionics is the only supplier of the switch, which they charge $550 for).

Looking for 1200.
 
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