We finished up the one in my 235 in two evenings, but the interior was already out for an annual. Since there were two of us on it, I would figure around 20 to 25 hours at the most of our combined time. The most time consuming parts are getting your panel apart to get to the backplate of the navigator to run the 429 connections and RS232 connections and getting all of the vacuum gauges, lines and stuff pulled out. I prewired most of the aspen connections to the Navigator, Trutrak, power for the aspen and switch on the bench ahead of time so I could get the backplate apart, pin it quickly and then place the switches, connect the new breaker and switch for the apsen and then place the RSM and make it's connections in the Aspen connector and finish assembling it. Mount the Aspen bracket and make the rectangular cutout to your panel overlay (this can be time consuming if you are cutting the old plastic as you have to really take your time, I use a small reciprocating body saw with a fine blade at slow speed and it does a very good job).
It is much easier than an engine monitor install. The Aspen jobs that take a long time are the ones that require an ACU and the goofy transformer circuits that have to be hand built to interface to an old Century autopilot. Those get to be tedious as you are working with those delicate blue amphenol connectors that fall apart in your hands and create new issues.
Without an ACU and hand built circuit the install time is much shorter. Since the Trutrak, Navigator and Aspen are all digital the connections are much quicker, much more reliable and there are not nearly as many wires.
If you add an ACU for an analog Nav/Com like a King 155 or something to input nav data to the Aspen it isn't as time consuming as the Century autopilot stuff, but will add a good bit of time.
On my Lance and on the 235 I did not bother to bring the analog devices into the Aspen and leave them connected to their original CDI which also satisfies the requirement for a backup Navigation CDI in case of failure of the Aspen. Would it be nice to have the analog units also display on the Aspen along with the digital info from the Navigator.... yes, but not for the added hours and $1000 for an ACU that I don't need otherwise since I have a digital autopilot.
I've already prewired my Lance install. I had a plastic blank over an old annunciator I pulled out from the old Apollo setup I removed last year, so I made a metal plate to fit there, put in the power switch for the aspen, the NAV/ASPEN selector switch and the breaker and pre wired it all. I will slide it into place, pull the wires to the appropriate locations, pin them out into the NAV and Aspen, hook up the power and grounds, etc... and it will cut down on a lot of time of having to have the airplane apart and in the way on the shop floor.
