If anyone is interested in seeing an installation of the BFGoodrich AIM520 series 2" attitude indicator as a backup attitude indicator should take a look at the March 2001 issue of Flying Magazine in an article on the new Piper Meridian.
There is a photograph of the panel on pages 66 and 67 which shows a BFGoodrich AIM520 series attitude indicator with a three position switch just above it. The switch is labeled “sdby gyro” and has “test” “off” and “on” positions. According to the photo caption on page 69 the pod under the right wing contains the weather radar antenna and the “battery for the backup attitude gyro”.
The BFGoodrich AIM520 can be mounted with the flange either behind or in front of the panel. On the Meridian, they have mounted it with the flange in front of the panel. On the Cirrus, you would want to mount it with the flange behind the panel to match the other instruments.
My plan is to mount the AIM520 in place of the Davtron clock, o.a.t. and voltmeter. The o.a.t. and voltmeter functions would be replaced by an Insight air data computer that I mentioned in prior post.
In the production SR22, the STec selector alerter is mounted above the altimeter. There is space for two additional units of the same 1/2 3" ATI size, one above the main attitude indicator and one above the airspeed indicator.
In one of these spaces I would mount a Trimble radar altimeter, above the main attitude indicator. In the second such space I would mount the Insight air data computer, above the airspeed indicator.
Doing this would require that Cirrus mount the the 6 light annunciator unit to the bottom of the glareshield, either above the flight instruments or above the Arnav display.
There will probably be resistance on the part of Cirrus to offering the air data computer and radar altimeter as options to the SR22.
It would be my hope, however, that at least that the metal work on the panel could be done. This would mean that the aircraft as delivered would have the 6 light annunciator unit mounted below the glareshield, the STec selector/alerter mounted above the altimeter as it is now, and that there be two blank 1/2 3" ATI spaces above the attitude indicator and the airspeed indicator.
With the metal work done according to the specs for the Trimble radar altimter and the Insight ari data computer, finishing the avionics would be much simpler. The aircraft would still need to be delivered with the Davtron clock, o.a.t. and voltmeter unit at the top left of the panel, but this could be switched out for the BFGoodrich standby attitude indicator without too great difficulty, since they are both standard 2" instruments.
All that this leaves is the clock. My original thought that the Garmin transponder functions included a clock is incorrect. The new Garmin transponder has count down and count up timers and a flight duration timer, but no clock. There may be room for a small aircraft clock on the right side of the right panel, or elsewhere. The clock is a required instrument for IFR flight.
It is a little early for specific panel discussions with Cirrus for me, as my position is #144 for the SR22. Does anybody have any experience with Cirrus regading panel modifications to the SR22 as yet?