hevansrv7a
Well Known Member
For those of you who would like to learn from my mistake:
For redundancy purposes but without enough analysis I wired a Y connection from each of my two GRT EFIS screens and took the merged wire to the selector which connects EITHER the '496 OR the EFIS to the TruTrak A/P. To make a long story short, this won't work. Either have a 3-way switch or only use one EFIS for this. It's working very well now on either a single EFIS or the '496. The '496 side of the switch always did work once I got the configuration right. There was never anything wrong with the GRT except the "loose nut". I made the situation worse by failing to document (or remember) that Y connection. When GRT's people asked I kept saying, no, I don't have that. Do document your wiring! I did draw it out, just not correctly.
I had considered just giving up and using the '496 only. However, there is much virtue in using the GRT instead: (I have an SL-30 for NAV Radio).
1. Transitions from GPS or VOR enroute to LOC/ILS on the AP. Ditto for synthetic appoach.
2. Can direct the AP to follow VOR or GPS or HDG any time you like.
3. Can still use the external flight plan which is read by GRT from '496.
4. All controlling of the aircraft's path is now from the EFIS. Simpler and more capable.
5. Works as in #4 even from the primary flight display as well as map pages. Exception - you need to use map page to set OBS for the VOR.
So, now the '496 direct to A/P is my backup for a major outage of the GRT, as originally intended. Keep the greasy side down. shiny side up.
For redundancy purposes but without enough analysis I wired a Y connection from each of my two GRT EFIS screens and took the merged wire to the selector which connects EITHER the '496 OR the EFIS to the TruTrak A/P. To make a long story short, this won't work. Either have a 3-way switch or only use one EFIS for this. It's working very well now on either a single EFIS or the '496. The '496 side of the switch always did work once I got the configuration right. There was never anything wrong with the GRT except the "loose nut". I made the situation worse by failing to document (or remember) that Y connection. When GRT's people asked I kept saying, no, I don't have that. Do document your wiring! I did draw it out, just not correctly.
I had considered just giving up and using the '496 only. However, there is much virtue in using the GRT instead: (I have an SL-30 for NAV Radio).
1. Transitions from GPS or VOR enroute to LOC/ILS on the AP. Ditto for synthetic appoach.
2. Can direct the AP to follow VOR or GPS or HDG any time you like.
3. Can still use the external flight plan which is read by GRT from '496.
4. All controlling of the aircraft's path is now from the EFIS. Simpler and more capable.
5. Works as in #4 even from the primary flight display as well as map pages. Exception - you need to use map page to set OBS for the VOR.
So, now the '496 direct to A/P is my backup for a major outage of the GRT, as originally intended. Keep the greasy side down. shiny side up.
