Glide Path indication with new GTN750 and legacy Bendix HSI

[swish]

Hi,

to enable RNAV LPV Approaches in our M20M we want to Upgrade a GNS530 non WAAS to a GTN750.

I guess we have a Bendix KI 525A HSI (need to check), which is analog and receiving ILS and course deviation from GNS530, just no vertical guidance on GPS approaches. Is it possible to connect the GTN 750 to do LPV approaches?

We want to delay working on the pilot side of the cockpit and the KI 150 autopilot for now to go for G500Txi successor in a few years (but considering dual GI 275 now), but still do LPV approaches for CB-IR training. The GTN outputs digital signal, so it seems not possible to connect it directly to the HSI. Question is would it work via a GAD 42/43e digital to analog converter?

We have a shop that says it is possible to fly RNAV LPV approaches just adding the GTN, but not sure they understood we mean also with glide slope to 200 ft.

 

Best,

Swish

 

Edited June 8 by swish

[IvanP]

Yes. GTN 750 works with KI 252 HSI for LPV GPS approaches. I have this setup in my Bravo and it works well. The glidelsope indicator behaves the same way for LPV GPS approach as in ILS.  In fact, the GTN 750 can output vertical guidance on the HSI for visual approach as well if you want. I do not know what interface the setup uses betwhee teh GTN and KI, it came with the plane when I bought it couple years ago, but I can attest that it works. Teh GTN will also drive the KFC 150 for coupled approaches with lateral and vertical guidance.  

[swish]

23 hours ago, IvanP said:

Yes. GTN 750 works with KI 252 HSI for LPV GPS approaches. I have this setup in my Bravo and it works well. The glidelsope indicator behaves the same way for LPV GPS approach as in ILS.  In fact, the GTN 750 can output vertical guidance on the HSI for visual approach as well if you want. I do not know what interface the setup uses betwhee teh GTN and KI, it came with the plane when I bought it couple years ago, but I can attest that it works. Teh GTN will also drive the KFC 150 for coupled approaches with lateral and vertical guidance.  

Thanks for the fast reply, we made the decision today to go for it with the shop. Looking forward towards the upgrade.

[201Mooniac]

Here is the interconnect drawing for the GTN to the KI 525A, it clearly shows both the lateral and vertical interconnects and flags.

BK HSI.pdf