RNAV approach

pequenyo

Anyone managed a RNAV approach? It doesn’t do the final descent for me. Have Nav 1 activated and in theory u don’t need any frequency. FMS 1 activated. On the other hand, ILS works perfectly.

Dingle

This post is deleted!

jmarkows

The FMS is incapable of doing vertical guidance. You either need to perform it LNAV only, or for vertical guidance use the ILS or set the GNS to drive the AP and enable the approach there.

pequenyo

Could u be a little more explicit with GNS? Don’t quite follow… u mean I need to use the garmin GPS?

jmarkows

For the specifics of it you'll have to read the manual. I haven't finished it and my only time in the plane so far has been a quick startup and some controls configuration.

But the center console GNS 430 unit is not involved or interfaced with the FMS at all. The FMS itself has no vertical guidance modes, so if you're using it you'll need to do an LNAV only approach and handle the vertical guidance yourself. If you want to do an LPV approach with the faux glide slope, somewhere in the system is an option to have the GNS drive the AP and FD instead of the FMS.

pequenyo

Ok, I will take a look to the manual… (in the CDU the only 2 options are FMS or LOC)

jmarkows

Check the manual page 75 for starters.

pequenyo

Thanks. Gonna try that!

pequenyo

So, after trying several times, here my findings:

Switch immediately to GNS and not during the flight or u will have issues.
Do not introduce anything in the Garmin unit until u switch otherwise all data will be lost.
U have to introduce the FP in the Garmin unit also. Do NOT use AP transfer button or u wont be able to select GPS on the Garmin unit. (honestly I dont know what it does since I did everything without it)
The plane will fly the FP with the Garmin unit. U have to select the HDG or NAV button but NAV will obey the Garmin unit. U can use the AP for ascent and descent (vertical movement: IAS-VS-DES). Activate the Approach button on the AP and it will do the final descent.

I believe there are several bugs since I had a lot of issues.
It works, but I would say ILS is much simpler and at the moment without bugs.

Black Square

Just some very quick responses:

It should make no difference when you enable/disable the GNS.
I'm seeing reports of this. I have an idea to get around a WT limitation.
The AP transfer button is explained in the manual. It's for controlling the autopilot from the copilot's instruments.
This is the intended operation. Vertical modes are controlled by Starship, while lateral and vertical approach guidance is supplied by the GNS in NAV or APPR modes.