I know that there are a number of you using the g1000 NXi's capability for creating a direct visual approach to fields with no IAPs. From the recent posts on this subject I have been able to do the basic set-up, but have been unsuccessful getting getting it to follow a virtual GP to the threshold.

I'm guessing this is due to not having a proper FAF?  What would be the recommended FAF: +800 AGL? +1000 AGL?  Does the NXi create the FAF position from the altitude input or do I need to also indicate a distance?

As far as I remember (I've been flying the FBWA320 a lot recently), it does create a rudimentary FAF approach in the flightplan and you can select APPR for it and it will activate.  

Here’s a tutorial from the tips and tricks forum. Might help you out.

 

2 hours ago, Bdub22 said:

As far as I remember (I've been flying the FBWA320 a lot recently), it does create a rudimentary FAF approach in the flightplan and you can select APPR for it and it will activate.  

Yes - that is the procedure I used, but it didn't activate.

50 minutes ago, NismoRR said:

Here’s a tutorial from the tips and tricks forum. Might help you out.

This is what I followed when I was setting this up.  It appears the information from the actual manual is identical - it doesn't go into detail as to whether the FAF can (should) be adjusted, etc.

Everything worked fine - I was inbound prior to the FAF and I activated APPR.  I got a GP indicator and she flew right through it.  The approach seemed to be way too short - less than .5 NM.  I was past the runway before I could try a reset.

10 hours ago, RandallR said:

The approach seemed to be way too short - less than .5 NM.  I was past the runway before I could try a reset.

The whole concept of VFR approach guidance is just that - intercepting an FMS generated glideslope from nominal traffic pattern altitude. It is short procedure by design!

The real unit (in the C172) creates a STRAIGHT fix roughly 3,5NM out, this is just outside where the 3 degree slope intersects with traffic pattern altitude. You can fly in VNAV to STRAIGHT fix (sometimes even level off) and from there the magenta diamond (indicating FMS generated glidepath) can be captured from below, using APPR.

The FINAL-fix is an estimate where you would roll wings level in the pattern, around 380ft AGL and 1nm from runway threshold.

RWYXX is the the runway threshold, obviously.

Thank you.  I'm guessing that I should have descended all the way to the generated FAF altitude?

I had descended to the generated straight-in fix (IF?) and then had turned to the runway using LNAV.  At that point I activated APPR.  I got a GP indicator but the diamond was below me - the next thing I knew I had overflown the entire runway.

6 hours ago, RandallR said:

Thank you.  I'm guessing that I should have descended all the way to the generated FAF altitude?

I had descended to the generated straight-in fix (IF?) and then had turned to the runway using LNAV.  At that point I activated APPR.  I got a GP indicator but the diamond was below me - the next thing I knew I had overflown the entire runway.

Correct. As said in the tutorial (!!! 😉 ) you have to set the altitude of the 'FINAL faf' waypoint as your goal. You set a higher altitude (STRGHT) and hence the plane didn't descend any further.

Also make sure you enable APPR in time! I often enable it long before I reach the faf. 

Edited March 22, 20224 yr by tup61

Just FYI,

We have some reports we're investigating that visual approaches and VTF are giving incorrect vertical guidance. So if you're doing everything right and still it seems like the guidance is putting you really low, you may be encountering this issue.

We hope to have a fix in the next patch for this.

Thanks for the update!