VNAV->ALT

[jbeaver]

Is it possible to have the autopilot fly a VNAV profile down to an altitude and level off? When flying a practice approach recently, I set the MDA bug to 880 ft. I was then surprised to find out that I could set the ALT bug to 880 ft as well instead of the normal 100 ft increments. Naturally, I expected that there was then some way to have the autopilot fly the glideslope down to 880 ft and level off, but I couldn't figure out how to engage it.

 

[paul330]

VNAV profiles (certainly in large aircraft) are normally constructed to give you a nominal 3 degree approach.  The days of flying down to MDA and flying level to your MAP have gone - it leads to unstable approaches.

Our company procedure is to set MDA to commence the final segment of the approach and when established on the VNAV path to set MAP altitude.  At MDA, you should be in approximately the right place to complete a stabilized approach.  Then either disconnect and land or go-around - in which case your altitude bug is in the right place.

Not flying yet with the Dynon set-up so not sure if it will work like I have just described, but it's how the big boys (well, these big boys anyway) do it......

 

[Dynon]

The answer is no to the first question and paul's answer is the reason: If, when you hit your decision altitude, you don't have the runway in sight (at which point you'd continue your approach), it's nominally time to go missed, which usually means climb, not level off. When you're not following a glidepath (ie, just changing altitude via the ALT bug at the VS you command), the AP will level off at your altitude but.