Pitch Oscillation

Arek5

Hi I found a issues with the F28-1000 where after leveling off at cruising altitude it begins to oscillate in pitch from 500fpm to -500fpm. I havent tried the other variants yet. Looks like this occurs most often at higher altitudes such as FL290 and below mach .7.

Woolies

Interesting, I just did a cruise at 30000 in the 1000 variant and had no issues.

Arek5

yea that is odd. I did a flight in the 4000 and it was fine. Not sure if it makes a difference but when i fly with the standard navigation it happens but when i use the garmin it doesnt.

Arek5

EDIT: I tested the other variants and found no issues with them. Oscillation only occurred on the 1000 version.

aw7143

@arek5 I've had it happen with the 3000 version. I have video of it but haven't edited or uploaded yet. The problem seems to be that the GNS is interfering with the AP function even though it is deselected.

Martyn

Hi all. Our flight model and autopilot developers are investigating this issue now.

Arek5

@martyn OK thank you for looking into this. A few more things I noticed about this issue. It occurs at any altitude, and at speeds below say mach .68. As you accelerate up to around mach .7 the oscillations begin to die down and ultimately fade away. I only had it happen in the 1000 and I tested all the other versions with no issues.

dadgametime

@arek5 I haven’t had this happen in the -1000, but since the F28 isn’t an RVSM capable aircraft, I never fly at FL290 or above because it’s not allowed to do that.

aw7143

Hopefully this will help the investigating:

https://youtu.be/LDw35E61Qts

taguilo

It seems to be mostly related to aircraft too light (in the video it shows 0 pax). Maybe other factors could be affecting too, like high altitude.
Would be great if you can repeat the same flight with a mid and full loaded aircraft?

Thanks!