Lebel mode on SkyView auto pilot

[barbeau]

I fly a Dynamic WT9 with double SkyView and autopilot.
Aircraft correctly trimed, pushing "level" button aircraft climb by 100 fts.
TRK/ALT and HHSI/ALT work very well with out any climb or descent. It's just pushing "level" button.
Is anybody have advices to fixe it?

 

[dynonsupport]

The level button "targets" 0 FPM, but does allow the aircraft to drift up and down. It is not altitude hold, so you may see some climb or descent. The point of LEVEL is to recover the aircraft to level in an emergency, not to be used in normal flight operations.

 

[TRCsmith]

SkyView Pilot’s User Guide - Revision P - Page 8-1
"Level Mode
The autopilot’s Level Mode (or Straight and Level Mode) will immediately "attempt" to reach zero vertical speed and a roll angle of zero. It will not attempt to fly the aircraft to any previous altitude or track and it will not respect any bug inputs. When activated, Level Mode will cause the autopilot to engage if it was not already engaged".

Sometimes I wonder if the manual wasn't read before some questions are asked.

 

[jakej]

Sometimes I wonder if the manual wasn't read before some questions are asked.

TRC

That happens too often IMO :-?

Jake J

 

[jdubner]

Sometimes I wonder if the manual wasn't read before some questions are asked.

That happens too often IMO 

Someone who writes "Lebel" in place of "Level" is obviously not a native-English speaker.  Perhaps the subtle nuances of a 190-page Pilot's User Guide and a 328-page Installation Guide are lost on him. 

It would be a kindness to cut him (and others) some slack and not dish out the snarky comments in response to a question.

I wish the Dynon moderator(s) would make this forum a more friendly place to frequent.

 

[jakej]

Joe

A "generalisation" & from my perspective (& I'm not being snarky) it's very unfair for some posters to ask questions without obviously reading the install manuals. I've said it before " if you've read the manuals but then don't understand or fully comprehend them, then that's ok" IMO
There are those of us who willingly give our time & input to help others but if some of them are going to be lazy then THAT is unfair. Who knows, they could also be distracting Dynon from doing more serious work instead of spending resources on trivial issues. Note : these are just my observations and opinions & not meant to offend, I'm just asking some to think before posting.

BTW - may 2014 be good to all of you

Jake J

 

[barbeau]

Jake
1) as Joe said, I'm not native english speaker
2) I read manual many times, but some times I certainly make translation errors
3) speaking about "level" button (not lebel!!!! sorry for that), I fully understood how it works
4) a friend of mine has an aircraft with SV and autopilot, and pushing "level" the aircraft recover level without climbing or descending
5) I made some test pushing "level" button when aircraft is perfectly leveled. Each time it climbs by 100 fts

So my question was just to know if there is a way to avoid such attitude. I'm still Dynon's client.

I apologize for my poor english.

Many thanks to Joe for his kind post.

 

[mmarien]

I always though this forum was a friendly place. Let's make an effort to keep it that way.

When in LEVEL mode my plane drifts in pitch as noted by Dynon above. Seems to me that holding level with steam gauges was always easier to do watching altitude rather than vertical speed. Is there a reason pressing the LEVEL button engages VS rather than ALT HOLD?

 

[dynonsupport]

Mmarien,

The reason that VS 0 is used, not ALT HOLD is simple. If you are in a climb, and press ALT HOLD, the altitude is captured at that moment. The plane will continue to climb as the autopilot pitches the nose down, so then the autopilot will descend back to the engaged altitude after it has "leveled" the plane. So the airplane doesn't just level out, it ends up going back down. If you were in a really nose up or down attitude, this could be significant.

This is also the same reason a roll angle of 0 is used, not a heading or track hold.

Again, LEVEL is an emergency mode, where the point is to recover the plane to a basically level situation so that the pilot can either hand fly from there or program the autopilot more specifically. It isn't meant to be something used for standard operations. If you want ALT HOLD and HEADING HOLD, you should really engage using control wheel steering.

Dynamic,
Is the 100 FPM a really steady, smooth climb, or does it just sometimes hop to 100 FPM? When the office is open again next week I can ask our autopilot designer if there is anything he can think of that could cause the target to be off slightly.

 

[barbeau]

Thanks, explanations are clear. I hope my english looks friendly.
Regarding my aircraft, it climbs by 100 fts (not less not more), each time I push level button. Doesn't matter aircraft attitude when pushing level button, even if it is perfectly leveled before.
Don't worry, it's not a big issue, but as my friend's aircraft doesn't act the same way, I just want to know if there is a way to avoid it.
Happy new year

 

[Dynon]

I don't have an immediate answer to that, but we're checking into it with our AP engineers. Remember that the AP in level mode is always targeting 0 VSI. So if there's some altitude drift as it makes adjustments to achieve and/or maintain exactly 0 vertical speed, it won't re-adjust the altitude.

 

[Dynon]

So the short answer here is that this behavior isn't unexpected. There are a variety of factors that the AP uses to ensure that the aircraft has actually leveled out, and because of that, there can be some altitude drift as the AP looks to achieve 0 VSI (even if you're already about there).