A319 roll oscillation
 

Apologies if this has already been covered...

Took my first (passenger) ride in A319.

Couldn't help but notice that in the cruise the wings were gently banking left and right only very slightly but noticeably, cycle was every 3-4 seconds I guess. The sun was rising and you could easily see the shadow moving in the cabin.

What's that about? Never noticed it on any Boeing before. Wondered if there was a specific reason? And is it an Airbus 'thing' or just the A319 that's affected?

Cheers Andy

Seems to happen in the 319s quite a lot. Don't know why, just happens!

Called 'Dutch Rolling'.

Don't know why the Dutch are blamed.

Often a pilot may know when to put in a touch of rudder to disrupt the oscillation for a while but it is a natural effect of the existing stabilities and the interactions between yaw and roll. A small disturbence will set it all going again.

A simple fix may be to increase the sensitivity of the yaw damper providing this did not have detracting effects elsewhere.

I've heard two explanations for this. One is that it resembles the motion of a skater on a frozen Dutch canal. The other is that it resembles the motion of a particular type of round-bottomed Dutch sailing ship on choppy seas. The former is the most commonly given explanation, although personally I prefer the latter.

G

I thought it was something to do with drunkeness, like 'Dutch Courage'. I was under the impression that Dutch Roll was a more obvious wallow, rather than just banking. I also thought it was designed out of modern aircraft :confused: .

I don't know though - i'm only a student!

Ginger ;)

My guess is that the yaw damper part of the AFCS isn't tuned exactly right. You can see this in various ways on lots of aircraft - look at the wingtip, and if it's moving back and forth every so slightly, or rolling, then the yaw damper isn't working correctly.
The yaw damper is put in to correct / stop Dutch roll, and if it's slightly out, the result will be a small (hopefully) oscillation in either yaw or roll.