Curiosity

[BettingMan]

I’m not a pilot and I just work in the industry for a dozen years. I use to flight quite frequently and as result of I’ve experienced before light to moderate turbulence for many times which in some way makes me familiar with such kind of situations. However, my last experience was a bit different of all my previous turbulence episodes. During cruise flight and apparently with clear and good weather, suddenly and unexpectedly the aircraft started to roll and yaw “smoothly” but with significant amplitude. Not a single shake or vibration, no pitching, no Gs. Just roll and yaw which led the Captain to turn on the “fast seat belts”, to command cabin crew to take their stations and provoke total silence among passengers with some of them starting to feel sick. I felt like to be seated in a boat facing crossing waves rather than in an aircraft! This situation last for about 2 to 3 minutes and occurred at approximately at 05H00 UTC over the Pacific Ocean and at around 10º North 110º East.
Is this kind of turbulence (?) frequent or “normal”?:confused:
Just for my curiosity if anyone can give a word on this I’ll appreciate it.

[sprthompson]

Was it anything like this..?

YouTube - Basset Aircraft Dutch Roll Test Pilot BBC TEST PILOT SERIES (http://www.youtube.com/watch?v=vqVQ_s8XL6s)

I'm not a pilot but i've heard of something called dutch roll (rythmic yaw and rolling combination) - don't know if that can happen to an airliner tho.

[jpoth06]

Sounds like it was Dutch Rolling.

What aircraft was it?

@sprthompson (http://www.pprune.org/members/289618-sprthompson) Airliners can Dutch Roll, although many use yaw dampers which reduce the amount of Dutch Roll (None completely get rid of it)

[BettingMan]

It was an A320

Watching into the movie it seems that something very simmilar happened. However, I think that for longer time and mainly with a much bigger magnitude.
Thanks for the information

[Akrapovic]

I'd be very surprised if you were dutch rolling in an A320.

I've had similar conditions to what you describe when sitting in someone's wake at the same level. Occasionally when you intersect the same track at an acute angle, you can end up in a situation like this for a couple of minutes until you finally escape their wake as you head off on different tracks.

The airbus autopilot system has a tendency to wallow about oh so slightly on autopilot, unlike the Boeing which is a bit more 'pinned' in making corrections to deviations in altitude.

It might not be this, but it's a possibility!