squawkident.

My mother arrived back to LHR today at 14:15 on board emirates departing from DBX

About two hours into the flight, the aircraft experienced some turbulence, to which the pilot announced over the intercom that the cause was due to another "aircraft close by".

This seems very strange to me as a training pilot, especially as the pilot admitted this over the intercom system.
Is this not the job of ATC and TCAS systems to keep the seperation distances enforced, or is this perfectly normal.

I understand the principles of wake turbulence and the effect it can have on other aircraft, but surely the distances between the aircraft at cruise altitude should make this effect neglible?????

This announcement did send a murmour through the cabin as im sure you can imagine, as passengers became uneasy at this announcement.

Does anybody have any thoughts on this??

Yours cordially

SI

Nov71

Wing vortices rather than jet wake? or just CAT?

canyonblue737

Despite legal seperation standards it is perfectly common to still encounter some wake turbulence in situations that make the turbulence linger longer than normal. While the bumps may have in no way endagered the flight the pilot may have felt that he should provide an explanation to the passenegers to put them at ease. Sadly the pilot should haven't tried to explain the wake turbulence because it created THE FALSE IMPRESSION amoung non-pilots and "training pilots" that it was somehow the pilots fault or ATC's fault.

I actually had something similar happen to me when I was on a flight that experienced some turbulence my fellow pilot on the PA tried to explain and ended up confusing the passenegers and one wrote a letter to complain. Another time unrelated I stated on the PA "we can continue holding here for another 5 minutes but then we will be low on fuel and have to divert." What I meant was in 5 minutes we would still have plently of fuel to go to our alternate airport but of course my foolish wording caused people to focus on the false idea of "LOW FUEL!"

So... what happened? NOTHING, it was no big deal and simply a misunderstanding. And yes... wake turbulence can be encountered at all altitudes and with legal seperation standards.

wlgarwood

I once got totally rocked (90 deg of roll left to right for two or three rotations) in a CRJ after 777 pased directly overhead. Wake hit when 777 was ten miles in front of us and 2000 ft above. I think this happens more now that everyong is on GPS supported FMS navigation. We were on airways from KJFK to KIAD.

J.O.

I've had it twice while crossing the path of a B757 at high altitude. It's a sudden jolt that lasts a very short time, but is still quite shocking to all on board. I've explained it honestly to my passengers on both occasions, mainly because you never know who might be sitting back there and telling an untruth can only make the situation worse.

SQUAWKIDENT

No relation...(see forum nick!)
Mods? Surely it shouldn't be possible to register the same nick twice!
Adam

Hold West

That and RVSM 1000' separation at altitude.

Sqwak7700

The worst encounters of wake that I've had have all occurred in criuse or the enroute phase of flight. Yes, the accuracy of GPS aggravates the situation of encountering the wake of overflying heavies. With the other ingredient, light winds, you are in for a ride.

The same scenario almost put me up-side down in an ERJ following a 767 out of JFK. Luckily our FA didn't get hurt, but both of us puckered the seat cushions way up there. More recently, I was going to LA and we had a 744 pass right overhead, 1000 feet, opposite direction. Because of GPS, our tracks were identical. I was in a 744 myself, so you think that we wouldn't have rocked as much as we did. I was the PNF on the leg, so I only suggested the strategic 1nm offset into the wind side, but the PF wasn't inclined to give the boxes a smooth ride. Sure enough, about 15 seconds after the overhead traffic passed we were rocked with a few good jolts. Very sudden and hard, considering that we were in the same type and fairly heavy.

I think the combination of high altitudes and calm conditions prior to the encounter make it all seem a little worse. If you are up in the cabin, you are just not braced for the sudden jolt since it seems perfectly smooth just prior to the encounter. That makes it all the more important to be vigilant for conditions when you are trailing heavies in criuse and during light conditions.

Not to digress, but another nasty side effect of the accuracy of GPS is mid-air collisions. If it were up to me, I would offset all my tracks by 1 nm to the right, but most pilots (being the perfectionists that we are all trained to be) cringe unless the airplane symbol is right on top of the course line. Every day there are more and more aircraft out there. With RVSM and GPS being more common, it is only a matter of time before 2 aircraft meet perfectly nose to nose in flight.

So don't any of you guys lateraly offset out there on the airways. I don't want to run into you while I'm taking my criuse nap.

nzmarty

it's squawkident. note the full stop.

scudpilot

Afternoon,

Was on a BA 777 on a flight LHR - Montreal, hit turbulence about 30 minutes before arrival, the pilot prewarned us, but also made a comment that the aircraft would "never be in any danger" thought that this was unusual, till it actually started, we we right at the back, and the guy sitting next to me was crying! Overhead lockers opened (never had this before and the stewardess said she would give it a 9 out of 10!
Apparently this part of Canada is notorious for it so I am told?

HEATHROW DIRECTOR

"This seems very strange to me as a training pilot"

I very sincerely hope that you meant "pilot under training" and that you are not some sort of instructor!! What was experienced was nothing unusual at all, as has been explained already. If you want to find out about vortex wake, stand near a runway threshold when a 757, or similar, is landing. First time I heard it I couldn't believe it - like a whip crack as it hits the ground. Certainly ensured that my application of vortex separation thereafter was generous.

kopbhoy2

I had a similar experience on a CRJ into LAX a few years back, although not as extreme as your turbulence. What seemed to me (as SLF) to be a severe situation was probably no more than 15 degrees of roll to the right, followed by an immediate correction. It certainly woke me up that morning!

Whether wake turbulence caused it is something I don't know. It occured north of KLAX over the mountains, perhaps that location may be why there was turbulence, but I'd imagine we were too high for terrain to have been a factor.

Still, it's a story to tell over a few drinks

jondc9

blueskyrich


many times at KDCA, if you go to the north end of the airport, there is a park called, gravelly point.

sitting there the planes come over your head at much less than 200'.

the sound you mentioned is a very interesting one and is different for each type of plane.

my beloved dc9/md80 gives a very nice sound, sort of a zing, with a sound you might hear in an old science fiction movie.

when humidity is high you can see the vortex slightly.

regards

jon

PS...hitting wake aloft is not unheard of...but for a "training pilot" to not know this concerns me.

to further confuse the issue, mountain wave here in the USA can be felt 700 miles downwind of major mountain ranges.

singleseater

In the cruise, the traditional wake turb is neglible from the fuse etc. it is mainly wing tip stuff. Winglets reduce it a little because they blurr the mixing boundry between hi press and low press air around the wing, but they do not do enough to stop this.

At standard atmospheric conditions, wing tip vortices desend at about 500 ft/ min. If the aircraft is 1000 above u then you have about 2 mins. At .8 that equates to about 15 mls. In RVSM airspace, you can hear a 747 go over the top of you, 1000 ft above so u sure will feel it.
The 757 is a particularly bad one, so it has its own wake classification, not based on its wieght.
Just imagine going under a 380: (:-(((

apaddyinuk

Similiar event happened to me on a Qatar Airways flight from DOH to FRA a few years ago over Turkey. The plane suddenly pitched to one side without warning and us lot down the back sent our juice trays flying. The Captain was quick to make a PA to reassure everyone and it transpired that a 747 ahead was climbing too slowly and we got too close to its wake vortex or something to that effect. The Captain later told me that this was the closest he had ever gotten!!! lol