Landing "destabilized by the preceding aircraft"?
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Landing "destabilized by the preceding aircraft"?
Flew into Paris CDG* on Monday on an Air France A321. Following a smooth and uneventful descent in apparently calm conditions, we had crossed the airport perimeter and were above the runway - I would guess 2 or 3 seconds from touchdown, whatever height that would be - when the plane rolled abruptly to the left and seemed to be shunted sideways. It rolled back to level, descended for an instant, then the engines roared and we shot back into the sky. Wheels didn't touch, but it must have been close.
Once we'd leveled off and begun the long trek back to re-start the approach, the captain announced on the PA that we had had to go around because we had been "destabilized by the preceding aircraft". I've never heard this before. Does it mean wake turbulence? I would have thought that by the time the preceding aircraft had cleared the runway, any wake would have dissipated. Just curious, if any of the pilots here can explain.
(* I recommend against this - the airport is a complete shambles in every respect. I think I'll address that in another thread...)
Once we'd leveled off and begun the long trek back to re-start the approach, the captain announced on the PA that we had had to go around because we had been "destabilized by the preceding aircraft". I've never heard this before. Does it mean wake turbulence? I would have thought that by the time the preceding aircraft had cleared the runway, any wake would have dissipated. Just curious, if any of the pilots here can explain.
(* I recommend against this - the airport is a complete shambles in every respect. I think I'll address that in another thread...)
Join Date: May 2009
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Not a pilot, but from Wiki:
Parallel or crossing runways
During takeoff and landing, an aircraft's wake sinks toward the ground and moves laterally away from the runway when the wind is calm. A 3 to 5 knot crosswind will tend to keep the upwind side of the wake in the runway area and may cause the downwind side to drift toward another runway. Since the wingtip vortices exist at the outer edge of an airplane's wake, this can be dangerous.
Parallel or crossing runways
During takeoff and landing, an aircraft's wake sinks toward the ground and moves laterally away from the runway when the wind is calm. A 3 to 5 knot crosswind will tend to keep the upwind side of the wake in the runway area and may cause the downwind side to drift toward another runway. Since the wingtip vortices exist at the outer edge of an airplane's wake, this can be dangerous.
Paxing All Over The World
Wake turbulance indeed. the speed at which it decays depends almost entirely upon the winds at that moment. The speed and height and angle of the wind will drive the wake and that is combined with it's natural deterioration.
Also, if the wind is caught around buildings, that also causes side eddies. For example, landing at LHR on the prevailing Westerlies, there are large maintenance buildings which can divert the wind.
I can say that, in 48 years of paxing, I've never had a Go Round, so it is rare for it to be so strong but caution works best.
Also, if the wind is caught around buildings, that also causes side eddies. For example, landing at LHR on the prevailing Westerlies, there are large maintenance buildings which can divert the wind.
I can say that, in 48 years of paxing, I've never had a Go Round, so it is rare for it to be so strong but caution works best.
Here's a good visualisation of wake turbulence.
And talking of landing destabilsation - Fraport is in a clinch with residents close to the threshold of the new NW runway whose roof tiles are being picked up and distributed throughout the neighbourhood.
Report here - Google Translate it.
And talking of landing destabilsation - Fraport is in a clinch with residents close to the threshold of the new NW runway whose roof tiles are being picked up and distributed throughout the neighbourhood.
Report here - Google Translate it.
Paxing All Over The World
Thanks RevMan2, that's superb.
Gibon2, just imagine when one of those 'curly-wurly' vortices rolls back across the runway just as a smaller machine is about to touch down. And, of course, they are invisible!
Gibon2, just imagine when one of those 'curly-wurly' vortices rolls back across the runway just as a smaller machine is about to touch down. And, of course, they are invisible!
Last edited by PAXboy; 5th Oct 2016 at 13:29.
