Wake Turb, is it ever avoidable?
Thread Starter
Joined: Apr 2008
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From: Test
Wake Turb, is it ever avoidable?
Hi all,
A case of a B747 banking 30 deg with stall warning activated when an A380 passed above it. With the usual conditions of encountering wake turbulence being constant-low wind speed, stable atmospheric conditions, how can one ever avoid it?
With Regards.
A case of a B747 banking 30 deg with stall warning activated when an A380 passed above it. With the usual conditions of encountering wake turbulence being constant-low wind speed, stable atmospheric conditions, how can one ever avoid it?
With Regards.
Joined: Dec 2002
Posts: 2,775
Likes: 353
From: UK
There will be circumstances when wake turb cannot be avoided. Many incident encounters involve over reactions by crews. Modern autopilots are very capable for riding out attitude changes, but pilots must always expect the unexpected - keep calm don't over react.
I recall research from the 1970s - evaluating various sensors, which with other measurements identified a broad range of situations, e.g. arrival and takeoff spacing.
However, in many terminal manoeuvring areas there is insufficient airspace space for even the best detector to allow total avoidance; thus with track routing and spacing there can still be surprising encounters, but not the most intense. Thus crews must anticipate and manage.
En route, oceanic airspace etc, as discussed above; avoidance - never for certain, thus be prepared to be surprised.
Thoughts - ATC have predictive track collision avoidance; the converse, a view of past-track with descending wake might provide a means for alerting.
Similarly for ACAS; pilots should have a 3D mental plot of close traffic - what if.
'it's only a quick software change' patent applications via SP
I recall research from the 1970s - evaluating various sensors, which with other measurements identified a broad range of situations, e.g. arrival and takeoff spacing.
However, in many terminal manoeuvring areas there is insufficient airspace space for even the best detector to allow total avoidance; thus with track routing and spacing there can still be surprising encounters, but not the most intense. Thus crews must anticipate and manage.
En route, oceanic airspace etc, as discussed above; avoidance - never for certain, thus be prepared to be surprised.
Thoughts - ATC have predictive track collision avoidance; the converse, a view of past-track with descending wake might provide a means for alerting.
Similarly for ACAS; pilots should have a 3D mental plot of close traffic - what if.
'it's only a quick software change' patent applications via SP
Joined: Feb 2000
Posts: 4,706
Likes: 590
From: 500 miles from Chaikhosi, Yogistan
Speaking of which has the BFU released the report into the challenger under the 380 in the Middle East 5+ years ago?
In particular the apparent rudder inputs that were in the FDR trace in the preliminary report looked interesting.
Joined: Jul 2006
Posts: 1,100
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From: Somewhere over the rainbow
On Airbus there is no need to keeps your hand on the side stick in the cruise. Airbus Recently released and FOT about this. If you encounter wake turbulence, most pilots would be tempted to act on the control and try to fight it and would just make things worst. Airbus recommends to
- In the case of wake vortex, if the AP is disconnected, release the control and wait for a reasonable stabilization of the aircraft:
- Roll wings level
- Restore the initial cruise level or the standard climb or descent trajectory.
Joined: Feb 2000
Posts: 4,706
Likes: 590
From: 500 miles from Chaikhosi, Yogistan
Yes, Airbus did a lot of research post the challenger incident as there was a lot of mud being thrown at the A380 and its wake turbulence characteristics (unfairly as the research showed).
