Caution Wake Turbulence -> Emergency Landing

[okgood]

Was wake turbulence a factor in

? What do you think?

 

ASHEVILLE, North Carolina - On Saturday, December 28, 2019, a Piper PA-32RT crashed approximately one-quarter mile east of the airport as it was taking off from Runway 17, and was partially consumed by fire adjacent to the Asheville Regional Airport, Asheville, North Carolina. Thankfully, all five people on board were able to exit the plane and were not seriously injured, according to an Emergency Services spokesman.

 

The Piper took off immediately following American Airlines flight 5319. The Air Traffic Control Tower warned the Piper aircraft by saying “caution wake turbulence” for their departure following the American Airlines airplane, a Bombardier CRJ-900LR. Wake turbulence is especially hazardous in the region behind an aircraft in the takeoff or landing phases of flight. During take-off and landing, aircraft operate at high angle of attack. This flight attitude maximizes the formation of strong vortices, known as wake turbulence. In the vicinity of an airport there can be multiple aircraft, all operating at low speed and low altitude, and this provides extra risk of wake turbulence with reduced height from which to recover from any upset. Wake turbulence avoidance is therefore very important.

 

 

[kgwilson]

There are several factors related to how long and where wake turbulence occurs including wind direction & strength as well as the size of the aircraft creating it. It begins to dissipate as soon as it is created and 3 minutes is usually a safe length of time before taking off after another aircraft. I believe in certain conditions it can last longer though. The fact that the pilot was warned by ATC gives me the impression that he was taking off within this time frame.

 

 

[okgood]

The fact that the pilot was warned by ATC gives me the impression that he was taking off within this time frame.

 

I agree. When I was flying out of Austin, Texas in my little Cessna 150, 152 or 172, I would routinely depart behind 737s (and larger). I would also routinely get a "caution wake turbulence" warning from the Tower. As a result, I would always make sure I was airborne well before the point the preceding jet took off, plus ensure I was climbing faster, plus make sure I was turning slightly upwind (the opposite direction of where the wake turbulence was drifting). Even with this, one time my flight instructor and I hit what we assumed was wake turbulence because it was a really violent jolt that made both of us hit our heads on the ceiling really hard. My head hurts just remembering it again. My point, wake turbulence is not to be messed with. I'm glad no one was seriously injured and I'm looking forward to learning what the cause was, either from the PIC or the NTSB. Thanks for your comment.

 

 

[facthunter]

It's a fairly standard warning that you can probably expect any time there is any real possibility of it happening. Calm air conditions are probably the most "lingering" situation. as it doesn't move away as it will when there's a crosswind and it can take a fair while to "dissipate". Slow and heavy aircraft are the most effective at forming vortices or aircraft in steep turns or  sharp pull ups at high speed. When you do steep turns you may often cut your own slipstream. This can be quite severe and throw the plane on it's back occasionally. Its worth reviewing WAKE turbulence and thinking of prop wash and jet efflux (Mainly on the ground,)  where you are near RPT. Nev

 

 

[red750]

When you do steep turns you may often cut your own slipstream.

 

I recall that happening one BFR in a Cherokee. Felt like hitting a huge pothole. Got a fright till the instructor explained what had happened.

 

 

[facthunter]

It was considered confirmation of good level holding in a turn Take  a bow. Nev

 

 

[kasper]

I recall that happening one BFR in a Cherokee. Felt like hitting a huge pothole. Got a fright till the instructor explained what had happened.

 

And in every BFR in the UK on weightshifts you are required to do a level steep 360 turn and you HAVE to hit your wake and demo recovery from it ... in a Quantum it was benign, usually just rocking buffet, one time in a Quik it shoved me over into a spiral. 

 

In UK weightshift training it is good practice taught that you not to do more than  270deg of steep turn because you will hit a very messed up bit of air that really can mess up your wings lift and control responses.

 

 

[facthunter]

In a steep turn you already have a bit of load on the structure and when you hit swirling air it will certainly react more and your margins may be small or near non existant.. A touch of bottom rudder makes a spiral out of it and  a gust can do exactly the same thing.. Recovery action must be near instantaneous especially if height is not available to play with. Nev

 

 

[Thruster88]

Back it time I used to enjoy getting in the wake of my mates Thruster in my Thruster, get in the right spot it would take about 1/3 aileron to keep wings level. Any heavier aircraft would roll me I have no doubt.

 

 

 

 

[facthunter]

 Some of that is good advice and the smoke illustrates well what is going on.. You will note the An pulled up abruptly. That will accentuate the effect as the dynamic loading at that point is significant. More lift demanded of the wings equals more wing tip vortices, much the same as when in a steep turn.

 

     To avoid... WAIT or if there's a x- wind wait less time (if you must)  and fly upwind of the previous planes TRACK. If you fly above the previous planes path you can still avoid the disturbed air as it's below and behind. These possible situations I mention only to explain the situation and is not  a generally recommended guarantee of a universal cure all , technique.  Always exercise CAUTION.

 

       Prop wash is insignificant compared to wing tip vortices. Jet tailpipe  gas velocity is often supersonic at T/O settings so I'd give that a wide berth if it's ever likely. Nev