Video of wake turbulence knocking a light aircraft out the sky, plus avoidance tips

[DiamondRob]

Posting here, in the DA20 forum, as the 20's are the lightest of the diamonds - with apologies if this is a repost.

I had no idea wake turbulence could turn a light aircraft upside down in under 2 seconds. The Tips given after the footage make excellent learning material. I hope this helpful video is able to keep a few more people here safe.


https://www.youtube.com/watch?v=T5XTLxoc-uU

[Rich]

Watch the scene from "Pushing Tin" for a comedic illustration of the effect.
Seriously, this is no theoretical phenomenon. It's real and it happens.

[dmloftus]

Wow, that's crazy. I'm sure everyone knows to look out for vortices after a big jet takes off or touches down in front of you. But just a low pass from a small helicopter?! Not sure I agree with the diagram shown, though. He illustrates the vortices only along the longitudinal path at the left and right extremes of the rotor blade travel. A rotor is generating lift in a 360 surrounding the helicopter so wouldn't those vortices would basically blanket the entire runway in this low pass? I'm thinking of my multiple trips in and out of KGCN. There are dozens of helicopters constantly buzzing tourists in and out for sightseeing trips to the Grand Canyon. Seems like I've never given these enough thought or consideration and I'll be more conscious of helicopters in the future. Thanks for sharing!

[mhoran]

This is super scary. Linden, my home field, is mostly a heliport that happens to have a runway. Almost all NYC area helicopters are based there, and fixed wing aircraft are seen as a nuisance. Helicopters usually sidestep over to the taxiway pretty quickly, but then hover for quite a while. I'm surprised that I've never encountered anything like this, as I've landed in similar conditions many times.

[blsewardjr]

DA20 pilots have survived helicopter wake incidents -- http://www.kathrynsreport.com/2014/01/d ... -army.html

[DiamondRob]

Wow, that's crazy. just a low pass from a small helicopter?!
Seems like I've never given these enough thought or consideration and I'll be more conscious of helicopters in the future. Thanks for sharing!

Yes! I had never stumbled upon anything which so clearly illustrated the dangers light aircraft face when operating near helicopters. Certainly worth remembering isn't it.

[DiamondRob]

DA20 pilots have survived helicopter wake incidents -- http://www.kathrynsreport.com/2014/01/d ... -army.html

The link serves as a great advisory.
Despite the crash, the text below seems crazy "Current Federal Aviation Administration (FAA) ATC guidance does not require specific wake turbulence separation criteria for a small airplane following a helicopter nor does it require a controller to give a wake turbulence advisory for a small airplane following a helicopter."

[CFIDave]

A rare DA62 crash was caused by wake turbulence: A DA62 operated by a UK company testing ground-based navaids was landing on a runway in Dubai, when -- on short final -- it got hit by a wingtip vortex generated by a wide-body Airbus A350 that had landed on a parallel (upwind) runway. The vortex drifted onto the flight path of the DA62, causing it to roll inverted right into the ground, tragically killing all 4 occupants.
https://aerossurance.com/safety-managem ... a62-dubai/

What's notable is that the landing Airbus was 3.7 miles ahead of the DA62.

[Boatguy]

A rare DA62 crash was caused by wake turbulence: A DA62 operated by a UK company testing ground-based navaids was landing on a runway in Dubai, when -- on short final -- it got hit by a wingtip vortex generated by a wide-body Airbus A350 that had landed on a parallel (upwind) runway. The vortex drifted onto the flight path of the DA62, causing it to roll inverted right into the ground, tragically killing all 4 occupants.
https://aerossurance.com/safety-managem ... a62-dubai/

What's notable is that the landing Airbus was 3.7 miles ahead of the DA62.

The 3.7nm is reported as translating to 90 seconds ahead of the DA62.

A link in the article Dave cited described a Bombarier Challenger dropping 9,000' before regaining control over the Indian Ocean when an A-380 crossed 1,000' above it. Both aircraft were at cruising speeds. This was surprising because I've always believed that wake turbulence was a problem associated with being slow.

"Caution, possible wake turbulence" from ATC is great legal cover for ATC, but it doesn't do much for us unless we take action based on that caution. I was on an instrument departure from KHWD and routed about 2,000' under a B-767 on final for KOAK. I got the caution, but I would have had to make a 180˚ turn to actually avoid the turbulence. Fortunately it was just a very sharp jolt, not a roll.

In the video, Jason suggests landing past the larger aircraft. But I think the visualization he provides is not realistic. Our light GA planes will typically land before the touchdown or aiming points. Further, the turbulence from a larger aircraft don't end when the plane touches down; it continues during some portion of the rollout, probably until the larger plane slows to less than 50kts.

As Jason points out, on departure, climbing steeper than a jet probably isn't going to happen for most of us (though Dave in his Epic can/will!).

I've typically waited one minute to TO after a departing plane, but I just upped that to two minutes. Is that enough?

[steve_falconer]

Based on this video and reading FAA Advisory Circular 90-23G my new personal minimum is 3 minutes behind a helicopter or jet. I used that this weekend flying out of Ontario (KONT) behind a UPS Heavy and two 737s when the controller asked me to advise when I was ready to depart after cautioning wake turbulence immediately after the 3rd one landed. I used my Davtron to time each of those 180 seconds before making the request.

https://www.faa.gov/documentLibrary/med ... 90-23G.pdf