Chopper wake is a worry.

[Garfly]

 

 

 

 

[facthunter]

Why would one expect it not to be?   So is jet blast behind taxiing planes, especially as they are commencing taxi.  Nev

[Garfly]

14 minutes ago, facthunter said:

Why would one expect it not to be?  

Expecting a chopper to do that to me at that distance?  I, for one, would not have done. 

Post video viewing I'm a bit wiser though. Hoping others might be too.

 

 

 

 

 

Edited July 11, 2022 by Garfly

[facthunter]

A sea breeze coming through or a twister will too. A helicopter can't fly without pushing a lot of air around. Pilots have to be alert for this kind of stuff. Nev

[rgmwa]

Makes me think back to a takeoff I once did in a C152 as a solo student doing circuits. I had just started my takeoff run when a yellow rescue helicopter on an emergency call lifted off and crossed the runway climbing left to right about two thirds of the way down the strip, cutting across other aircraft in the circuit as it left the area.  I continued my takeoff not even thinking about wake turbulence and fortunately without incident, other than being surprised by the sudden appearance of the helicopter crossing my path. Must have been lucky enough to have either passed under or climbed over the wake by the time I reached the spot. We have Ericson Aircranes and other fire fighting helicopters based at out airfield every summer, and we're repeatedly warned about wake turbulence when they are operating. 

[spacesailor]

At the Oaks we had the ' police  helicopter ' practicing takeoff / landing, on the adjacent old runway. 

We never though about the rotor-wash affecting us, as it,s just like the cross wind coming between the hangers.

would that have been good for ' crosswind ' training? .

spacesailor

[facthunter]

I personally would not  think so. They are not really the same. On the approach you constantly assess the crosswind and you and your planes ability to cope with it. Nev

[bushcaddy105]

It was very timely seeing this video today. This afternoon I was about to push the BushCaddy into the hangar when a friend phoned me for advice. While on the phone our state rescue chopper (Huey derivative) passed overhead and then looped back to land at the Jet A1 pump about 25 metres away. Didn't think about this until I saw the wing start to lift, but thought really quickly then! I ran to catch the wingtip just within reach overhead and my feet briefly left the ground until I arrested the lift. By then the chopper had touched down and had the rotors feathered. This occurred from the rotor downwash only, possibly concentrated by the hangar doors behind me. What could have happened if I wasn't close? 

[RossK]

17 hours ago, bushcaddy105 said:

 What could have happened if I wasn't close? 

.......and people looked at me as if I was stupid when I tied my plane down at a Tyabb event -  there was a Chapper parked 30m away that I could see was going to be doing engine runs. By the time I got back, the chopper was gone and the Sportstar was still there, where I had tied it down.

[Yenn]

Wherever you have choppers you also have chopper pilots and my opinion of them is that they act as if the rules don't apply to them. They have absolutely no regard for the safety of others. Having said that, there are a few good ones.

[RossK]

Interestingly, Tyabb have just banned Helos from hover taxiing to the Avgas bowser.

[Garfly]

Below is the French (BEA) video (in English) that was referred to by Juan Browne in the video above.

 

The presenter makes the point that whilst the danger of chopper downwash near the ground is well understood by most pilots

the hazards of rotor wake at large distances and long periods (greater than comparable fixed wing craft) is not well understood. 

 

 

 

 

 

The video's take away message for chopper and ultra-light pilots respectively is:

 

 

Edited July 13, 2022 by Garfly

[Ironpot]

Advice on Helis -  page 6/7

 

https://www.casa.gov.au/sites/default/files/2021-08/advisory-circular-91-16-wake-turbulence.pdf

[Garfly]

Anyway, for me it means being way more wary of chopper wake and downwash than I was before.

All the more after finding this AAIB (UK) report of a Cherokee getting spun in by a Sikorsky's vortices.

 

https://assets.publishing.service.gov.uk/media/5422f94de5274a13140006ed/1-1993_G-BPJT.pdf

 

Excerpt (click image for higher rez):

 

1-1993_G-BPJT.pdf

 

 

 

 

 

Edited July 13, 2022 by Garfly

[APenNameAndThatA]

I was surprised that the aircraft hit the wake turbulence when it was at the same altitude as the helicopter. 

[Garfly]

 

Here's Jason Miller on the same incident: 

 

 

[kgwilson]

The wake turbulence from the helicopter was already almost as low is it could go as it was so close to the ground so that is why the Cessna pilot flew through it at almost the same altitude as the helicopter but that was only 20 seconds beforehand.

 

It can continue for at least 3 minutes after it is generated but begins to decay from the time it is generated. At RPT controlled airports there is usually  a 3 minute takeoff separation to avoid wake turbulence and especially if a small aircraft is following a large one.

 

If you do a perfect rate 1, 2 minute 360 degree turn you will fly through your own wake turbulence.

[Garfly]

 

Yeah, and as they say in this BEA (ATSB French style) video the slower a chopper is moving the more dangerous its wake.

 

https://www.youtube.com/watch?v=iHqN7PQraMs&t=4s

 

[facthunter]

Pretty good Vid. The person in the plane applied top rudder and I hope full power. Looked awful How quickly it dissipates depends on a few factors. Still air is the worst. Vortices grow to a bigger diameter further behind the Plane causing them with time, but the severity of the effect diminishes. Your plane will be carried with the moving air or part of it causing attitude and height changes and airframe forces and airspeed fluctuations. Nev

[walrus]

Thank you for publishing this……  I didn’t realise this was even an  issue.  I sometimes share a strip with an S61 but was not aware of the dangers.

[facthunter]

Some people insist that what happens behind the wing can have nothing to do with lift but if air is not deflected (Pushed downwards) there is no reaction to provide the necessary lift to maintain flight. Nev

[onetrack]

It's interesting to note, that even normally good reference sources, still fail to mention the dangerous vortex risk posed by helicopters. They appear to concentrate on the risk posed by heavy aircraft.

 

https://www.skybrary.aero/articles/wake-vortex-turbulence#:~:text=Vortices typically persist for between,the lower air density there.

[RossK]

We have earth repelling machines at lilydale, and I was given warnings during my instruction about their wake turbulence.

You have to be well aware of their flight characteristics, slower in the circuit and generally do a steep approach on final.

And then they hover taxi - ie they're flying in places you don't expect aircraft to be flying!

[marshallarts]

This is interesting.  I recall way back in the 1990s when I was flying my old Debonair, that during a landing at Jandakot in very benign conditions the right wing lifted and I couldn't get it to go down again despite large aileron deflection.  The Deb was starting to aim for the runway edge so I hit the power and went around, and landed without further incident.  I recalled after this that a chopper had been operating at low level on the grassed area adjacent to the runway, and I wondered if that was a factor.  I believed this incident may have led to the breakage of the left landing gear pushrod that I described in a recent post.  In fact I seem to remember making that case in an insurance claim, and the insurer paid for the repair, bless 'em.  Them wuz the days.

[facthunter]

Were you using Aviation Underwriters? Nev