Avoiding Helicopters

[londonblue]

Last week I was doing a few circuits to practice my landings and was advised to keep an eye out for a helicopter hovering on the extended runway centreline (It looked like a police helicopter). It wasn't in my way at all as I was turning to stay in the circuit well before it, but it got me thinking about safe distances from helicopters. Is there a rule about how close you can get, and can you fly underneath? (I know most people may say why would you fly underneath, and I agree that I can't see any situation where I would, but, should the situation ever arise, how far below would you consider to be safe?)

[9 lives]

I would assure the same separation from a helicopter in flight, as you would any fixed wing aircraft. Other than trained and briefed formation flying, if you are even thinking of an aerodynamic concern associated with a close by aircraft, you are much too close!

[thing]

There's a CAA pink sheet about choppers. It's time for rotor wash to disperse that is the important thing rather than distance, in the same way as you wouldn't take off or approach straight after a big jet. Been a few accidents where light aircraft have been rendered uncontrollable by rotor wash, for some reason that I'm not brainy enough to understand rotor wash hangs around for a long time near the ground after a taxiing chopper has gone past. I always give them a wide berth. I don't like to be too close to them anyway as they are so ugly they render me unconscious.

[Jan Olieslagers]

Fly 1000+ AGL and you'll not see even a shadow of a chopper.

[150 Driver]

Jan, that may or may not be the case for civilian ops but I often come across military higher than that. And you don't want to tangle with an Apache !

[9 lives]

Rotor wash you might encounter from a helicopter hovering or hover taxiing is rather different than a helicopter in cruise flight. When you are in flight, avoid the helicopter as you would an airplane of the same size (don't follow it - wake turbulence). A cruise flight helicopter makes a wake similar to a plane.

If the helicopter has lifted off a runway, treat all the air from the lift off point onward (and considering the turbulent air being blown by the wind) as the lift off point of a heavy jet. You would not land in, nor fly through air in the area of rotation of a heavy jet on takeoff, so don't fly through the helicopter's wake either.

Yes, planes have crashed, because the pilot tried to fly through (even just an overshoot) the helicopter's wake, and it did not work. Think about it, if a 20,000 pound helicopter is hovering, 20,000 pounds of air is on the move around it at every moment - how much of that 20,000 pounds of air can your plane get tangled into? How much does your plane weigh?

If you are taxiing, Give it at least five rotor diameters away from the helicopter in all directions. If in doubt. stop and wait. If he flies near you, his wake is his responsibility. When I hover taxi, I give taxiing planes the widest birth I can manage - as I am usually not bound by taxiways.

[Heliport]

An old thread in the Rotorheads forum -

http://www.pprune.org/rotorheads/212675-inquest-rotorblade-downwash-did-not-cause-plane-crash.html#post2412908


There's a link to the AAIB report.

[astir 8]

But also read

Air Accidents Investigation: 1/1993 G-BPJT (http://www.aaib.gov.uk/publications/formal_reports/1_1993_g_bpjt.cfm)

which gives more detail on the dangers of helicopter downwash