Wake turbulence
 

Greetings

Air taxiing helicopters on taxiways closer than 760m to the runway- does your unit apply any wake versus departures? How about a heli holding in the hover at an intermediate holding point next to the runway with a higher wake aircraft departure? (That rotates before said holding point?) all thoughts welcomed!

Simply warn fixed wings of possible turbulence from the helicopter.

And vice versa.
Most helicopter pilots, watching a heavy go past not far away, might elect to set it on the ground rather than maintain the hover. Or the pilot might elect to take his own wake turbulence separation and depart in a way that takes him clear of the wake.

My question is specifically regarding light helicopters, think r22, operating in the hover or air taxiing adjacent a runway within 760m

To put it simply. There are no requirements for wake turbulence to be mentioned, let alone seperation provided against a light heli. Though I have long believed that more research needs to be done to establish how rotor wash affects the air and subsequently other aircraft around it. We've all seen and read about incidents where aircraft have come a cropper, even behind a light.

I had an interesting chat with a pilot of a departin P28A which was climbing out parallel to a Jetranger using the adjacent heli circuit. Apparenly he almost lost all authority over the aircraft.

Seems no-one is actually understanding the question.

I don't believe there is a requirement to provide separation. ICAO blithely seems to assume that taxiing aircraft are immune to wake, even if that taxiing takes the form of an airborne (IGE, low speed) manouever.

As I inferred above, warn the pilot of the light helicopter. He/she would hopefully set it down while waiting.

Tarq57- correct and correct. I think your suggestion is pragmatic. I've trawled documents for guidance and there seems to be very little. There is mention of a helicopter crossing an active runway to be treated as an intermediate departure from that point, but no mention of said helicopter sat in the hover at a holding point whilst myriad or aircraft happily rotate before it. Are helis in the hover less vulnerable? Would you line up the heli straight after the departure, from the intermediate point and therefore into the wake, and have it wait for 3/4 mins for wake? Seems odd. My understanding is clearly off

No, I wouldn't.
I don't actually know if a helicopter in a low hover is more or less susceptible to wake from a heavy. I can't imagine it would be less susceptible, but at least it's not so far to fall.

I'd wait the full three minutes before lining it up, unless the pilot requested a waiver. That happens at my aerodrome quite a lot.

Cottam,

Our Heli aiming point is 250m from the edge of a nominal Code E runway, and is considered vortex independent from that runway, unless it's being used by an A380 (then 3 mins applies).

The taxiway some helicopters use to get to the HAP is only about 200m from the runway, but as we have been using it for hover taxying for years and years without incident, CAA were happy for us to continue using it as such. No wake separation is provided.

I apologise I did misunderstand / misread the question. Where I work is quite a small airfield and no helicopter area is "wake" seperated from any runway and as such, any helicopters carrying out training within these areas are instructed to hold on the ground should an aircraft of a higher wake turbulence cat depart / go-around on the active runway.

The same goes for heli's hovering and awaiting a departure clearance.

I haven't touched helicopter procedures since my original training but IIRC they're all to be treated as mediums for wake separation?

Guidance is scant in this regard; and unless authorised otherwise in unit MATs Part2 I would say, and we adopt, the only clear guidance which is the parallel runway 760m rule. Thus heavy landing all rotatories on the ground by 4 no later than 2 nm from touchdown and 2 mins for a dep. Caveat a departure crossing at a point before the nose wheel leaves the ground (no vortex) would be an acceptable alternate means of compliance.

Anecdotally I'm told that when a CH47 does a low approach and go-around and Gloucester the aerodrome effectively grinds to a halt for 3 mins.

With 2 relatively recent events of helicopters blowing over light GA aircraft it's a brave controller that doesn't treat wake turbulence TO helicopters and FROM helicopters with due regard.

Fred

So you have a P28A landing with a Puma hovering 100 m from the runway edge and you think that's acceptable ??

I once had a helicopter blowing onto the active because he was unable to stop it due strong tailwind. If he tried harder he would've chopped up the pavement on the taxiway with the tail rotor.

We are the 2nd busiest 'heli airport' in the uk and we apply wake turbulence to all lower category heli's air taxiing to the runway if a higher wake cat aircraft is using the runway. No part of the airport is more than 760m away from the runway so it sits on the ground for the required time. There is very little guidance in any publications so we go for the safest option.

The guidance is between aircrafts departing, landing and making a low/missed approach opposite (oddly enough there's none stated if an aircraft is making a low/missed approach same direction) and an taxiing helicopter isn't departing og landing.

BUT that said, if we feel aircrafts will otherwise be affected by wakes, we have to inform them.

However, not all pilots will request hover taxi, so you don't know if they are airborne or not.

worrying how many people seem to have a different take on something that should be nailed down in the 493 (but clearly isn't).

As a matter of interest, does this feature in your MATS 2 or is it something that people just do?

No need, it is our interpretation of the MATS PT1