Helicopter ops v Vortex Wake

[DANAIRB6ER]

I'd be interested to know how various units integrate their helicopter movements with simultaneous airliner movements with regard to Vortex wake separation.

I cannot seem to find any definite reference in any of the CAP documents, and those which are published appear to be open to personal interpretation.

If for example the heli aiming point is north of a runway, but less than 760m from the centreline do you, by the book, need to apply vortex spacing between an inbound heli and a departing airliner, or would an instruction "alight at the helispot remaining north of the runway, caution vortex wake from the departure" suffice?

I notice from the Heathrow charts that the heli aiming point is located in link 43, how does this work with respect to vortex from 09R departures?

On a related note we've been advised that a helicopter on an air taxi, or hovering is not affected by vortex wake. Can this actually be found in writing in any document?

This is my first posting to PPRUNE in the hope of generating useful debate about issues which may be obvious to many, but possibly open to interpretation by others!

More to follow.........

6ER

[niknak]

We have a good mix of fixed wing (up to B767 size) and helicopters of all sizes (Offshore, training, Police, Helimed and private - just about the whole spectrum).

Vortex wake is strictly applied to all helicopters, the same as if they were fixed wing a/c, (this is not just an Airport Authority requirement, but also from the UK CAA), so much so that if the Police or Helimed have called for start or are ready for taxy, other departures will be delayed to ensure that they're not affected.

I don't know who told you otherwise, but helicopters in the hover or air taxying are just as vunerable to vortex wake.

There is a current Eurocontrol project on the subject of vortex wake, the main thrust of which is to establish the crosswind and/or component at which vortex wake need not be applied.
The general rule of thumb in the UK Military is, (I think), if the wind is greater than 10kt and the preceeding a/c is not a "Heavy", then V/W is not applied and I think that's the sort of minima Eurocontrol are hoping to prove is safe.
Unfortunately I don't have a reference for you.

[chevvron]

Vortex Wake is about to be withdrawn as it's not ICAO compliant. The next issue of CAP 413 will change it to 'Wake Turbulence'!

[terrain safe]

Vortex Wake is about to be withdrawn as it's not ICAO compliant. The next issue of CAP 413 will change it to 'Wake Turbulence'!

Does it know? :eek:

[anotherthing]

The flip side of the coin is also relevant... the downwash generated by from decent sized helicopters in the hover should be taken into account if operating near the vicinity of the smaller fixed wing aircraft!

[DANAIRB6ER]

Thanks for the comments Niknak.

Can you confirm if all helicopters depart from the runway at your airfield, or are they permitted to lift from a helicopter aiming point or apron.

The comments regarding the vortex affecting hovering and air taxing helicopters is also interesting and confirms to me that a number of airfields have differing interpretations of how to apply the vortex wake rules to different scenarios involving helicopters.

Lets assume that a Jetranger is air taxing along a parallel taxiway which is located 700m from the runway. Would you ask the Jetranger to let down in the event of a Dash 8 (vortex category small) departing the runway as it is less than the 760m specified for vortex wake purposes from parallel runways?

Is my interpretation of the above correct?

All interesting stuff!

6ER

[timelapse]

Just RE the Heathrow bit.. At Heathrow if 27L or 09R is being used for departure then heli departures and heli arrivals to/from the aiming point have to wait 3 minutes for vortex from either runway direction (4 after an A380).

[DANAIRB6ER]

Thanks Timelapse,

I'm sorry but I'm going to have to ask the obvious question here :O

When do you get a gap of 3 minutes in your departures 09R/arrivals 27L ?

Is it a case of the helicopter holding for 20 mins or do you build in a gap for it?

Thanks again
6ER

[niknak]

Medic/Police or light Helis can lift from the aprons or the helicopter strips, heavier helis use the runway, but V/W is applied regardless. If it's an intermediate departure point, its 3 minutes, otherwise it's 2 minutes.