Helicopter Vortex wake.???
Thread Starter
Joined: Dec 2000
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From: uk
Helicopter Vortex wake.???
Just out of interest, has anyone who flies light singles, ever experienced vortex wake when landing behind a medium twin helicopter?
Hypothetical situation:-
2 medium twin helicopters landing one after another with about 4 miles spacing between them. wind less than about 6kts. Light a/c follows to land behind them, spacing unknown. What are the chances of the light a/c being affected by the helicopter vortexes, if any?
Hypothetical situation:-
2 medium twin helicopters landing one after another with about 4 miles spacing between them. wind less than about 6kts. Light a/c follows to land behind them, spacing unknown. What are the chances of the light a/c being affected by the helicopter vortexes, if any?
Joined: Sep 2003
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From: 59°45'36N 10°27'59E
Having done much of my flying from a RNoAF heli base with a certain JHC presence each year , I have some insight into this.
Yes, you will feel wake vortex from a medium helo like a Sea King or Puma, and was taught, and indeed felt that you should stay above the helos approach path if landing closer behind than say 3-4 miles.
From the tower I've seen a Grob get chucked around violently forcing a go-around when spacing up close behind a Sea King. Made him more aware about what "caution wake turbulence" actually means.
Smaller helos like the 412, Lynx etc not that bad, but you do feel their wake more than what their tonnage would imply. You will be affected if you turn in say 1-2 miles behind a 412, but not in such a way that it becomes dangerous IMHO.
Yes, you will feel wake vortex from a medium helo like a Sea King or Puma, and was taught, and indeed felt that you should stay above the helos approach path if landing closer behind than say 3-4 miles.
From the tower I've seen a Grob get chucked around violently forcing a go-around when spacing up close behind a Sea King. Made him more aware about what "caution wake turbulence" actually means.
Smaller helos like the 412, Lynx etc not that bad, but you do feel their wake more than what their tonnage would imply. You will be affected if you turn in say 1-2 miles behind a 412, but not in such a way that it becomes dangerous IMHO.
Joined: May 2001
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From: UK
http://www.aaib.gov.uk/cms_resources...pdf_501305.pdf
Something a bit larger is enough to kill you, sadly.
As I reported elsewhere the prop wash from an aircraft doing engine checks caused me a problem or two recently.
Anything running on the ground needs treating with caution.
Something a bit larger is enough to kill you, sadly.
As I reported elsewhere the prop wash from an aircraft doing engine checks caused me a problem or two recently.
Anything running on the ground needs treating with caution.
Better red than ...
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Aviation Qualifications: CPL
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From: Appleby-in-Westmorland Cumbria England
How about following an Sikorsky 76 type helicopter in a PA28.
Joined: Sep 2001
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From: Toronto
Any SEP needs to treat Heli wakes with great respect
On final in a Citabria, noticed a couple Schweitzer 47s doing hover practice some 50 yards abeam the landing area into the x-wind. Made for an interesting landing
Once landing at the big airport beyond where a 747 was making a 135 degree turnoff to the taxiway and needed a bit of power to make the turnoff The wash was quite noticeable some 100-200' up.
Once landing at the big airport beyond where a 747 was making a 135 degree turnoff to the taxiway and needed a bit of power to make the turnoff The wash was quite noticeable some 100-200' up.
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From: Oxford
Operating out of an RAF base with lots of big helicopters I am often warned 'Caution rotor downwash' but I've always kept well away - same drills as taking off/landing after a heavy e.g. take off before their rotation point and keep above their flight path, same on finals. I expect the Grobs do the same as I've not heard of any upsets.
Tim
Tim
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From: Niort
It is a while since I operated from Aberdeen but ATC were very careful. A couple of incidents of light aircraft being blown over by taxiing heavy twins and some close calls make them much more aware than most ATC.
I recently flew into the wake of an S-92 in a very light aircraft - he was in the cruise doing about 120kts and light - it was a flight test, he went right and cut across my course and I did not climb fast enough. The turbulence was pretty intense although quite localised.
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I would guess as the speed drops off the area of turbulence increases. Either way there is something about the turbulence from choppers than seems to make them pretty difficult for light aircraft. On a calm day 5 minutes plus seeems sensible. If you see an S-92 and are likely to cross its wake climb!
I recently flew into the wake of an S-92 in a very light aircraft - he was in the cruise doing about 120kts and light - it was a flight test, he went right and cut across my course and I did not climb fast enough. The turbulence was pretty intense although quite localised.
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I would guess as the speed drops off the area of turbulence increases. Either way there is something about the turbulence from choppers than seems to make them pretty difficult for light aircraft. On a calm day 5 minutes plus seeems sensible. If you see an S-92 and are likely to cross its wake climb!
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From: Aberdeen, UK
Aberdeen ATC are pretty switched on about it - I departed a few weeks ago through the wake of a landing twin at the end of the runway, and on climb out we had a nice kick in the pants and decent chop even with a good few minutes spacing.
I always give them quite a wide berth if possible, and get off the deck well before where they were (albeit in a C172 so it's not too onerous).
I always give them quite a wide berth if possible, and get off the deck well before where they were (albeit in a C172 so it's not too onerous).
Thread Starter
Joined: Dec 2000
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From: uk
sensing guilt? No way. I fly what I fly. If someone flies something else over which I have no control and end up doing something wrong, it will never be my fault. Why should I feel guilty? i feel bad that someone was involved in an accident at the same airport I fly from.
I asked the question because the aircraft ended up on the right hand side of the rwy, at the threshold. the wind (very light )was just of rwy heading, from the left if I remember correctly on rwy 26. 2 S76's had come in within about 5 minutes of each other. I believe the fixed wing was close behind #2 S76.
?????
I asked the question because the aircraft ended up on the right hand side of the rwy, at the threshold. the wind (very light )was just of rwy heading, from the left if I remember correctly on rwy 26. 2 S76's had come in within about 5 minutes of each other. I believe the fixed wing was close behind #2 S76.
?????
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From: Niort
There used to be some really good video of helicopter wake turbulence on the net - cannot find it this morning IIRC it was done by NASA.
Anyhow the standard stuff about WT still applies and if the wind was very light then it would persist for a 'long' time. With two similar aircraft it is quite likely that the wakes interacted to some extent.
In Aberdeen most people 'know' to avoid the stopping or rotation areas on the runway where choppers have been - even after the usual interval the air is pretty rough - especially on still days.
Anyhow the standard stuff about WT still applies and if the wind was very light then it would persist for a 'long' time. With two similar aircraft it is quite likely that the wakes interacted to some extent.
In Aberdeen most people 'know' to avoid the stopping or rotation areas on the runway where choppers have been - even after the usual interval the air is pretty rough - especially on still days.
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From: Who can say?
I've experienced very significant problems following a Puma into Aldergrove. I was flying a Turbine Islander, separation was about three miles.
I made the silly mistake of not noting where he landed, and I was intending to land long, so flew straight through where his vortex wake was strongest.
Went around, and lived to fly another day.
I made the silly mistake of not noting where he landed, and I was intending to land long, so flew straight through where his vortex wake was strongest.
Went around, and lived to fly another day.
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From: UK
Back in the early '90's, a PPL instructor of mine at the time (an RAF heavy jet man) was killed in a dreadful accident at Oxford, after the PA28 he was instructing in encountered the wake turbulence from a departing S61 whilst on short final - it was British F1 GP day at Silverstone.
As a PPL u/t at the time it hit me hard and always made me very wary of heli-induced turb, especially as the place where I did a lot of my subsequent flying was at Blackbushe (intensive heli-ops, everything up to S92 size these days)....be careful out there!
As a PPL u/t at the time it hit me hard and always made me very wary of heli-induced turb, especially as the place where I did a lot of my subsequent flying was at Blackbushe (intensive heli-ops, everything up to S92 size these days)....be careful out there!
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From: Do I come here often?
Wycombe;
I witnessed that as I was flying in the GP shuttle from there at the time. There was also the C172/Seaking accident at St Mawgan.
I fly rotary for a living and am VERY conscious of the potential for upset that my wake turbulence may cause. A lot of smaller airfields may not realise due to infrequent heli ops. Err on the safe side and give anything above a Twin Squirrel a good wide berth.
Also a lot of smaller airfields don't realise that our downwash can easilly upset a light aircraft when we are taxiing around. Parking us close to a flightline is a recipe for damage, either by the downwash banging control sufaces about or FOD being thrown around.
I witnessed that as I was flying in the GP shuttle from there at the time. There was also the C172/Seaking accident at St Mawgan.
I fly rotary for a living and am VERY conscious of the potential for upset that my wake turbulence may cause. A lot of smaller airfields may not realise due to infrequent heli ops. Err on the safe side and give anything above a Twin Squirrel a good wide berth.
Also a lot of smaller airfields don't realise that our downwash can easilly upset a light aircraft when we are taxiing around. Parking us close to a flightline is a recipe for damage, either by the downwash banging control sufaces about or FOD being thrown around.
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From: Escrick York england
i have also lost count of the smaller aeroplanes and microlights that park too close to the helicopter ,when you point it out to them they take it in had 2 flex wings park 10 foot either side of me once
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From: Do I come here often?
My helicopter mount is a medium sized twin. I was astonished recently when someone parked an R22 within 20' of me and then walked away without tying the thing down. The instructor was most put out when I asked him to tie it down as I was worried about blowing the main blades around.
If I had I suppose it could only have been a blessing to rotary flight
If I had I suppose it could only have been a blessing to rotary flight