Fire Fighting Helo Crash in NZ
An AS350 has crashed killing the pilot while fighting the fires on Christchurch's Port Hills.
Thoughts are with everyone there. One person dead in helicopter crash during Port Hills fires | Stuff.co.nz |
Rest in Peace Brother, another sad day for the Rotory World
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It appears that the registration is shown in the news photograph. ZK-HKW.
Flight aware are reporting that registration also. Pictured here in better days |
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Any facts out yet ??........hit wires ??. sad day, sad day.
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Update on the accident - Port Hills helicopter crash caused by a cable striking the tail rotor
Strangely the local NZ CAA Vector "safety" magazine Jan/Feb issue carried an article about exactly this potential problem in the month prior to the accident. Even worse - nowhere in the article does it say that the pictures in the article depict an incorrectly rigged/operated Bambi bucket!!! Who knew? Vector Magazine Jan/Feb 2017 - Page 7 - External Loads – How Much Do You Really Know? In the case of quite a few operators and the NZ CAA apparently - not enough? From the Bambi Operators Manual - WARNING Using a Bambi bucket with a greater overall length than the distance from the cargo hook to the front tip of the tail rotor on your helicopter could result in a tail rotor strike and possible loss of control of the helicopter which could result in injury or death. Important Note It is recommended that operators, who choose to use the Bambi bucket with a longline, ensure that the longline is at least 50’ long. |
From the report "It was attached to a strop of approximately six metres in length, making a total length for the underslung load of approximately 10 metres."
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Originally Posted by Marv
(Post 9768624)
From the report "It was attached to a strop of approximately six metres in length, making a total length for the underslung load of approximately 10 metres."
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Originally Posted by Marv
(Post 9768624)
From the report "It was attached to a strop of approximately six metres in length, making a total length for the underslung load of approximately 10 metres."
It's not the first time a bucket has ended up in a tail rotor by attaching it with a short strop rather than either direct belly hook or longline hence why the OEM manual requires at least a 50' strop or longer if not belly hooking directly to the hook. |
Some clients require the load, i.e. water bucket in this case, to be attached directly to the cargo (belly) hook or a minimum length of longline must be used, e.g. 25 m.
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Originally Posted by gulliBell
(Post 9768773)
i.e. slightly longer than the distance between the cargo hook and the tail rotor, which that OM warning warns about.
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Originally Posted by Nubian
(Post 9769903)
Slightly!??
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Yep. Nose to tail the AS350 is 10m long. If your displayed understanding is reflecting the common knowledge of the matter in your neck of the woods, it is unfortunately not surprising that this accident occurred... |
I think we all knew what he meant Nubian !! ( and in case of misunderstanding he did say it had to stop 6" short of t/r tip !!). Maybe you have just had a bad day ..
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Originally Posted by nigelh
(Post 9770725)
I think we all knew what he meant Nubian !! ( and in case of misunderstanding he did say it had to stop 6" short of t/r tip !!). Maybe you have just had a bad day ..
Read the previous posts again and see if you understand my point. |
Originally Posted by Nubian
(Post 9770689)
Nose to tail length is irrelevant, cargo-hook to closest point of t/r is not, which is about half the overall length...
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Well you will have to explain that to me then ! If distance from hook to tail rotor is 6 m then doesn't really matter how long the helicopter is nose to tail. If load less than 6 m then doesn't hit tail rotor anything else is capable of hitting so I don't quite see what the total length of the machine has to do with it ????
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Originally Posted by gulliBell
(Post 9771515)
Of course it's relevant. If you've got a load hanging off the hook that is about as long as the helicopter is, if it goes aerodynamic and swings back it's about the right length to put it in the tail rotor. 10m long AS350, 10m long load = danger, it can swing back and hit the tail rotor. Which is what happened in this instance. If you don't understand that I don't know of a simpler way to explain it.
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I think the only time the overall length of helicopter is relevant is when the hook is on the nose !!
Obviously the only important length is hook to t/r tip when pointing at the hook ...... |
Perhaps the important thing is what speed you choose to fly with an empty bucket and how you handle the aircraft in that configuration.
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Crab
You hit the nail there All loads have a Vne, normally most flight manuals have a Vne of 80 kts with something on the hook. Have flown a bambi happily at 70 kts and it has got no where near the tail rotor. The same with it on a 50 ft line. Although I can't quite follow why the line has to be more than 50ft, but if that was the manual says then that is what you do ? The pilot must have been going at some speed to get the bucket into his tail ! |
Would it be more the latter than the former, Crab? The faster you go the more the load will fly up but also the tail will be higher?
But it would be interested to know ... when steaming along at speed, is there an area of circulating rotor wash updraft behind the aircraft and how far back is it at what speeds? |
There seems to be a lot of input from Rotorheads with little or no experience of bucket work. A 50' or 100' line with a Bambi is a necessity for many fire ops when the water source is surrounded by trees or other obstructions, and the ability to fly such underslung loads is part of being checked to the line for fire work. As with most loads it will fly in a predictable fashion, full or empty, and a competent pilot will manoeuvre the machine to put the load where it is needed.
The real issue here would seem to be using a 10 metre (33 foot) line, with resultant flight characteristics which allowed it to put the bucket up into the TR. I'll find some photos later which show the way that an empty Bambi flies at the end of a medium length line. |
Originally Posted by John Eacott
(Post 9772186)
There seems to be a lot of input from Rotorheads with little or no experience of bucket work. A 50' or 100' line with a Bambi is a necessity for many fire ops when the water source is surrounded by trees or other obstructions, and the ability to fly such underslung loads is part of being checked to the line for fire work. As with most loads it will fly in a predictable fashion, full or empty, and a competent pilot will manoeuvre the machine to put the load where it is needed.
The real issue here would seem to be using a 10 metre (33 foot) line, with resultant flight characteristics which allowed it to put the bucket up into the TR. I'll find some photos later which show the way that an empty Bambi flies at the end of a medium length line. |
John
Done quite a lot of lifting and Bambi work, no one has ever really been able to say why a line shorter than 50 ft is so dangerous. Might be being really stupid here but I am sure I don't have a monopoly on stupidity ! |
I am thinking back to basic schoolboy physics. Feel free to shoot me down in flames if I am talking B******ks, but I reckon its like this:
The load is effectively a pendulum. To become a danger to the tail rotor, the amplitude of the swing has to be a large angle (close to 90 deg). To initiate a swing, when you resolve the geometry, involves raising the height/ altitude of the load from its rest position = work/force required. The longer the line, the greater the distance you need to lift the load to get the same angle. So, the greater the force required. So, when you have a shorter line, its more sensitive to sudden acceleration. A longer line will take much more acceleration to achieve the same angle of dangle. |
Originally Posted by Hughes500
(Post 9772401)
why a line shorter than 50 ft is so dangerous.
''Sporty'' handling which a short load facilitates, drop-speed, big change to the buckets weight vs volume (increased drag and decreased weight of the load) and turbulence.... This does not count for bucket work only, but any lightweight loads with a big surface area... Try a lined empty cargo-net as an example... |
Surely the big issue with the length of the strop/rope/line is that if the bucket flies into the TR it is pretty much game over (as demonstrated here) but with a longer line, the bucket has to be higher in order to put the line into the TR and the damage possibly less (though not ensured) from a strop instead of metal fixings on the bucket.
KJ - I don't think that modern helos fly significantly nose down because the horizontal stabiliser keeps the fuselage more level. The difference between 60 kts and 100 kts is unlikely to be that great but the amount of drag affecting the bucket would be much more significant. So you have a perfect storm if you have exactly the wrong length line, fly too fast and then handle the aircraft enthusiastically. |
Originally Posted by gulliBell
(Post 9770383)
Yep. Nose to tail the AS350 is 10m long. So 10m of strop and empty bambi bucket hardware hanging off the hook exposes the tail rotor to impact, which regrettably, brought about the demise here. Had it been 50' of line, the empty bucket would just fly below and aft of the tail rotor zone. Or belly hooked and it's not long enough to reach the tail rotor.
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Originally Posted by havick
(Post 9771790)
You do realize the hook is under the middle of the helicopter and not the nose of the helicopter?
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Originally Posted by gulliBell
(Post 9772687)
I don't get it how you guys don't get it, except @Freewheel who does understand. The cargo hook is usually close to the aircraft CofG, which is a lot closer to the nose than the tail rotor. If the helicopter is 10m long, a 10m empty lifting rig on the hook if it goes aerodynamic is going to put it in range of the tail rotor. If you don't believe me, and heck, I've been slinging loads around the boonies for 20 years, read and comply with any warnings published for your role equipment. Or just look at the photo of what was left of that AS350 on the side of the hill. That's what can happen if you fly a 10m line on a piece of equipment that says don't fly me on a 10m line. Seriously guys, I don't understand what it is you don't understand.
With your explanation could a new pilot think it is ok to fly with a 7 meter long load as it is not as long as the 350.... |
I've had to teach some mentally challenged helicopter pilots in recent years, but I've found there is always a way to explain something to someone who doesn't understand your first explanation, or second. So here goes...
Hang that 10m long line on the nose of your 10m long helicopter. The way it might flail around in flight if it goes aerodynamic it would probably fly pretty close to the tail rotor, but not actually hit it. Now go and hang that same line on the hook of the same helicopter. Bingo, now that rig is potentially flying within range of the tail rotor. I've dinged the underside of the tail boom a few times after loads hanging off 20' or 30' lines have fallen out of nets rigged by qualified load masters, but lucky they were all in B212 or S76 and the tail rotor, being bolted on top of a pylon, was out of range. Had I been in a B206 or AS350 it may well have been a different outcome. As for said new pilot by way of example I would say, refer to the external load section of the operator procedures manual, the RFM, and the role equipment OM, and take heed of what they say. |
Gullibal
The length of the helicopter has got nothing to do with it. the distance between the hook and the tip of the tail rotor is the critical dimension. |
Originally Posted by Hughes500
(Post 9772816)
Gullibal
The length of the helicopter has got nothing to do with it. the distance between the hook and the tip of the tail rotor is the critical dimension. |
Gullibell
In your 10m example your 10 m line will still hit the tail rotor ! Unless I am mistaken the length of a helicopter would be nose to the last point of airframe. Now forgive me but in all the types I fly ( with the exception of those with either a Notar or Fenestron )the tail rotor blades have at least 50% of the turning circle within the total length of the helicopter. It is much more critical to measure the distance between hook and tip path plane of the tail rotor |
I agree !! I may be even thicker than Hughes but I don't understand the relevance of the length of the aircraft either 😳
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Originally Posted by gulliBell
(Post 9772687)
I don't get it how you guys don't get it, except @Freewheel who does understand. The cargo hook is usually close to the aircraft CofG, which is a lot closer to the nose than the tail rotor. If the helicopter is 10m long, a 10m empty lifting rig on the hook if it goes aerodynamic is going to put it in range of the tail rotor. If you don't believe me, and heck, I've been slinging loads around the boonies for 20 years, read and comply with any warnings published for your role equipment. Or just look at the photo of what was left of that AS350 on the side of the hill. That's what can happen if you fly a 10m line on a piece of equipment that says don't fly me on a 10m line. Seriously guys, I don't understand what it is you don't understand.
I think you confused everyone talking about the overall length which isn't really relevant. It's the distance from the cargo hook to the the extremities that that matters as that's where it's swinging from. Once again we are in agreement in not using a short line, and to follow the RFM and the bucket manual. It's just your original post didn't read like that is what you were trying to say. |
Back when we were on a steep learning curve, the BK was tried out with shorter strops than we now know to be ideal. This was either a 20' or 30' from memory, but indicates well how the Bambi flies when empty; quite stable and predictable.
http://www.eacott.com.au/gallery/d/8...h+bucket+1.jpg As a comparison, this is the Bambi directly onto the hook with the correct distance to the TR tips: http://www.eacott.com.au/gallery/d/8111-1/BK117_3_.jpg http://www.eacott.com.au/gallery/d/8...ondilli+01.jpg |
Originally Posted by John Eacott
(Post 9774460)
Back when we were on a steep learning curve, the BK was tried out with shorter strops than we now know to be ideal. This was either a 20' or 30' from memory, but indicates well how the Bambi flies when empty; quite stable and predictable.
http://www.eacott.com.au/gallery/d/8...h+bucket+1.jpg As a comparison, this is the Bambi directly onto the hook with the correct distance to the TR tips: http://www.eacott.com.au/gallery/d/8111-1/BK117_3_.jpg http://www.eacott.com.au/gallery/d/8...ondilli+01.jpg |
Originally Posted by havick
(Post 9774467)
John, what does the Bambi manual say?
If you're implying the photo of VH-BKK was me or my company with a 20-30' strop then you're sadly mistaken. I took that photo while flying in company; my ops we either had the Bambi on the hook or on a 100' kevlar line. My reference to 'we' was that in the 90's we were all on a learning curve and shared experiences, pilots do that. Or used to. |
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