Why is this?

[jim63]

I have seen pics of a helicopter towing a barge and others of helicopters lifting and moving just about anything you could possibly think of.Why or what causes this one to crash trying to tow a boat?
CkH6uPBPymY

[HeliComparator]

Its a variant of "dynamic rollover" - with the heli attached to a draggy object near the bottom of the heli, and with the top (rotors) of the heli pulling forward, there is a couple (ie twisting force) that causes the heli to pitch down. The pitch down increases the pulling force from the heli, which increases the dragging force from the boat and it all gets rapidly out of hand. It doesn't take much for this couple to exceed the control power of the heli at which point its unrecoverable.

HC

[charlieDontSurf]

They explained this crash on a TV show, and said that the rope snapped.

That's why it suddenly looses control. The weight from the boat dissappeared when the helicopter was at a critical attitude and with quite high power-setting. That's also why it yaws.
That's what they said in the TV-show anyway..:8

[chopper.al]

If you look at the rope it's attached at the door on the left hand side of the helicopter. When he starts to tow the boat forward this would cause the helicopter to twist to one side and ultimately crash. (The Centre of Gravity is being moved towards where the rope is attached and may actually put the new CoG out of limits)
The helicopters you see lifting or towing stuff would probably be attached to a harness on the underside of the helicopter at or close to the CoG, this would make lifting and towing possible. The lifting point is pretty much directly below the main rotor shaft and any weight added anywhere other than this lifting point will change the CoG.

[MightyGem]

I have seen pics of a helicopter towing a barge
Something like this?
CH53 mine clearing:
http://www.electrical-res.com/EX/10-18-01/CH-53E_8.jpg

[widgeon]

or this

http://www.internetage.com/rotorcraft/unusualimgs/towing_1.jpg (http://www.internetage.com/rotorcraft/unusualimgs/towing_1.jpg)

[Heli-Ice]

Why or what causes this one to crash trying to tow a boat?


My trusty memory tells me that in an ancient post on Pprune, someone explained that the helicopter went into the water because of CG out of limits, over torque and loss of tail rotor effectiveness.

[Agaricus bisporus]

If the silly bugger had taken it easy and not tried to drag the boat off in a collective-to-the-armpit max effort acceleration he would perhaps have got away with it.

I'm not really happy with he C of G explanation, surely C of G is a property related to the loading of the aircraft itself, though I can see where this argument is coming from - I think a far clearer explanation is the dynamic couple between the aircraft's c of g and the force from the load overtaking the control authority of the aircraft as described in the first reply by HeliComparator, no doubt made worse by being laterally offset so much too. Just a brainless thing to do.

The CH53 hauling a mine-sweeping sled and the Little Wokka dragging a hover-barge are the result of a great deal of thought and calculation of the moments and forces involved and subject to strict limitations in all sorts of ways. Something the showboating dimwit in the Jetranger clearly did not consider.

Why? Who was drowning? What was the urgency? What was the point?

I wonder if his girlfriend was impressed??? Cos that's what it looks like to me; an uber macho f&ckwit with too much tosstosserone showing off to his bird on the beach.

[BlenderPilot]

Ok I guess I can tell you now . . . .

The accident happened in Valle de Bravo Mexico, it took place during the filiming of a TV show, the actor was told a million times to position the rope so that it would drop under the belly of the helicopter and that under any circumstances not over the skid.

So he did just that the first few times, it had been rehearsed and done like 5 times before without a problem, but on the last take the actor left the rope over the skid with the resulting dynamic rollover.

Tha pilot was VERY experienced, he had flown with Swarzenegger, Stallone, H. Ford, VanDamme, DiCaprio, on the filming of many different movies that have been filmed here.

You can see some eye opening footage of the work this pilot had done here . . .

YouTube - Filmación Aerea (http://www.youtube.com/watch?v=aBfTpqiPH5I)

[Benjamin James]

What's worse, the actor stuffing up, or the audience laughing like it's just another video of someone being hit in the nuts :ugh:

[BlenderPilot]

It is pretty sad, it was just an accident.

[Torquetalk]

It's only canned laughter, think most real people would react differenly once over the age of 14 (developmentally speaking).

I've always seen that video and just assumed the pilot was being a dick. Thanks for clearing that up Blender. There's often more to most situations than meets the eye. It reminds me of a CRM course I went to a while back where the trainer showed Dennis Kenyon's accident in a similar light: the consequences of flying foolishly. That he had no idea of who Dennis Kenyon is and the circumstances was plain pitiful. But hey, ignorance is bliss.

TT