Helicopter crash Hudson River 1

[LittleInch]

Helicopter sight seeing inner York crashed with all dead.

This video looks like it was flying at some speed, then something happens, it seems to change orientation very rapidly which causes the whole tail structure to detach, followed shortly by the main rotor blade and part of the gearbox. Horrible way to go.

https://www.reddit.com/r/CatastrophicFailure/comments/1jwfxh9/full_video_of_the_helicopter_crash_in_hudson

Six people killed after helicopter crashes into Hudson River in New York

Pilot and a family with three children who are believed to have been Spanish tourists were killed onboard aircraft

www.theguardian.com

 

[waross]

There are so many things that could have gone wrong.
Does anyone else remember the days before official safety departments and safety advisors?

Long ago our safety programs were self initiated and self conducted.
It was common for tradesmen to discuss at length any recent accident to workers, and even some notable older incidents.
What went wrong?
Who made a mistake?
What did we not know?
What is the weak point? When it breaks, which way will it fly? DON'T BE THERE!
That was our self taught safety program.

Staying at the same small hotel as helicopter pilots and mechanics I was a fly on the wall for a lot of these sessions.
One possible issue was what the pilots called the stick "Walking the Cabin".
If the pilot was startled and made an abrupt cyclic control movement, the rotors may subject to gyroscopic precession.
An abrupt backward movement of the cyclic stick may cause rotor and the stick to abruptly jump 90 degrees to one side.
That action will in turn cause an abrupt movement forward.
That action will in turn cause an abrupt movement to the other side
That action will in turn cause an abrupt movement backwards.
Rinse and repeat.
I listened to a pilot describe his own experience when the stick "Walked the Cabin".
Fortunately the action damped out before the helicopter came apart.
Another story was about a Vietnam era (MASH) helicopter setting up a new exploration camp.
All of the equipment was packed in large duffel bags.
A couple of bags would be set on each side racks. The helicopter would touch down at the remote camp and the ground men would pull the bags off and the pilot would immediately take off for another trip.
One one trip, a bag was not pulled clear but was left partly on one skid. The pilot thought he was clear and took off.
When the end of the bag dropped of of the skid it upset the equilibrium of the helicopter enough that the helicopter crashed. (From within a foot or so of the ground.)
One mechanic delighted in pouring over accident reports and sharing with us the most dramatic or outrageous accidents.
This was at a time when the Vietnam war was recently over and these pilots were ex US service pilots who had many hours flying time in combat and at times under fire.
There are just so many things that can catastrophically upset the equilibrium of a helicopter.
A possibility is a near catastrophic event, followed by pilot error that leads to an unrecoverable catastrophic error.
Waiting for the report.

 

[Tomfh]

ets. This kind of speculation is healthy

Agree. What else are we here for? Sharing knitting tips?

 

[LittleInch]

I'm with xr250 and have been for a while.

I'm not actually sure if anyone is going to be able to determine cause from effect from such rapid and violent set of events.

Unless they've got better footage from somewhere or can take the gearbox apart slowly to see what might have happened, I think it will be an educated guess, basically not much more than we have as there is no FDR or CVR. Maybe the maintenence records will show some previous fault, but it does look like the operator was a bit of a fly by the seat of his pants low rent type.

 

[mfgenggear]

I never seen such damage in mid flight.
Usually it's lost of tail rotor or gear box seize.
But mast with gear box separate.
Boon break up. Something went terribly wrong.
I saw that video. I was in disbelief.

 

[Sym P. le]

Sorry waross, I can't put my head in a bag.

 

[Alistair_Heaton]

My thoughts are what has enough energy either kinetic or potential in a rotor drive train that when stopped or released can throw that big a mass away while snapping it's mounts?

 

[Garbage1]

Reflecting on childhood lessons learned, the hard way. Do you remember the large metal cases drills, for drilling holes in steel? The ones without case isolation from electricsl shorts.

Those drills did not have clutches to prevent torque transfer to user, when the drill bit bound up.

And those drill bits did not have near the rotary kinetic energy of helo blades?

Yet, that drill would break bones/connective tissure and throw the operator away.

Theories are just fact and science based speculation, until they are validated or eliminated.

Carry on with the engineering analysis, as we all know that management/politics/hidden agendas can cover up the best engineering determinations.

 

[Alistair_Heaton]

That's exactly my thoughts

The disk has enough energy to land it with an engine failure and autorotate.

I suspect they already know the primary cause. They are in the guts of the why the primary cause existed. I very much doubt it will be an original design issue.

 

[TugboatEng]

I think the most notable detail is that the top deck of the helicopter separated from the frame with the rotor and transmission attached. How is the deck secured to the helicopter frame?

 

[mfgenggear]

 

[Garbage1]

Recommend watching above video with mute function engaged and a stiff drink in hand.

 

[mfgenggear]

not the bell 206 but how it works

 

[Tomfh]

I think the most notable detail is that the top deck of the helicopter separated from the frame with the rotor and transmission attached. How is the deck secured to the helicopter frame?

It’s wild that the whole thing tore off. Maybe it had a defect already. Seems wierd that all the relative flimsy parts stayed intact.

 

[tdmidget]

Recommend watching above video with mute function engaged and a stiff drink in hand.

A stiff drink every time I hear "rotational torque".

 

[GregLocock]

As this makes clear, the skid unit (tractor terminolgy) holding the turbine/gearbox/rotor system is the strength member, the cabin is just an alloy tube for holding passengers.

 

[Sym P. le]

I think there's a little more to it than that. rotational torque

 

[TugboatEng]

Engineering papers typically have an abstract so that readers can quickly identify relevance to their inquiry. Can we please require that posted videos have some type of abstract so we don't have to wait 22 minutes to find that nothing interesting has been discussed?

 

[TugboatEng]

Greg, it appears there is very little structure to withstand w moment about 11 and 12. The mast does appear bent in the photos. If it bent while the rotor was perpendicular to that skid unit that could create quite the moment.

However, the structure that we see still attached to the transmission does not appear deformed. We have no high resolution photos at this time.

 

[XR250]

My thoughts are what has enough energy either kinetic or potential in a rotor drive train that when stopped or released can throw that big a mass away while snapping it's mounts?

The rotor?

 

[Alistair_Heaton]

It may be. There are a few things with enough energy and solid connection to other bits.