Multiple camera heli crash

Robinson R44, at least the rotor didn't depart the aircraft while flying.

Lucky folks. Glad they only had minor injuries and will recover.
 
Any idea what caused it to crash? Seemed under power when it went in.
 
Landing sideways doesn't seem logical. "Lest the earth rise up and smite thee" just jumped into my head... Glad the injuries were "minor."
 
az350x said:
Landing sideways doesn't seem logical. "Lest the earth rise up and smite thee" just jumped into my head... Glad the injuries were "minor."
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Unless there was an issue with the anti-torque rotor or linkages and the pilot had all the pedal he could use put in and could not straighten out.
 
As he came over those trees I didn't see any indication of wind at all. Looks like he just tried to set down while moving sideways to me.
 
A gust of wind is hard call for this one. Not much time to react at 150 agl.
 
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New Mexico, summer time, I'd be leaning more towards a density altitude type problem that lead to settling with power. Sounds too that the loading was probably a bit high too for the conditions
 
Forward speed looked high enough to rule out settling with power. My guess, the pilot answered his phone at the wrong time...
 
ClimbnSink said:
Forward speed looked high enough to rule out settling with power. My guess, the pilot answered his phone at the wrong time...
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Well what ever the cause there's no excuse for touching down with sideways motion. He should have checked that and could have saved a lot of grief.
 
Art VanDelay said:
Well what ever the cause there's no excuse for touching down with sideways motion. He should have checked that and could have saved a lot of grief.
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Well if he truly had SWP that could explain the right yaw on touchdown. He probably had full collective and full left pedal in. Only thing he could do was ride it down in that case. Sounds like they had a full load of people and equipment also.
 
How much main rotor thrust is lost when full left pedal is in? I'm assuming it takes a larger portion of the total energy available to run the tail rotor full out...
 
3393RP said:
How much main rotor thrust is lost when full left pedal is in? I'm assuming it takes a larger portion of the total energy available to run the tail rotor full out...
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Edit: I see you said "full left pedal". Well that could be significant based on aircraft and configuration. Applying full left pedal in an aircraft at a hover and is lightly loaded probably won't be a problem for the engine or trans. Although you might exceed the yaw rate limit if that particular aircraft has one (UH-60 30 degrees per second). Applying full left pedal with an aircraft already at max TRQ will create an over TRQ and most likely corresponding rotor droop. Normal application of left pedal generally produces a small TRQ (1-2 percent) increase which in turbine aircraft is almost unnoticeable on the controls.

My comment above is the inherent problem with SWP, which would appear to be in this case. In SWP the knee jerk reaction is to apply collective to arrest the descent. This creates TRQ which the engine can't overcome, therefore a droop in rotor rpm. So, you have a situation with a lot of TRQ that the tail rotor is trying to counter with a decreased amount of thrust due to the rotor droop. End result is generally a right yaw in impact. Probably not as much as loss of tail rotor thrust or loss of tail rotor effectiveness but a yaw none the less.

There's another vid on YouTube that shows an R44 doing a quick stop maneuver that resulted in SWP. His low rotor light / audio is going off and it too had a right yaw prior to impact. In the above vid it almost sounds like at 19 secs you can hear it in the background??? I don't know, it might be just me. Still, my guess is SWP. Based on the probable high DA, heavy load and rapid change in wind, it would be a good scenario for it.
 
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He flies right over a power pole before impact.

He may have clipped the top wire?
 
pbramlett said:
this one? http://youtu.be/1B3aUWSG0KE
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Yep, that's it. You can see he had a little bit of right yaw going on as well. Engine is running but you can see the low rotor light (far right) and audio going off. Just simply asking too much from the engine. If he done this quick stop slower he might have pulled it off. Could've been a tailwind in this case as well. Who knows.
 
Skylane81E said:
That has to be a sickening feeling being full power, yet still descending, with insufficient altitude to do squat about it
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It is a sickening feeling pulling in an armfull of collective and the low rotor goes off and you start to settle. Been there before. :(

Luckily in both the above vids it occurred at a low enough altitude that no one was seriously injured. I used to teach a class on aircrew coordination training (Army CRM) and part of it was a presentation on high altitude ops. Even with detailed performance planning we still find ways to breakdown aircrew coordination and wreck aircraft into the sides of mountains. Sometimes all it takes is a gust of wind from the right direction. Sometimes an unexpected higher than planned DA or weight. Sometimes (Mt Massive accident) the crew just simply didn't realize they were operating outside the envelope of the aircraft.
Critical you know and understand the data when you're max performing it in mountain ops.
 
Mcfly, thanks for your informative answer to my question.

:yes:
 
3393RP said:
Mcfly, thanks for your informative answer to my question.

:yes:
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Anytime. I was just reading on copters.com that it takes 5-30 percent of engine power to drive the tail rotor. That sort of data isn't published in any of my flight manuals so not sure how acurrate it is. They also say a lot of factors are in play with that such as type aircraft and weight.

I can tell you from a practical point of view I always try and give myself a right turn bailout if I'm in danger of drooping the rotor. I drooped the rotor once in Afghanistan with a Black Hawk doing resupplies at 7,700 ft, 88 degrees and 35 kts of wind. All I had to do was lower the collective slightly, lower the nose, right pedal and bail to right. It's not always possible to have a bailout that works though. I think wYe had 3 UH-60s and 2 OH-58s have SWP accidents during my year there. All situations where they just didn't have the altitude to recover.
 
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What's 'SWP' and 'drooping' the rotor?

Does it have something to do with the RPM of the engine not being high enough to deliver peak power and the pitch of the rotors being too high causing excessive drag?
 
Captain said:
What's 'SWP' and 'drooping' the rotor?

Does it have something to do with the RPM of the engine not being high enough to deliver peak power and the pitch of the rotors being too high causing excessive drag?
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SWP= settling with power
Drooping the rotor is when the rotor goes below a referenced value. Hopefully that's 100 percent but the alarms will go off usually around 95 percent Nr.

What you describe is generally what SWP is. In my example above the book said I had 97 percent TRQ available based on those particular engines (engine TRQ factor) and DA. Based on our predictions we needed around 93 percent TRQ OGE to pull off the resupply. Well all it took was me applying left pedal (requires more pwr) with a right crosswind (bad) to droop the rotor and send off the low rotor alarms. I looked down and noticed I was now pulling over 100 % TRQ. Since this is over what the engines can produce (TGT limiting) you're gonna start to come down. Only thing you can do is ride it down or in my case right forward cyclic, reduce collective and get above an airspeed (ETL) to fly away. Pretty scary stuff when it happens with grunts looking up at ya on a mountain top and you have to bailout to the right so you don't land on them.

There's another specific aerodynamic condition that falls under SWP and that called vortex ring state or VRS. That's not necessarily a hot and heavy situation either. Basically it's a condition where the helicopter is descending at such at rate that it's settling in its own down wash and the upward flow of air is creating a second vortice on the middle of the blade. Very scary as well because increased collective sometimes aggravates the condition, increasing the descent rate even further. Generally the flight mode conducive to this is a slow (10 kts) steep approach, with moderate ROD (300 + FPM) and having power applied (20-100 percent). It's probably the most dangerous condition for us in EMS because we're almost always doing high vertical landings.

If you do a search of SWP and VRS you see forums with heated discussions on the topics. Some believe they're two separate conditions while others believe they're one in the same. It's not a discussion I'll get into on POA though. :)
 
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RotorAndWing said:
Awww, c'mon. :rolleyes:

:rofl::rofl::rofl:
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All I'll say is my FAA Helicopter Flying Handbook and my Army Fundamentals of Flight book both use the terms interchangeably.
 
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