Helicopter Rotor Strikes Officer

hopmedic

hopmedic

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Rich
hopmedic said:
http://www.foxnews.com/us/2012/07/1...ed-by-helicopter-rotor-blade/?test=latestnews

Fortunately, the guy with a broken leg that they were rescuing was a doctor, so he and the other hikers saved the officer's life. That's good.

Now, of course knowing that I don't know the whole situation, I have to wonder about the wisdom of flying a helicopter that just had a blade strike?
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Or what...shut down on that piece of granite and wait for Mx to fly out there with a mechanic and a spare blade...set down on the cliff and fix it?
 
In an 'in motion' strike, it's gonna let you know if it's gonna come apart. There really isn't a lot that's going to happen hitting a human that's going to set up a 'downline' hidden failure. When a helicopter rotor hits something, either the rotor will come apart in very short order or it'll get you home, the shake will let you know which.
 
Captain said:
Or what...shut down on that piece of granite and wait for Mx to fly out there with a mechanic and a spare blade...set down on the cliff and fix it?
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While the injured officer bleeds to death?
 
Exactly. An incident like that while perched on the edge of a slab of granite in a hostile environment is an inflight issue. It's like continuing after an engine failure in a multi. You keep going until you get the aircraft and people to a place that's safe to shut down.
 
Captain said:
Exactly. An incident like that while perched on the edge of a slab of granite in a hostile environment is an inflight issue. It's like continuing after an engine failure in a multi. You keep going until you get the aircraft and people to a place that's safe to shut down.
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Except that it wasn't a multi.
 
That story is movie material. You have a helicopter perched precariously on the side of a cliff by an obviously skilled and heroic pilot. Add to it an obviously heroic emergency rescue person who then gets clobbered most likely in the head by a rotor blade and lives (thus far)! Who then gets rescued himself by a heroic battlefield (war hero) trauma surgeon who is suffering from his own severe injuries.

Man, you can't make that stuff up.
 
While it was most likely unavoidable, for the moment the outcome is positive with all people surviving, even though the one guy is has critical injury. Thankfully it wasn't a different outcome.
 
hopmedic said:
For crying out loud, people - it was a question!
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No worries, and it was answered in a manner of operational considerations. You are correct to question the wisdom of continued operation and I guarantee it was way up there in the PIC's mind as well. As with any command decision of this type you have to take in the data you have and figure out your best course of action.

The primary consideration is going to be vibration, if it's shaking hard it's a shutdown before it all comes apart, that's the first 3 seconds after the strike. If it hasn't come apart in the first three seconds, you've got time. Now you have to assess the situation; you have an injured hiker and a crew member, likely a buddy you have nearly killed, lying on a rock that if you shut down you'll likely be blocking the only rescue zone.

Your options are basically set it down at the edge, get everybody out, stand on the skid and give it hard cyclic to dump it over the side and clear the LZ. Now you have to wait with bare minimal medical gear, you, and 2 patients and whomever to be picked up be whatever other resource is available. That or get everyone loaded ASAP and get the thing to the hospital landing pad, or as far as you can before it starts vibrating too much to continue.

That is the reality of being PIC, you not only have to question the wisdom of your thoughts and actions, you have to decide on them within seconds often, sometimes less. Sometime you decide right, sometimes you decide wrong, when you decide wrong, people die. That is what it means to be 'in command' it's all on you, nobody else to blame, nobody else to ask.
 
Captain said:
Nobodys dumping on you. It was a question and folks tried to answer it.
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Exactly, we were tying to present you with the questions and considerations that the PIC was facing at that moment. That's what it's like, everything suddenly went to hell and now you have 2 emergencies and an unknown structural/mechanical condition. As PIC you don't have a lot of time to work it out. If you feel persecuted as we toss these questions in a comfy internet forum, how do you think he felt at at that point? This is as much part of learning to be PIC as is preflighting and fuel planning.
 
Ok - I overreacted, having just arrived home from a longer-than-normal commute (that I hate anyway). Thanks for the explanations. I didn't realize that the helicopter would tell you that quick if it's going to fall apart or not. As for the medical emergency, that one I can handle - 10 years as a medic. As for it being a buddy, been there, too. Did CPR on my cousin 45 minutes after he was hit by a train, and amazingly had almost no externally detectable injuries (aside from the lack of a pulse). Didn't let anyone in the ER know he was my cousin until after he was pronounced dead, AND I'd cleaned up the trauma room around him. Then I lost it big time. But I know that most people could not have done that.
 
In all but the smallest of helicopters, the human body is not capable of causing severe damage to a spinning main rotor blade.
 
darrell said:
In all but the smallest of helicopters, the human body is not capable of causing severe damage to a spinning main rotor blade.
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Wow. How about the engine? No damage to worry about? Like whatever would be the cause of the rule to tear down an engine after a prop-strike?
 
There will be a sudden stoppage inspection, but I have seen quite a few rotor strikes and the only time we had to replace the gearboxes was when we tried to use a tail rotor as a ditch witch. For the main rotor, the largest tree branch we've hit was 3 inches and all it did was dent the tip caps. (on an Mi-17, which is not really a fair comparison, I'll admit)

EDIT: regarding the engine, if it was a turbine, the engine is not directly connected to the gearbox, so no worries there.
 
darrell said:
There will be a sudden stoppage inspection, but I have seen quite a few rotor strikes and the only time we had to replace the gearboxes was when we tried to use a tail rotor as a ditch witch. For the main rotor, the largest tree branch we've hit was 3 inches and all it did was dent the tip caps. (on an Mi-17, which is not really a fair comparison, I'll admit)

EDIT: regarding the engine, if it was a turbine, the engine is not directly connected to the gearbox, so no worries there.
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Really? Interesting.
 
hopmedic said:
Wow. How about the engine? No damage to worry about? Like whatever would be the cause of the rule to tear down an engine after a prop-strike?
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Think of the difference in inertia between a rotor blade and a prop, rotor much higher mass and much slower speed than a prop. Next you have to consider the inertia of the item struck. Most likely our rescuer was wearing a helmet and climbed into to bottom side of a blade. Now this is extremely lucky as the back side is the 'push away' side.

I was working on a 210 with another mechanic and we were setting the fuel servo. I was in the plane running it and he was next to the engine on the left. I had just dropped the engine to idle and my partner needed to go grab a tool and turned to stand up. As soon as he turned his head (before he started to stand up) I knew what was going to happen (where the eyes go the head goes, where the head goes the body follows) and I pulled the mixture but not quite fast enough and he stood head first (luckily) into the back of the prop which bounced him back into the door with a small mark on his forehead.

With a helicopter rotor and climbing into it, I imagine that the trooper ended up with a broken neck out of it, hopefully with no permanent damage.
 
Henning said:
Think of the difference in inertia between a rotor blade and a prop, rotor much higher mass and much slower speed than a prop. Next you have to consider the inertia of the item struck. Most likely our rescuer was wearing a helmet and climbed into to bottom side of a blade. Now this is extremely lucky as the back side is the 'push away' side.

I was working on a 210 with another mechanic and we were setting the fuel servo. I was in the plane running it and he was next to the engine on the left. I had just dropped the engine to idle and my partner needed to go grab a tool and turned to stand up. As soon as he turned his head (before he started to stand up) I knew what was going to happen (where the eyes go the head goes, where the head goes the body follows) and I pulled the mixture but not quite fast enough and he stood head first (luckily) into the back of the prop which bounced him back into the door with a small mark on his forehead.

With a helicopter rotor and climbing into it, I imagine that the trooper ended up with a broken neck out of it, hopefully with no permanent damage.
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Ok. I didn't know what you meant when you said, "Push away side" until I got down to the part about the airplane. Ouch. Wow. Praise God this officer is still alive.
 
Maybe next time god could try just a bit harder and keep him from getting hit by a helicopter rotor blade in the first place.
 
Let me stick my nose into this as a guy who has a few hours in helicopters and has made a few ground extractions in high angle scenarios. A few things to consider:

1.)The human body is mostly water, rotors are not.

I do not know the specific data for the rotor involved, and am making the assumption that the pilot was holding attitude on the ground with power from the description in the story. In such a case the inertia of the spinning rotor would slice and dice with very little deformation of the rotor. You are actually more likely to get a serious ding on a rotor that is slowing down because the forces are not helping stiffen the blade.

2.) Helicopters are finicky little ******* who will let you know if they are grumpy. If one rotor had lost as much as a fraction of an inch of material the cyclic would be dancing like a drop of water in a frying pan. I have trimmed spruce trees and flown away smiling. (Of course an inspection followed the landing.)

3.) The officer who was struck was either careless, or had to make a calculated guess that he could clear the disk given the terrain and his route. This is part of the game in high angle terrain. Seeing a rotor disk running at speed in daylight is not easy. It is actually easier to see the blades at night because a light shined up at the disk shows the path very clearly. At night in rain is even better because of the sheen the splattering raindrops make.

Without seeing the landing site and the route the officer took it is impossile to figure out exactly what happened. Had he been operating under a HH3F I doubt the impact would have been felt in the cockpit.
 
According to one story, the engine had been shut off and the rotor was spinning down. FWIW, CHP flies AS350s.
 
I'm reading "Chickenhawk", by Robert Mason. He mentions that his Huey blades routinely chopped through tree branches when he flew in Vietnam.
 
Rigged4Flight said:
I'm reading "Chickenhawk", by Robert Mason. He mentions that his Huey blades routinely chopped through tree branches when he flew in Vietnam.
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I never would have expected most of these situations you've all told me of, but this one... Wow!
 
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