Helicopter crashes in only open space

[Crouching Leopard]

Ok that's sounds right.

I think I'd rather be on the bigger wings of a fixed aircraft than those skinny little guys on the helicopter having to support all that weight as long as it is spinning. On a hot day in the mountains, the density altitude will actually prevent a helicopter from taking off. It makes all kinds of noise but never leaves the ground. An airplane has to lean out the mixture on the piston engines and it takes up more runway to get off the ground, but it also gets leaned out when it flies up to a higher altitude.

But now our quads fly on 4 of them, but if even one of them has a problem, we're going to go in the direction of the slowest turning props. Quite nice to see 4 props turning at once!

I have a friend who flies a Robinson. Keeps asking me to go up with him. I've convinced him I am a coward and its not my thing. He is right!

 

[Deleted member 93449]

Very sad situation and had to be terrifying for the pilot and passenger. Condolences to the families.

For those that know these helicopters, is there anything a pilot could have done to induce a tail rotor failure and separation? Or would that type of failure always be the product of metal fatigue, stressed caused by some out of balance condition in a mechanical system?

 

[Cymruflyer]

Very sad situation and had to be terrifying for the pilot and passenger. Condolences to the families.

For those that know these helicopters, is there anything a pilot could have done to induce a tail rotor failure and separation? Or would that type of failure always be the product of metal fatigue, stressed caused by some out of balance condition in a mechanical system?

It's not common for a tail boom failure from fatigue. This was a lesson/training flight I'm assuming, since there was a student and instructor on board, from what I gather. A tail boom strike results from the PIC nosing the helicopter over forwards too hard, which causes the aircraft to tilt over forward, raising the tail boom up and into the plane of the rear part of the rotor blades. Imagine those blades being like a disk, and the tail boom comes up and makes contact with that disk of spinning rotor blades.

This can also happen with PIO, whereby the pilot makes corrections but too much and then counters that with an opposite correction and each time it is too much and too late to get yourself back into a safe and level flight attitude. If this goes on for a few seconds, maybe not even that long, depending on how severe the over corrections are each time, it is possible to get things, (aircraft frame and rotor blades) moving in opposite directions and again causing the rotor blades to impact a part of the helicopter frame.

The same thing happens with fixed wing aircraft, PIO that is, but the results can be less severe, when compared to a rotorcraft. Students often make these mistakes, and the key is to quickly recognize what is happening and taking immediate action to dampen those moves to get things back on an even keel. Early on in flight training the instructor would immediately take back control and fix the PIO. However, as a student pilot builds time, there comes a fine line whereby the instructor must allow certain mistakes to take place and guide the student back to stable flight attitude.

It is important to catch this quickly and talk the student through what to do, despite this having been previously discussed and practiced. By allowing the student to make the corrections to their own inadvertent actions, you teach them to understand how they got into that situation and what they need to do to get themselves out of it, for their future safety. It's like teaching a baby to walk, early on you try and catch every stumble but as things progress, you need to hold back a little and let the toddler go so they can catch their own balance and fix their mistake themselves. That is the hard part, to watch as something is unfolding but holding back to let the subject sort it out themselves.

Of course, we have no idea what took place in this tragic accident, so there is no point in speculating who did what or did not do what. If it was structural, you would have hoped/expected the maintenance crew to have spotted and rectified the problem before it reached a catastrophic failure level. If it was pilot induced, you would expect the instructor to have hopefully jumped in in time to correct an emerging and potentially deadly problem. Then again, maybe the instructor had a heart attack, or the student was suicidal, we just don't know and therefore, it's pointless to speculate. Hope this helps you understand.

Students do very stupid things sometimes, right out of the blue, you just have to be ready for everything, when giving flight training. The longer you have been doing it, the more things you will have seen happen and the better prepared you will be. I used to think of every new student that turned up, as someone who had come here that day, to kill me, and it was my job to not let that happen.

 

[Deleted member 93449]

It's not common for a tail boom failure from fatigue. This was a lesson/training flight I'm assuming, since there was a student and instructor on board, from what I gather. A tail boom strike results from the PIC nosing the helicopter over forwards too hard, which causes the aircraft to tilt over forward, raising the tail boom up and into the plane of the rear part of the rotor blades. Imagine those blades being like a disk, and the tail boom comes up and makes contact with that disk of spinning rotor blades.

This can also happen with PIO, whereby the pilot makes corrections but too much and then counters that with an opposite correction and each time it is too much and too late to get yourself back into a safe and level flight attitude. If this goes on for a few seconds, maybe not even that long, depending on how severe the over corrections are each time, it is possible to get things, (aircraft frame and rotor blades) moving in opposite directions and again causing the rotor blades to impact a part of the helicopter frame.

The same thing happens with fixed wing aircraft, PIO that is, but the results can be less severe, when compared to a rotorcraft. Students often make these mistakes, and the key is to quickly recognize what is happening and taking immediate action to dampen those moves to get things back on an even keel. Early on in flight training the instructor would immediately take back control and fix the PIO. However, as a student pilot builds time, there comes a fine line whereby the instructor must allow certain mistakes to take place and guide the student back to stable flight attitude.

It is important to catch this quickly and talk the student through what to do, despite this having been previously discussed and practiced. By allowing the student to make the corrections to their own inadvertent actions, you teach them to understand how they got into that situation and what they need to do to get themselves out of it, for their future safety. It's like teaching a baby to walk, early on you try and catch every stumble but as things progress, you need to hold back a little and let the toddler go so they can catch their own balance and fix their mistake themselves. That is the hard part, to watch as something is unfolding but holding back to let the subject sort it out themselves.

Of course, we have no idea what took place in this tragic accident, so there is no point in speculating who did what or did not do what. If it was structural, you would have hoped/expected the maintenance crew to have spotted and rectified the problem before it reached a catastrophic failure level. If it was pilot induced, you would expect the instructor to have hopefully jumped in in time to correct an emerging and potentially deadly problem. Then again, maybe the instructor had a heart attack, or the student was suicidal, we just don't know and therefore, it's pointless to speculate. Hope this helps you understand.

Students do very stupid things sometimes, right out of the blue, you just have to be ready for everything, when giving flight training. The longer you have been doing it, the more things you will have seen happen and the better prepared you will be. I used to think of every new student that turned up, as someone who had come here that day, to kill me, and it was my job to not let that happen.

Thanks for the thorough explanation. Does PIO stand for pilot induced oscillation?

 

[Cymruflyer]

Thanks for the thorough explanation. Does PIO stand for pilot induced oscillation?

yes

 

[lookout]

Watched video again. Something else I noticed.

Helicopter is flying somewhat what we call death spiral, but the main rotor is still going and it does look like 4 blades, but it chops up the remaining part of the tail section, and then it loses all flight characteristics.

 

[lookout]

A guy from a year ago posting about whether these are safe or not.

 

[Cymruflyer]

Watched video again. Something else I noticed.

Helicopter is flying somewhat what we call death spiral, but the main rotor is still going and it does look like 4 blades, but it chops up the remaining part of the tail section, and then it loses all flight characteristics.

The tail boom got chopped so immediately they lost the counter rotation affect of that tail rotor to the torque of the engine. That torque will immediately cause the body of the helicopter to begin to rotate. It would require an instantaneous stopping of the engine to stop the torque effect on the body, which just is not possible. The main rotor would be adjusted by the PIC to go into autorotation in such an event, as it descended. Sort of the effect that you see when those little helicopter seed pods fall from a tree in the autumn, as they spin and slow the descent of that seed pod.

When close to the ground the collective pitch stick would be pulled to increase the angle of attack on the main rotor blades which would arrest the descent speed, however, at the same time this added drag on the blades of more pitch, would also slow the rotor blades. That is why this exercise is critical to saving life, so has to be done at the right height and right amount to reduce descent rate to be survivable, but the helicopter has to have forward speed as well to help in all this.

The blades would work in the same way that the blades on an aurogyro copter would work to give it some lift as it moved down and forward through the sky. Since autogyros have no power going to the main rotor blade when flying, it is just blade angle plus angle of that sort of disk of the rotor blades to keep positive load on the blade disk and forward speed, provided by a pusher engine in a gyrocopter, that keeps it flying. If the collective is pulled too early, the rate of descent slows too early/high and the blades will slow down to the point of having no further lifting effect and then the copter just drops the rest of the way to the ground. Pulled too late and you don't arrest the descent speed in time and you impact the ground hard or very hard. So it is a very skilled thing to have to do, to get it right.

When you lose a tail rotor and part of that boom, things are very different and often or mostly, not survivable. As the body was spinning the blades were having less of an effect for autorotation plus things were getting very unstable and that is why it began to turn over and when the blades lost the positive loading, they would be bent from the airflow as it dropped and as you saw, would again impact the tail boom. Interesting that they seemed more or less intact, despite the tail boom having come apart. again not wanting to speculate but maybe the boom failed without an initial rotor impact, at the start of it all.

You might look up the specs on the R44, but I believe they only have two blades on the main rotor. What you might be seeing is the optical illusion from a camera shutter, making it look like it has four blades, just like a spinning wheel in the right lighting can often look like it is suddenly spinning backwards. I'm no expert on helicopters, so maybe a real helicopter pilot can jump in and give us some insight here. Again, it's best not to speculate on what happened, leave that to the expert investigators. I would like to know though, what was the initial cause of this failure and subsequence tragic accident.

 

[lookout]

The tail boom got chopped so immediately they lost the counter rotation affect of that tail rotor to the torque of the engine. That torque will immediately cause the body of the helicopter to begin to rotate. It would require an instantaneous stopping of the engine to stop the torque effect on the body, which just is not possible. The main rotor would be adjusted by the PIC to go into autorotation in such an event, as it descended. Sort of the effect that you see when those little helicopter seed pods fall from a tree in the autumn, as they spin and slow the descent of that seed pod.

When close to the ground the collective pitch stick would be pulled to increase the angle of attack on the main rotor blades which would arrest the descent speed, however, at the same time this added drag on the blades of more pitch, would also slow the rotor blades. That is why this exercise is critical to saving life, so has to be done at the right height and right amount to reduce descent rate to be survivable, but the helicopter has to have forward speed as well to help in all this.

The blades would work in the same way that the blades on an aurogyro copter would work to give it some lift as it moved down and forward through the sky. Since autogyros have no power going to the main rotor blade when flying, it is just blade angle plus angle of that sort of disk of the rotor blades to keep positive load on the blade disk and forward speed, provided by a pusher engine in a gyrocopter, that keeps it flying. If the collective is pulled too early, the rate of descent slows too early/high and the blades will slow down to the point of having no further lifting effect and then the copter just drops the rest of the way to the ground. Pulled too late and you don't arrest the descent speed in time and you impact the ground hard or very hard. So it is a very skilled thing to have to do, to get it right.

When you lose a tail rotor and part of that boom, things are very different and often or mostly, not survivable. As the body was spinning the blades were having less of an effect for autorotation plus things were getting very unstable and that is why it began to turn over and when the blades lost the positive loading, they would be bent from the airflow as it dropped and as you saw, would again impact the tail boom. Interesting that they seemed more or less intact, despite the tail boom having come apart. again not wanting to speculate but maybe the boom failed without an initial rotor impact, at the start of it all.

You might look up the specs on the R44, but I believe they only have two blades on the main rotor. What you might be seeing is the optical illusion from a camera shutter, making it look like it has four blades, just like a spinning wheel in the right lighting can often look like it is suddenly spinning backwards. I'm no expert on helicopters, so maybe a real helicopter pilot can jump in and give us some insight here. Again, it's best not to speculate on what happened, leave that to the expert investigators. I would like to know though, what was the initial cause of this failure and subsequence tragic accident.

I think you are right. I've been in front of an R44 and I think they do have only 2 blades. MD 500 the Mag Pi helicopter had 4 I think. It for sure was the tail rotor missing, but the rest of the boom after that. Tricky to get out of.

 

[svenf]

Us drones are not supposed to fly over people, but when things come undone, the helicopter just crashed into the ground below of wherever it happened to be at the moment. It caught on fire before hitting the ground causing it to freefall. It landed perfectly in the middle of an open field. Doubtful whether the pilot was able to place it there in the open space it landed in.

I'm convinced that helicopters will be replaced by drone-like aircraft in the future. The NTSB DB is full of helicopter crashes. They're harder to to control than fixed wing airplanes; it shouldn't have to be that way - it's an outdated aircraft design.

 

[Cymruflyer]

I'm convinced that helicopters will be replaced by drone-like aircraft in the future. The NTSB DB is full of helicopter crashes. They're harder to to control than fixed wing airplanes; it shouldn't have to be that way - it's an outdated aircraft design.

It's an amazing aircraft design and they are not necessarily harder to control but they do have more things moving around that can fail, than a fixed wing. A helicopter can autorotate down after an engine failure, current drones do not have that feature.

 

[-MavicMiniPilot]

Us drones are not supposed to fly over people, but when things come undone, the helicopter just crashed into the ground below of wherever it happened to be at the moment. It caught on fire before hitting the ground causing it to freefall. It landed perfectly in the middle of an open field. Doubtful whether the pilot was able to place it there in the open space it landed in.

Watch Dan Gryders YouTube video on this. This crash was caused by the main rotor hitting the tail or the chain system that spins the tail rotor coming undone from over speeding.

 

[svenf]

It's an amazing aircraft design and they are not necessarily harder to control but they do have more things moving around that can fail, than a fixed wing. A helicopter can autorotate down after an engine failure, current drones do not have that feature.

The fact that a helicopter can essentially knock itself out of the sky via boom strike is a design flaw that does not exist in a drone design. Obviously any drone for person transportation needs to be at least a hexcopter and as such in the event of one motor issue will be much safer to control than a heli on autorotation.

 

[Ty Pilot]

I'm convinced that helicopters will be replaced by drone-like aircraft in the future. The NTSB DB is full of helicopter crashes. They're harder to to control than fixed wing airplanes; it shouldn't have to be that way - it's an outdated aircraft design.

Are you suggesting all helicopters are 'outdated' designs or just the Robinson 44? I would say more demanding or perhaps less forgiving, but helicopters with their vertical TO capability are certainly not outdated. And if 'drone-like' aircraft ever become manned, I suspect they'll see a similar number of crashes and fatalities albeit from different types of mismanagement, rather than things like a tail strike.

 

[Cymruflyer]

The fact that a helicopter can essentially knock itself out of the sky via boom strike is a design flaw that does not exist in a drone design. Obviously any drone for person transportation needs to be at least a hexcopter and as such in the event of one motor issue will be much safer to control than a heli on autorotation.

It's a fact that a helicopter can not do what you suggest unless a careless pilot makes it do that. In the same way that a fixed wing aircraft can enter a stall, due to pilot error and possibly have the tail snap off after several rotations. Aircraft are only as safe as the person flying it.

Don't get me wrong, I'm a pilot since the 70s and a long time flight instructor, I cant wait for a safe flying person carrying drone type aircraft. However they will never come up to the long range and lifting power that a standard helicopter currently offers. I do hope we see person carrying drone while I'm still young enough to fly one. Though they will probably be out of my budget by then.

 

[svenf]

It's a fact that a helicopter can not do what you suggest unless a careless pilot makes it do that. In the same way that a fixed wing aircraft can enter a stall, due to pilot error and possibly have the tail snap off after several rotations. Aircraft are only as safe as the person flying it.

Don't get me wrong, I'm a pilot since the 70s and a long time flight instructor, I cant wait for a safe flying person carrying drone type aircraft. However they will never come up to the long range and lifting power that a standard helicopter currently offers. I do hope we see person carrying drone while I'm still young enough to fly one. Though they will probably be out of my budget by then.

A heli can be stalled just like an airplane can be stalled by operating error - the difference I'm talking about is a design that generally allows the rotating blades of a helicopter to cut off its own tail. I have no idea if that applies to few, many or all helicopters, but I find that shocking.
The simpler drone-based multicopter design is just much better the way I see it because you can have a much higher level of redundancy. Range is still a big issue with batteries, but a hybrid combination can (and likely will ) address that.

 

[svenf]

Are you suggesting all helicopters are 'outdated' designs or just the Robinson 44? I would say more demanding or perhaps less forgiving, but helicopters with their vertical TO capability are certainly not outdated. And if 'drone-like' aircraft ever become manned, I suspect they'll see a similar number of crashes and fatalities albeit from different types of mismanagement, rather than things like a tail strike.

The R44 may be even worse than other helicopters, but all of them are outdated design in my opinion.
I wholeheartedly disagree with your assessment that drone-type multicopter aircraft will get to see accident rates anywhere near fixed-wing airplanes or helicopters (which have an even higher accident rate than fixed-wing), simply because it's a much newer combination of technological evolution and higher redundancy.

 

[lookout]

It's a fact that a helicopter can not do what you suggest unless a careless pilot makes it do that. In the same way that a fixed wing aircraft can enter a stall, due to pilot error and possibly have the tail snap off after several rotations. Aircraft are only as safe as the person flying it.

Don't get me wrong, I'm a pilot since the 70s and a long time flight instructor, I cant wait for a safe flying person carrying drone type aircraft. However they will never come up to the long range and lifting power that a standard helicopter currently offers. I do hope we see person carrying drone while I'm still young enough to fly one. Though they will probably be out of my budget by then.

Hovercraft was about the closest to that some years ago. But the problem was...where are the brakes?

 

[Cymruflyer]

The R44 may be even worse than other helicopters, but all of them are outdated design in my opinion.
I wholeheartedly disagree with your assessment that drone-type multicopter aircraft will get to see accident rates anywhere near fixed-wing airplanes or helicopters (which have an even higher accident rate than fixed-wing), simply because it's a much newer combination of technological evolution and higher redundancy.

You need to keep in mind that control of GA aircraft, fixed and rotor wing, the control mechanism is mechanical, and parts are lifed and inspection can be carried out by the eye and under microscopes. The control system for a drone type flying machine is all electronic and we know that failures do occur and there is nothing to inspect in an electronic system. You just have to hope that the programmers did things correctly and none of the electronics will fail. There lies the difference between the two.

 

[Cymruflyer]

Hovercraft was about the closest to that some years ago. But the problem was...where are the brakes?

Brakes on a hovercraft were drag from the skirt and reverse the direction and applying power. A good friend build hovercraft for years, I had two 2-seaters years back. However, they only float a few inches off the ground and the draggy skirt must always be in contact with the ground to keep that lift bubble in place, so they are no different to a car in reality, regarding flight, that is. Though, they were fun to play around with.