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In my opinion, all that one can tell from that photo is that there has been a catastrophic, and very sad, helicopter crash. That's what the AAIB are for.
That 'device' is nothing more than a cover, or cap, for where the duplex bearing is housed. |
nodrama, thanks for clarification...
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How robust is this spider and duplex bearing?
separate component or integral with the TGB? what's its overhaul life and inspection schedule? greased bearing or oil supplied from TGB? c'mon nodrama, if you're experienced, share and educate. |
The nice thing, with a tail rotor failure in hoover or low speed is that you DIRECTLY and FIRST OF ALL goes for an autorotation by lowering the collective all the way to the lower stop. You don’t need to think if a cotter pin, a nut or all the tail rotor blades are missing. You -bang!- go for autorotation. If this accident was a tail rotor drive failure you had to land immediately, even if in trees, but here you had a few options like open areas where you probably could make a survivable ”landing".
Look at tailrotor failures like this: If you hesitate to go in autorotation you are toasted, but if you go in to a autorotation and it shows wrong, you can always change your mind. To survive a helicopter, always think negative for a positive outcome. The different types of tail rotor failures and necessary actions taken are well known and are described in all helicopter manuals |
Arizona, your answer is too simplistic and unfortunately doesn't take into account that not all tail rotor malfunctions involve a loss of drive/thrust.
In the situation where the tail rotor continues to be driven but pitch control is lost and the tail rotor goes to maximum positive pitch, entering auto-rotation might be the last control input you ever made. |
Shy, I am reminded of an old aphorism (maybe from Einstein) that a great many complex problems have simple, clear, and wrong answers. (ref to what you responded to) :cool: I'm with you; an incorrect response to a particular malfunction can make things worser faster.
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Blimey, this is still rumbling on.......
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Crab, simply as a matter of interest and as I have easy access to a Level D 139 FFS, I had a go yesterday at using the technique discussed by you and DB. Even in the sim, and I knew it was coming, I very quickly became disorientated. I even found it difficult to take my hand off the collective to kill the engine mode switches. I felt I had no control whatsoever of the helicopter and was just along for the ride. No real thanks to me, the sim helicopter did remain level and I eventually put the collective down quickly. I got away with a successful level, spinning landing but I was very surprised at how quickly I lost all references. I carried out this exercise from 20 ft. From 400 feet I have absolutely no doubt it would be impossible. IMHO and as we seem to all agree, those poor guys didn't stand a chance.
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Originally Posted by hihover
(Post 10321863)
Crab, simply as a matter of interest and as I have easy access to a Level D 139 FFS, I had a go yesterday at using the technique discussed by you and DB. Even in the sim, and I knew it was coming, I very quickly became disorientated. I even found it difficult to take my hand off the collective to kill the engine mode switches. I felt I had no control whatsoever of the helicopter and was just along for the ride. No real thanks to me, the sim helicopter did remain level and I eventually put the collective down quickly. I got away with a successful level, spinning landing but I was very surprised at how quickly I lost all references. I carried out this exercise from 20 ft. From 400 feet I have absolutely no doubt it would be impossible. IMHO and as we seem to all agree, those poor guys didn't stand a chance.
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Sure, I agree, simulation has limitations, it was a different type from your student, and not even a 169. My point is simply that, after 40 years and 14,000 hours in the game, and being ready for the exercise, and having been in a helicopter with a tail rotor failure, I found it quite impossible to accept the rate of yaw with any form of control. I would need much more spare capacity.
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Meanwhile...back to pointless speculation. Nodrama states that 'The aircraft that is the subject of this thread had flown less than 400 hours.'. Apologies if this has been stated elsewhere and I've missed it but what maintenance inspections would it therefore have been subject to since being built in 2016? - and would any of these inspections specify detailed examination of the tail rotor parts that are the subject of the AD notices as discussed above?
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HiHover - I didn't say it would work but compared to a zero speed auto to EOL from 400' it might be the lesser of two evils:ok:
Perhaps the entering auto but keeping the engines running and using them to cushion the touchdown - if you can judge it - might be a refinement of the idea. Either way I am in no rush to try it out! |
You could be right mate. I was just astounded at how little control I had in trying to keep her level and reduce the yaw rate.
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The beauty of the Sim is you can try it over and over and crash repeatedly....and at some point call it a day and head for a Pint on wobbly legs!
the IAF lost a Bell 212 (or 412 maybe) after a Pilot had picked up way too heavy a load on the Hoist....and came to our Facility to see if they could replicate the event. I played with the Lateral CG Parameters to arrive at their calculated data and after about a dozen or so attempts we actually got to where we could fly out of the situation by using some very un-unorthodox control techniques which were quite counter-intuitive. A large police department aviation unit came to us and wanted to practice autorotations and tail rotor failures at various HOGE heights....and we found that to be very interesting as well. Whether the actual aircraft would react exactly as the Sim (or conversely....) was not the point of the exercises but determining what actions improved the situation was. One thing for sure....we could prove certain actions were very bad juju and immediately made certain situations absolutely uncontrollable. Get back in your box of tricks and experiment.....just do not activate your "Crash Over-Ride" as even a Sim can hurt you if left to its own. |
:) No thanks SAS, I’ve seen enough. Unfortunately, when faced with an issue that requires immediate action, we revert to basic mode and we generally deliver whatever our survival instincts think we should. I can’t think of a worse position to suffer a catastrophic tail rotor issue. |
hihover
I can’t think of a worse position to suffer a catastrophic tail rotor issue. |
Originally Posted by hihover
(Post 10322454)
:) No thanks SAS, I’ve seen enough. Unfortunately, when faced with an issue that requires immediate action, we revert to basic mode and we generally deliver whatever our survival instincts think we should. I can’t think of a worse position to suffer a catastrophic tail rotor issue. |
Originally Posted by DOUBLE BOGEY
(Post 10322465)
HiHover, what is your view of the Landing Gear being raised prior to the TDP?
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Originally Posted by chopjock
(Post 10322461)
hihover
And they were put in that position by the regulations in the name of safety... |
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