Loss of tail rotor

melax said:
That's a scary video !
I'm wondering if it's due to mast bumping ? apparently the R44's are prone to it.
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RIP
We used to joke that there wasn’t such an event. There could be a mast ”BUMP”, but not bumping.

A mast bump would have damaged the mast and perhaps separated the main rotor. They do have a problem with this.
These Robinson are very susceptible to tail boom strikes in negative G maneuvers too. The SFAR was written for these issues. I had a fellow officer and his fiancé (on the way to meet the parents) die in a crash because if this.

Not stating that they were flying out of the limits but high winds/turbulence can get you there pretty quickly. Could be an out of balance tailrotor, bird strike, material failure, etc…to early
 
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The video is terrifying.

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Oxman said:
I always thought I wanted to get dual rated. Then I saw an R44 practicing auto rotations at the airport. I changed my mind.
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I had a similar reaction watching what-I-think-was-a-Schweitzer doing the same thing one day.

I know it's a non-issue if you know what you're doing. When you don't, it looks like black magic and luck.
 
killbilly said:
I had a similar reaction watching what-I-think-was-a-Schweitzer doing the same thing one day.

I know it's a non-issue if you know what you're doing. When you don't, it looks like black magic and luck.
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Depending on the helicopter, even if you know what you’re doing it's black magic and good luck!
 
melax said:
That's a scary video !
I'm wondering if it's due to mast bumping ? apparently the R44's are prone to it.


www.dailymail.co.uk

Grim footage shows helicopter tumbling to earth in Dallas

The helicopter crashed about 11.30am into a vacant lot on a busy commercial strip along Texas 66 in Rowlett, killing the pilot and another person on board, but leaving no else injured.
www.dailymail.co.uk www.dailymail.co.uk

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I thought "mast bumping" was a cyclic hardware contacting the mast issue, and not being knowledgeable, i simply looked at a video

Just looking at a R-44 sitting next to my plane right now, I'm not sure if it is even the design that would allow that at all.
Some kind of contact with boom, I have no idea if that is among the possibilities.
rough video to watch
 
dustoff17 said:
Depending on the helicopter, even if you know what you’re doing it's black magic and good luck!
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Any questions?

When I was a student pilot, a Navy Chopper pilot was getting checkout in the schools complex aircraft. When he passed me on the ramp he turned a said; Not enough moving parts.
 
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mightynimbus said:
I thought "mast bumping" was a cyclic hardware contacting the mast issue, and not being knowledgeable, i simply looked at a video

Just looking at a R-44 sitting next to my plane right now, I'm not sure if it is even the design that would allow that at all.
Some kind of contact with boom, I have no idea if that is among the possibilities.
rough video to watch
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Interesting read:

verticalmag.com

Undetermined Reasons

More than 20 years after the U.S. National Transportation Safety Board launched a special investigation into loss of main rotor control accidents in Robinson helicopters, fatal in-flight breakups continue to happen — and we can’t fully explain why.
verticalmag.com verticalmag.com

Robinson helicopters: mast bumping accidents in NZ | TAIC

THIS IS A LEGACY PAGE, SUPERCEDED IN 2024 BY THE TAIC WATCHLIST 2024. FOR THE CURRENT WATCHLIST, PLEASE SEE https://www.taic.org.nz/watchlist
www.taic.org.nz www.taic.org.nz
 
So called mast bumping is something only possible in semi-rigid, or teetering, two-blade main rotor system designs such as the UH-1 and Bell 206 and Robinsons. It’s something that has to be taken into account with these systems, but that said, when a semi-rigid system is flown within its parameters…..ie- no negative Gs, they’re fine. They’ve been around for decades. Mast bumping isn’t possible in other rotor systems types. The biggest thing that gets guys in trouble in these systems is moving the cyclic when there’s any negative G….versus placing even the smallest of positive G on the bird first before moving the cyclic. That way the fuselage of the helo and it’s attached mast, doesn’t move underneath the underslung components of the rotor system and contact them. Versus with positive G, the fuselage reacts opposite the direction of applied cyclic due to centrifugal force.

In the video of this accident, this doesn’t appear to be a mast bump, as the rotor system is intact as the helo is initially spinning. Something appears to have occurred with the tail rotor or gearbox.
 
melax said:
Interesting read:

verticalmag.com

Undetermined Reasons

More than 20 years after the U.S. National Transportation Safety Board launched a special investigation into loss of main rotor control accidents in Robinson helicopters, fatal in-flight breakups continue to happen — and we can’t fully explain why.
verticalmag.com verticalmag.com

Robinson helicopters: mast bumping accidents in NZ | TAIC

THIS IS A LEGACY PAGE, SUPERCEDED IN 2024 BY THE TAIC WATCHLIST 2024. FOR THE CURRENT WATCHLIST, PLEASE SEE https://www.taic.org.nz/watchlist
www.taic.org.nz www.taic.org.nz
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I’m more convinced than ever that no one REALLY knows how helicopters fly.
 
melax said:
Interesting read:

verticalmag.com

Undetermined Reasons

More than 20 years after the U.S. National Transportation Safety Board launched a special investigation into loss of main rotor control accidents in Robinson helicopters, fatal in-flight breakups continue to happen — and we can’t fully explain why.
verticalmag.com verticalmag.com

Robinson helicopters: mast bumping accidents in NZ | TAIC

THIS IS A LEGACY PAGE, SUPERCEDED IN 2024 BY THE TAIC WATCHLIST 2024. FOR THE CURRENT WATCHLIST, PLEASE SEE https://www.taic.org.nz/watchlist
www.taic.org.nz www.taic.org.nz
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Thanks,
I know very little about this topic.
 
About a decade ago a similar accident took place at my airport during the takeoff sequence when the fuel cap liberated itself and went through the tail rotor. They made a couple of uncontrolled rotations from the torque and had an eventful uncontrolled landing without injuries.

Hard to imagine the fuel cap departed in cruise but something happened that led to loss of tail rotor effectiveness (LTE).
 
melax said:
Like the main rotor blades contacting the tail boom ? :eek:
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appears to have come after the initial spin.

if the tail gearbox separated, the pilot has to autorotate and get the engine shut off to avoid a spin or minimize any spin that has already occurred. And while doing that, keep the bird as level as possible with only controller turns and no gyrations….sometimes easier said than done. That would already be a challenge because with the loss of the tail rotor and/or gearbox, there’d be a marked forward CG shift to overcome. If the helo isn’t kept somewhat level/upright in an autorotative descent, and especially with a helo equipped with a 2-blade semi-rigid rotor system, any max deflection of the rotor disc by the pilot with the cyclic stick, makes blade flex a high possibility along with the movement of the rotor system itself, resulting in a high probability of chopping the tailboom off the bird. At that point, the bird and anyone in it, is done, as the rest of the helicopter disintegrates on its way down to earth like a rock. At the end of the day, physics always wins.
 
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