Bye bye tail rotor.
- Thread starter Makinchips208
- Start date
There is another much clearer video out there which appears to show a possible pitch link failure for one of the tail rotor blades which then sets the whole sequence of events off; with intact and unburned wreckage plus multiple videos I'm confident the FAA will come up with a definitive cause. Sometimes video compression artifacts mess with things, so I'll put what appears to be a pitch link failure in the video down as a possibility and wait for the official accident report. But in the mean time we'll gets lots of speculation from expert internet accident investigators.
Pilot appeared to be solidly in the dead man's curve of the H/V diagram when things went sideways and didn't have many options, things could have ended up much worse than they did for both the people in the helicopter as well as those on the ground.
Pilot appeared to be solidly in the dead man's curve of the H/V diagram when things went sideways and didn't have many options, things could have ended up much worse than they did for both the people in the helicopter as well as those on the ground.
From what I read there were no fatalities. A poor kid on the ground was injured pretty bad, brain bleed or something. Sounded serious.
I've watched that video and what I can't figure out is why the big power pull?? Seems like he was close to landing when shit went sideways. I was thinking tail rotor strike but still seems odd he climbed like he did. I'm a fixed wing guy....so idk all the procedures.
My bet is on tail rotor gearbox (most likely) or driveshaft failure.
The video shows that the tail rotor changed speed substantially at the same time the yaw started. Normally, main rotor and tail rotor are coupled via a power tap on the main rotor gearbox, a rigid driveshaft inside and along the length of the tail boom and a 90 degree gearbox at the end of the tail boom. Which means that the tail rotor cannot change rpm independently from the main rotor unless there is a failure in the drive train.
A failure affecting only the pitch control of the tail rotor would also have resulted in an uncommanded yaw but would NOT have caused a sudden change in tail rotor rpm.
Disclosure: I work for a helicopter manufacturer but have not stayed at a Holiday Express recently.
The video shows that the tail rotor changed speed substantially at the same time the yaw started. Normally, main rotor and tail rotor are coupled via a power tap on the main rotor gearbox, a rigid driveshaft inside and along the length of the tail boom and a 90 degree gearbox at the end of the tail boom. Which means that the tail rotor cannot change rpm independently from the main rotor unless there is a failure in the drive train.
A failure affecting only the pitch control of the tail rotor would also have resulted in an uncommanded yaw but would NOT have caused a sudden change in tail rotor rpm.
Disclosure: I work for a helicopter manufacturer but have not stayed at a Holiday Express recently.
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Based on the video it sure appears to initially be a failed or disconnected pitch change link that is swung outwards by centripetal force, followed by tail blade pitch asymmetry as at that point one blade is still connected and controlled as normal while the other will take a neutral aerodynamic position, and then the vibrations and forces from that thrust imbalance caused a tail gearbox failure including separating it from the airframe. In one of the videos you can see the gearbox detach and get flung towards the person taking the video and then landing in the parking lot.
And as an added bonus we get to see the results of mast bumping captured on fairly clear video.
Again... the video is pretty damning, but I'll wait until the initial incident report comes out, hopefully with pictures of the tail rotor components.
I wonder how many affirmative action hires were flying or maintaining the aircraft.
or making/inspecting the parts?
"Uh, yup... there's a 'something' in that box.... ship it!"
Is he already struggling with issues on the approach? He's "crabbing" coming in, but for any reason? The trees don't seem to be moving so I don't think it's that windy?
Was always a little nervous flying in helicopters back in the day. Those things don’t want to fly in the first place , as opposed to fixed wing, and you have to make them do it. Therefore, they’re not very tolerant of anything at all going wrong,
It was a choppers and cars event. Had several friends there. Everyone survived, but the video of the boy on the stairs was hard, poor kid.
Kid was very lucky, the engine exhaust was fortunately not blowing on him cause it kept running after the crash, you can briefly see the main rotor shaft is still spinning away. VERY lucky there was no fire, that would have been a lousy way to go.
Pilot pulled up hard on the collective, putting a hell of a load on the engines, you can see condensation forming on the trailing edge of the main rotor blades, along with some smoke from the engines from the high loads, not thick like rolling coal, but it's there, he was climbing hard.
I'm not a pilot, no formal training, I have watched several youtube videos, but I would have thought that the procedure for a tail rotor failure when you're that close to the ground would be to preferably get on the ground as controlled as you can, rather than gain altitude. Hopefully someone that's an actual helo pilot can come in here and tell me i'm a dumb dumb and command me to sit in the corner and think about my stupid thoughts.
Heli pilot (well, kinda former) here. You’re not a dumb dumb, nor are you wrong. It’s somewhat complex to describe in detail here, but the short version is that in the event of a tail rotor failure, the proper response is to enter an autorotation. The reason for this is fairly straightforward: entering an auto removes power from the main rotor system, eliminating torque and the need for tail rotor control to counteract said torque.
The issue in this case is that entering an auto at that altitude and that airspeed (low/slow) makes for an incredibly difficult maneuver to pull off successfully. In something like the Bell 222 in the video, you’d still have a decent amount of inertia in the rotor system (those blades are hella big/heavy), but he appeared to still be over trees when it happened and he would have settled very quickly. Chances are they would have come straight down into the trees, destroying the rotors and therefore eliminating any chance of cushioning the landing by pulling collective. In a vertical orientation like that, that would likely have meant severe spinal compression for all involved, likely fatal.
So while him pulling collective to gain altitude made the situation “worse” by adding MORE torque and thus causing the total tail rotor failure and hard right spin shown, in a weird way it may have saved their lives as a crash-landing on their side was probably less damaging to them than a near vertical one.
But you’re correct. In most (all?) helicopters, a total tail rotor failure would involve a full-down autorotation as essentially no torque is needed when the rotor is unpowered. Again, very difficult to do at that altitude/airspeed combo (I don’t know the Bell 222’s performance charts, but he’s very likely within the shaded “avoid” area of the height/velocity diagram), but that’s helicopters for you. Sometimes you have to learn to fight what seems like a natural/correct response as they’re inherently unstable machines. Absolutely amazing when they work properly, and devastating when they don’t.
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