PILOT SPIN
Pilot Zone => Accident Review/Never Again (I hope..) => Topic started by: Rush on April 10, 2025, 02:49:54 PM
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I heard 6 dead, a couple from Spain with their 3 children and the pilot. Seems the tail is missing. I wonder what happened.
https://x.com/Bubblebathgirl/status/1910426645002846309
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Max Trescott was guessing the main rotor cut the tail boom off due to a sudden cyclic movement. I emphasize guessing.
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That's really sad.
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Max Trescott was guessing the main rotor cut the tail boom off due to a sudden cyclic movement. I emphasize guessing.
I saw that. i had no idea that could happen. But I know nothing about helicopters.
I asked Grok:
The Hudson River helicopter crash on April 10, 2025, involved a Bell 206L-4 LongRanger, and reports suggest a catastrophic failure where the main rotor and tail boom separated mid-flight, leading to the tragic loss of all six onboard. The theory you mentioned—about the main rotor striking the tail boom, causing it to break off—has been discussed in aviation circles and aligns with some witness accounts and early analysis of this incident. Let’s break it down.
Yes, a main rotor striking the tail boom is possible, though rare, and it’s not a design flaw but a consequence of extreme conditions or mechanical failure. This phenomenon is often linked to something called "mast bumping" or excessive rotor blade flapping, where the main rotor’s motion becomes so erratic that it contacts the helicopter’s body, including the tail boom. In the case of the Hudson crash, witnesses described the helicopter "falling apart" with the tail and rotor detaching, and some experts speculated the main rotor may have sliced the tail boom, causing the cabin to free-fall.
Why does this happen? Helicopters like the Bell 206 use a semi-rigid rotor system, which allows the blades to flap up and down to adjust to aerodynamic forces. Under normal conditions, this keeps the helicopter stable. But in extreme situations—say, severe turbulence, a sudden gust, pilot error, or a mechanical failure like a loss of tail rotor control—the rotor disc can tilt excessively. If the blades flap too far, they can strike the tail boom, which is catastrophic because it severs critical structural and control components. The tail rotor, vital for counteracting the main rotor’s torque, is mounted on the tail boom, so if the boom is destroyed, the helicopter spins uncontrollably and loses lift.
The comment about “extreme winds” or a “big gust” could be relevant. Weather reports from the crash noted winds of 10-15 mph with gusts up to 25 mph. While not extreme for most aircraft, a sudden gust could exacerbate an existing issue, like a tail rotor malfunction or pilot overcorrection, especially in a low-altitude urban environment with turbulent airflows. However, gusts alone are unlikely to cause a rotor strike without another underlying factor, as helicopters are designed to handle typical wind conditions.
The mention of Robinson helicopters is worth addressing. Robinsons, like the R22 and R44, have a history of mast bumping incidents, particularly in low-G conditions (like pushing the nose down too fast), because their lightweight, teetering rotor systems are more sensitive to abrupt control inputs. Bell helicopters, including the 206, are generally sturdier, with a reputation for reliability in commercial ops like sightseeing. But no helicopter is immune to physics—if the rotor system is pushed beyond its limits, a strike can happen. The Bell 206’s design doesn’t “allow” the rotor to whip the tail off; rather, it’s a failure mode when something goes very wrong.
Could it be a design flaw? Not really. Helicopter rotor systems are engineered with safety margins, but they operate under intense aerodynamic and mechanical stresses. Designing a rotor that could never strike the airframe would likely make the helicopter too heavy or rigid to fly efficiently. Instead, pilots are trained to avoid conditions that could lead to excessive blade flapping, and maintenance is critical to ensure components like the tail rotor drive shaft (which had a 2023 directive for Bell 206 models due to a prior failure) are sound.
So, is the theory plausible? Yes, it’s consistent with known failure modes and the crash’s reported details—main rotor detachment, tail boom severance, and rapid loss of control. But why it happened isn’t clear yet.
Possibilities include:
Mechanical failure: A tail rotor or drive system failure could cause the helicopter to yaw uncontrollably, leading to rotor misalignment and a strike.
Pilot input: An overcorrection in turbulent conditions might have pushed the rotor disc too far.
External factors: A gust or even a bird strike (though less likely) could have compounded an issue.
Structural issue: Fatigue or an undetected defect in the rotor hub or tail boom, though Bell 206s have a strong safety record.
The “Ranger” mention in the theory likely refers to the Bell 206L LongRanger, the model involved, not a Robinson. Robinson helicopters aren’t directly comparable here—different design, different dynamics. As for “whipping,” it’s not that the blades are designed to whip around chaotically; it’s that in a failure state, the rotor’s momentum and flexibility can lead to destructive contact.
Without the NTSB’s final report, which will analyze the black box, wreckage, and pilot records, we can’t pin it down. My take: the main rotor striking the tail boom is a credible scenario based on past incidents and eyewitness reports, but it’s not “common” for Bells, and wind alone probably didn’t cause it. Something—mechanical, human, or both—likely set the stage for this disaster.
If you’re curious about specific Bell 206 incidents or want me to dig deeper into rotor dynamics, let me know!
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Family ID’ed:
https://x.com/ChillinEffect/status/1910653592274690157
I can’t imagine the horror, but I did, every time my husband and I put our kids in a small plane and flew around, I was all too aware of the possibility of us all being wiped out together.
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Family ID’ed:
https://x.com/ChillinEffect/status/1910653592274690157
I can’t imagine the horror, but I did, every time my husband and I put our kids in a small plane and flew around, I was all too aware of the possibility of us all being wiped out together.
Were you ever aware of the same possibility when you put your family in a car and got on the expressway? Or even just around town?
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Were you ever aware of the same possibility when you put your family in a car and got on the expressway? Or even just around town?
Absolutely. But the statistical odds are very different. There is a high likelihood not everyone in the car will die in any one crash. Most likely will be at least one survivor to carry on the genes.
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Looks like the rotor, transmission, and most of the engine separated before the tail fell off. Constant flight in a salty environment... bad maintenance and the engine mount bolts failed?
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Looks like the rotor, transmission, and most of the engine separated before the tail fell off. Constant flight in a salty environment... bad maintenance and the engine mount bolts failed?
Wow. That wouldn’t even have occurred to me.
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More than likely the tailboom separated first, and the resultant forces ripped the mast and the rotor blades off.
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Catastrophic transmission failure?
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Catastrophic transmission failure?
No, if that happened the MR would freewheel due to the sprag clutch so it would be able to autorotate.
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Interesting analysis, he leans to mast strike though not conclusively:
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Preliminary report. Enhanced blurry pics seem to show tail separating first.
https://t.co/jjGb6aSrP9