RAF Helicopter Crash
If the TR had hit first whilst still being driven, it would have disintegrated and the tail would have probably been twisted off. It looks more like a heavy landing with a fair amount of sideways drift which snapped the tail wheel and broke the spine - then the TR impacted after the drive had severed.
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Lossie Sea King crash
Seeing the pictures of a yellow Sea King in kit form certainly took me back! Been there, done that, got the T-shirt (and brown trousers). Glad I'm now retired, but I understand everyone walked away, so nice one! Cherish the tick in the box!
GeeRamps, KOS
GeeRamps, KOS
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Actually, Crab, think you might have a point now the other photos are availble. Which shows why we shouldn't speculate but wait for the real answer I suppose.
So, what do you reckon happened then?
So, what do you reckon happened then?
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I got sent this by a friend who has S-61 time and thought I'd post it to see what folks make of it.
Some observations based on the photographs:
1. The tail rotor was spinning when it hit the ground. It is impossible to tell at what RPM it was spinning upon contact... my guess is that it was decreasing or winding down.
2. The tail pylon damage is not consistent with a main rotor blade (MRB) strike.
The location on the tail pylon would have required contact at mid-span (on the MRB) vice the tip which would be unusual. Additionally, none of the MRBs appear to have damage.
The tail drive shaft cover has separated cleanly as opposed to being "chopped."
The pylon, itself, shows tearing at the top with wrinkling on the bottom (tensile mode of failure?) along with a horizontal bending moment to the left or port side of the aircraft.
3. The tail wheel has been severely deformed and displaced to the right indicating a possible left drift or clockwise yaw.
4. Different photo aspect shows initial tail wheel contact on runway delineated by puddle of fluid, ostensibly from the strut cylinder. Additionally, skid marks from tail wheel assembly indicate a left and back drift prior to coming to a stop.
Suppositions:
Aircraft was probably in a hover at onset of failure.
Engine failure unlikely culprit as these well-trained blokes would have set her down with little or no lateral drift or yaw.
Possible villains:
(1) Loss of tail rotor drive - one of the few emergencies in a twin that requires immediate action. Impetus would be to get aircraft on the ground before spin accelerated. Hard landing would be warranted with vertical component strong enough to tear tail pylon off. Residual tail rotor RPM would cause all five T/R blades to bend even if not being mechanically driven.
(2) Loss of tail rotor control (stuck pedal equivalent) - not quite as bad as loss of drive - can actually be flown in certain flight regimes, but in a hover it would be nearly as nasty as loss of drive.
(3) Assuming the hydraulic system in the British Sea King is similar to the Yank version... it could have been an auxiliary hydraulic hardover in the yaw channel which requires rapid corrective action (securing aux hydraulic system, if memory serves). Diagnosis would be problematic in a hover as there's less time before onset of a high yaw rate.
Bottom line: The fact that the lads kept it right side up and the crew was able to sprint for the nearest exit attests to the best possible outcome under the circumstances.
1. The tail rotor was spinning when it hit the ground. It is impossible to tell at what RPM it was spinning upon contact... my guess is that it was decreasing or winding down.
2. The tail pylon damage is not consistent with a main rotor blade (MRB) strike.
The location on the tail pylon would have required contact at mid-span (on the MRB) vice the tip which would be unusual. Additionally, none of the MRBs appear to have damage.
The tail drive shaft cover has separated cleanly as opposed to being "chopped."
The pylon, itself, shows tearing at the top with wrinkling on the bottom (tensile mode of failure?) along with a horizontal bending moment to the left or port side of the aircraft.
3. The tail wheel has been severely deformed and displaced to the right indicating a possible left drift or clockwise yaw.
4. Different photo aspect shows initial tail wheel contact on runway delineated by puddle of fluid, ostensibly from the strut cylinder. Additionally, skid marks from tail wheel assembly indicate a left and back drift prior to coming to a stop.
Suppositions:
Aircraft was probably in a hover at onset of failure.
Engine failure unlikely culprit as these well-trained blokes would have set her down with little or no lateral drift or yaw.
Possible villains:
(1) Loss of tail rotor drive - one of the few emergencies in a twin that requires immediate action. Impetus would be to get aircraft on the ground before spin accelerated. Hard landing would be warranted with vertical component strong enough to tear tail pylon off. Residual tail rotor RPM would cause all five T/R blades to bend even if not being mechanically driven.
(2) Loss of tail rotor control (stuck pedal equivalent) - not quite as bad as loss of drive - can actually be flown in certain flight regimes, but in a hover it would be nearly as nasty as loss of drive.
(3) Assuming the hydraulic system in the British Sea King is similar to the Yank version... it could have been an auxiliary hydraulic hardover in the yaw channel which requires rapid corrective action (securing aux hydraulic system, if memory serves). Diagnosis would be problematic in a hover as there's less time before onset of a high yaw rate.
Bottom line: The fact that the lads kept it right side up and the crew was able to sprint for the nearest exit attests to the best possible outcome under the circumstances.
Aircraft was on a test flight to try to establish cause of vibrations, source ARCC.
Pure speculation but.....
In the hover at ?ft. Tail rotor drive failed, check the piccies, sheared trds, a pretty clean break at that. No sign of bending which would be expected if it had broken when the pylon became detached.
Theory, tail rotor drive shaft hangar bearing failed/seized, shaft overheated and sheared, the rest is history. The only direction you are going, or would wish to go after that is downwards, quickly!
As I say, pure speculation. But this is a rumour network after all!!
A question though. Do Sea Kings have IHUM's or equivalent fitted? I presume that is not a state secret.
The guys in this machine did well to be able to walk away, although I suspect it was a case of drop the lever and hang on... B.Z.
I am sure crab will have some thing to say?
Pure speculation but.....
In the hover at ?ft. Tail rotor drive failed, check the piccies, sheared trds, a pretty clean break at that. No sign of bending which would be expected if it had broken when the pylon became detached.
Theory, tail rotor drive shaft hangar bearing failed/seized, shaft overheated and sheared, the rest is history. The only direction you are going, or would wish to go after that is downwards, quickly!
As I say, pure speculation. But this is a rumour network after all!!
A question though. Do Sea Kings have IHUM's or equivalent fitted? I presume that is not a state secret.
The guys in this machine did well to be able to walk away, although I suspect it was a case of drop the lever and hang on... B.Z.
I am sure crab will have some thing to say?
Of course I will 3D - the ARRC are incorrect, the aircraft had been on a vib 6 test flight earlier in the day and had passed. Then the crew took it for a role trip on which it crashed shortly after take-off. I will not speculate about what happened since a. I have a pretty good idea from information received anyway and b. there is a BOI convened which will report in due course.
However, despite your assertion that it was a mechanical failure, the fleet is not grounded, nor has it had any STI raised to check TR shafts and bearings. As a precaution, the RAF SARF went to ops only for less than 48 hours to wait for the BOI's 48 hr signal. The RN didn't even do that. The only advice for the meantime is not to do damper checks. Draw your own conclusions.
However, despite your assertion that it was a mechanical failure, the fleet is not grounded, nor has it had any STI raised to check TR shafts and bearings. As a precaution, the RAF SARF went to ops only for less than 48 hours to wait for the BOI's 48 hr signal. The RN didn't even do that. The only advice for the meantime is not to do damper checks. Draw your own conclusions.
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With absolutely no background in Sea Kings or accident investigation, but a couple of glasses of wine to sharpen my ESP...
Tail rotor driveshaft or txmsn failure (clean driveshaft break, oil out of T/R housing vent), right yaw develops, pilot puts it DOWN. Note position of tail wheel, pylon, and relative lack of damage to T/R blades (considering they are holding the pylon up).
Good on 'em for getting it down with nobody hurt, and someday we'll know what actually happened.
Tail rotor driveshaft or txmsn failure (clean driveshaft break, oil out of T/R housing vent), right yaw develops, pilot puts it DOWN. Note position of tail wheel, pylon, and relative lack of damage to T/R blades (considering they are holding the pylon up).
Good on 'em for getting it down with nobody hurt, and someday we'll know what actually happened.
