Re possible swashplate failure: We suffered one of those in 1996 with the first hover of a production 53E. High hover. Swashplate bearing failed-quick overheat and rotating part of swashplate slowed down, dragging all pitch links-blades cut tail off and basically fell in from 200+ ft. It did immediately catch fire but the crash crew was on it in 38 seconds.
This CH-47 video is a bit different. I did notice the aft rotor seemed to have a bunch of conning as it got closer to the ground and the front not so much, yet the pitch attitude wasn’t far off level, so my visual assessment is contradictory. What does seem to say “ controls “ is that they didn’t punch off the bucket.
Just out of flight school and landing a UH-1D on the pad called Chinook Hill on the north side of Cairns, one of our CH-47 initial pre-production machines suffered “ floating SAS links “, but that created an exceedingly wobbly ( pitch, roll and yaw excursions ) hover, which they finally lost and it hit on its side. All walked away. Again, a very different failure flight path.
We also had a aft transmission output bearing failure, but the crew got it back to Cairns and landed on the north sod. That made some smoke.
None of these point a finger on the subject event here. The only good aspect is that the wreckage looks to be all there and not burned, so the failure mode ( and I’d side with your mechanical assessment ) should be accessible. That the yaw axis ( and vertical ) was abnormal, but not pitch nor roll is the first place to look. The yaw rate was enough to dis-orient somewhat, but I’m thinking that they had to be applying high forces to increase collective before they hit, yet the video did not reflect any of that. So: control jam suggests itself as a possibility.
Hope they get some expert help in looking thru the control system. We had a UH-60A fatal at Ft Bragg that took just over 6 months before finding the missing* part ( and related maintenance error-safety missing )
*Against protests that it wasn’t necessary, that the initial metal detector search was beyond thorough in the first place, the H-60 Engr Chief forced a repeat search, which found the nut 4 ft or so buried in the ground.
By now, I bet someone has taken out a CH-47-come to a hover at say 250 ft-made a 1-2 inch left pedal input while keeping the other controls fixed, and observed the initial behavior of the machine ( just to take that off the table ).
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