Originally Posted by
helispotter
I wonder whether it could have reasonably been detected during regular inspection but was somehow missed prior to both accident? Or could it have remained hidden until a sudden failure?
I flew the SH-2F, which also has the servo flap system. You can fly that bird with no hydraulic pressure - it's a 13,000 pound helicopter, roughly, at max gross weight.
I am not sure if the servo flap system between K Max and SH-2F is identical, but I suspect it is very similar. The amount of play in the tower rods (from the azimuth up to the rotor head area) and the amount of play at the end of the clevis where it was attached to the flap itself was an inspection item on each daily / turnaround.
I am not sure how the K-max is maintained, but I'd be surprised if those connection points weren't as closely watched as on the SH-2F.
Yes, that servo flap is a primary flight control.
Digging back into old memory here:
There was an infamous (among the H-2 community) accident IIRC the 1970s (might have been an SH-2D, but I think it was an F).
Something came loose among the upper transmission doors, in flight, and ended up taking out a servo flap on one of the blades.
Nobody walked away from that crash.
As I recall the brief from our safety officer almost 40 years ago, the blade more or less went divergent and impacted the body of the aircraft at flight RPM.
One of our preflight items was the security of a locking pin on the aft clamshell doors - we were taught (in the RAG) that it had been added to prevent the doors from opening in flight after that accident. (Another day, I can share with you why the bolts in the azimuth were added).
Sorry to see the K Max running into problems, it's a unique bird that has done a lot of hard work over the years.
At one point (back in the 90's) the US Navy was proposing to have it do VERTREP from Military Sealift Command ships, as a replacement for the CH-46. The difficulties in getting the night / IFR certification, and instrumentation, proved to be too big of a hurdle to overcome.
A comment on the lawsuit: I am skeptical of the 'design flaw' assertion. My suspicion is that it was more likely either (1) maintenance error or oversight as a root cause, or (2) a flaw in the fabrication of one of the parts that make up that assembly.
I fail to see how one could blame the pilot, though, if the servo flap fails and / or falls off.
The loss of that critical flight control surface would mean that the blade would be all over the place as it rotated, and it will end in tears rather quickly at that point.