I have done a touchdown auto in a Squirrel without using the collective at all!
The rotten collective lock engaged while the lever was on the floor and I was manoeuvering for the touchdown. (This was a left-hand drive machine, throttle and other bits next to the left door, me sitting in right seat for dual check)
Flare, looking good, take pitch pull before sink... and there is no movement off the floor. Ground coming up faster and I am pulling hard up. Call to other pilot "The collective is jammed!"
Other pilot looks at collective lock, sees it engaged, tries to push lever down to disengage, but I am pulling upwards much harder.
I nosed over to keep some speed and level the skids, we touched down fast and bounced over a taxiway, just missed a ditch on the left, and finished in a cloud of dust and a hearty Hi-Ho Silver!
Throttle to idle, handed over to other pilot, got out, walked around aircraft to other side, opened door, undid collective lock, broke it off so it wouldn't happen again. No damage to aircraft at all - love those solid skids.
