Late 80's - this happened during an exercise at RAF Odiham on a RAF Chinnok Mk1 (CH47-C). Aft Droop Stop found on the floor just after reaching full RRPM.
After many hours of theorising and trying to confirm exactly which was the errant Blade - it was decided to take the Hand-Rails off a "Giraffe" (Hydraulic lift/work platform with 20-25 feet of steel stairs leading to a work platform) secure some planks to form a smooth sloope and grease them up. the new Ramp was placed with cushioning, to the mid -Tunnel position Left side.
Crews practised the timing of the moving blades so that a call could be made as the errant blade was AFT of the ac giving time for the brake to start holding after the blade passed over the tunnel.
After approx 8 (yes eight?) hours of Ground Running - and now with an audience of several hundred people released from the exercise - a group of 4 or 5 crew were compressed into the tiny cockpit to get as many hands onto the Brake Lever. The RRPM was slowed to "as slow as as possible..." before the well-timed shout went to put the Brake on as fast as possible......
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All went well!
and the Rotors stopped within 1.5 turns and the only damage I saw was the Aft Rotor's Lower Oil Tanks and Aft Crown Fairing were crushed and the Upper Anti-Coll Lamp was broken.
The errant Blade didn't touch the tunnel covers and no damage was done to any blades - the "Ramp" was not touched.
Hope this helps?
Last edited by Rigga; 18th Nov 2011 at 17:34.
Reason: do you need to ask?