Tanada wrote:In a normal flight the tail section 'feathers' meaning it fold upward 90 degrees to act as a giant air brake for the craft to control descent speed. Apparently the copilot hit the unlock switch by mistake earlier in the flight, after that all it takes is turbulence to move the tail out of line. That happened when the craft was at Mach 1.4, causing the tail to rip apart. It is only designed to withstand feathering at Mach 1.0 and below. Early rumors blamed the engine that was running somewhat rough due to testing a new fuel mixture. If the feathering was unlocked and the engine 'burped' that could have caused the turbulence that deployed the air brake action and tore the ship apart.
Thanks for the explanation.
Hm...... so... *some* pilot error, and maybe bad engineering with the unlock button firing whatever bolts are locking that feather tail in place.
Just one button, switch, or lever, whatever it was.
You'd think something so "do not touch" important would be a big crank you've got to ratchet up, with some tension, to make sure you really are sure.
Important buttons should have a cover over the switch and stick the mission-ending buttons somewhere off from the other buttons. I don't know the details of course, why would the feather tail be unlocked like that.
I heard it speculated there could have been some problem in flight that the pilot thought the feather tail deployed would help with, we don't know, but really that thing is only supposed to be lowered at the lower speed as you say (heck, why wasn't there a computer altimeter master locking it).