What was found
(CAN) FROM TSB A01A0112, FOLLOWING TAKE OFF OF A FLOAT EQUIPPED DHC 3T, THE CONTROL COLUMN PITCHED VIOLENTLY FORWARD AND BACK BEFORE RETURNING TO A NEUTRAL POSITION. THE AIRCRAFT THEN PITCHED DOWN AND CONTACTED THE WATER IN A NOSE DOWN, WINGS LEVEL ATTITUDE. THE AIRCRAFT SUSTAINED SUBSTANTIAL DAMAGE AND SANK. THE OCCUPANTS ESCAPED WITHOUT SERIOUS INJURY. INVESTIGATION REVEALED THE CABLE-OPERATED JACKSCREW JAMMED DUE TO INTERNAL CORROSION OF THE JACKSCREW. ONCE JAMMED, THE RIVET SECURING THE FORK END TO THE ACTUATOR SHEARED RESULTING IN A FREE FLOATING HORIZONTAL STABILIZER.