What was found
DURING THE 100 HOUR COMPRESSION TEST, THE ENGINE STOPPED BETWEEN TWO POSITIONS OF APPROXIMATELY 60 DEGREES OF PROP ROTATION FROM HARD INTERNAL CONTACT, FURTHER INVESTIGATION REVELLED THAT THE LOCK BAR ON THE NR 4 ROD LINK PIN HAD FRACTURED AND ALLOWED THE ROD PIN TO BACK OUT OF THE MASTER ROD. THE LOCKED CONDITION WAS CAUSED BY THE ROD PIN CONTACTING THE COUNTER WEIGHT. FURTHER INVESTIGATION FOUND THE LOCK BAR FOR THE ROD LINK PINS ON CYLINDERS 6 AND 7 HAD ALSO FRACTURED WITH NO PIN MIGRATION NOTED. NO PROBABLE CAUSE, NOW.