What was found
DURING CLIMB, AIRCRAFT YAWED NOTICEABLY AND WAS ACCOMPANIED BY AN IE27 YAW FAILURE CAUTION LIGHT. RESET BOTH AP1 AND AP2 SWITCHES AND CAUTION LIGHT EXTINGUISHED. COLLECTIVE YAW CIRCUIT BREAKER WAS THEN FOUND TO BE TRIPPED. RESET CIRCUIT BREAKER. DURING DESCENT, A VERTICAL SPEED WAS ESTABLISED AT 400 FPM. AIRCRAFT THEN NOSED OVER AND REACHED A RATE OF 1100 FPM BEFORE PILOT DECOUPLED AP AND HAND FLEW AIRCRAFT TO LANDING. NOSE OVER WAS ACCOMPANIED BY AN IE40 ERROR. REPLACED NR 1 PITCH LINEAR ACTUATOR.