What was found
(CAN) DURING DESCENT, A FLAP DR WARN LIGHT ILLUMINATED. MAINT FND PRIMARY DR TQ TUBE CAME OFF INBD SIDE OF LT INBD NR 1 FLAP BALLSCREW ACTUATOR AND CAUSED TQ SENSOR TO COUPLE AND ILLUMINATE FLAP DR WARN LIGHT. INVEST REVEALED FLAP DR COUPLING MOVED OFF SPLINE BECAUSE IT WAS MIS- INSTALLED. LOCKING BOLT FND SECURELY INSTALLED THRU HOLE IN TQ TUBE COUPLING. HOLE IN BALLSCREW SPLINE DR NOT LINED UP. SUBMITTER NOTES , 1/2 LOCKING HOLE COULD BE SEEN, APPROX .50 INCH OF SPLINE VISIBLE. CORRECT INST-.1250 INCH TO .25 INCH SPLINE SEEN WHEN HOLES ALIGNED AND LOCKING BOLT INST. LUB CAN HIDE LOCKING HOLE. SUBMITTER HAS ISSUED A COMPANY ADVISORY.