What was found
FLAPS 'LOCKED OUT' IN THE MID-POSITION WHILE MOVING FROM THE FULL DOWN TO UP POSITION. THE MALFUNCTION WAS DUE TO A HIGH RESISTANCE IN THE INTERNAL MICROSWITCHES OF THE FLAP DRIVE UNIT. THE AIRCRAFT MANUFACTURER IS AWARE OF THE PROBLEM. THE FLAP DRIVE UNIT WAS REPLACED BY AN IMPROVED VERSION. P/N C136066-45, S/N 1051 REMOVED. P/N C152550-1, S/N 1007 FITTED. FULL FUNCTIONAL CHECKS CHECK OUT, AIRCRAFT FLOWN. NO FURTHER REPORTED DEFECTS.