What was found
(CAN) COULD NOT GET LANDING GEAR DOWN. ALTERNATE GEAR EXTENSION CARRIED OUT. MAINTENANCE CARRIED OUT GEAR FUNCTION CHECK. WHEN FOURTH RETRACTION WAS ALMOST COMPLETED, 60-AMP CIRCUIT BREAKER TRIPPED. UPON DISASSEMBLY OF HYDRAULIC POWER PACK MOTOR, IT WAS DISCOVERED THAT THE BRUSHES WERE WORN DOWN TO THE LEAD RIVET. THE COMMUTATOR HAD SIGNS OF ARCHING, AND THE BEARINGS WERE STARTING TO FEEL ROUGH. THIS MOTOR IS AN 'ON CONDITION' ITEM. ORIGINATOR SUGGESTS A SERVICE LIFE OF 1,200 CYCLES.