What was found
LOSS OF HYD SYS -A- QTY, 20 PERCENT AT FL290, INDICATIONS NORMAL. WHEN LANDING, QTY JUMPED TO & STABILIZED AT 46% RF, CREW REPORTED NO ISSUE WITH FLT CONTROLS OR STEERING. FOUND NO LEAKS, FLT CREW HAD FLT CONTROL SWITCH GUARD UP, FLIPPED GUARD TO ON, NOTICED A SUBSTANTIAL LEAK FROM LT WHEEL WELL COMPENSATOR CARTRIDGE ON FLT CONTROLS HYD MODULE. LOOSENED MOUNT BOLTS ON FLT CONTROLS HYD MODULE. R & R COMPENSATOR CARTRIDGE IAW AMM 27-09-51, SERVICED HYD, NO LEAKS ON COMPENSATOR OR HYD CONTROL MODULE. DURING LEAK CHK OF COMPENSATOR, OPS FLAPS-SLATS HYD -B- QTY TRANSFERED TO HYD -A- WHEN FLAPS IN TRANSIT LEADING TO HYD -A- BEING OVERFILL BEYOND 106 CAUSING HYD FLUID TO COME FROM HYD DRAIN MAST, HYD -B- WENT DOWN & EXTENDED FLAPS-SLATS & SPEED BRAKES MULTIPLE TIMES, COULD NOT DUPLICATE FAULT. SERVICED BOTH A & B HYD RESERVOIRS TO OPTIMAL LEVELS, EXTENDED FLAPS-SLATS & SPEED BREAKS AGAIN, NO CHANGE.