EMER DECLARED.

Narrative

DURING CRUISE; ENGINEER INFORMED US OF A SLOW HYD LEAK IN THE A SYS. RATE OF LEAK WAS VERY SLOW; BUT QUANTITY FINALLY DROPPED BELOW A REASONABLE LEVEL FOR SIMPLE COLD SOAKING. CAPT DECIDED TO MONITOR QUANTITY A BIT LONGER FOR HIMSELF AND IMMEDIATELY CHKED FIELD CONDITIONS AT DEST IN CASE A SYS FAILED COMPLETELY. QUANTITY CONTINUED SLOW DROP AND CAPT DIRECTED HYD LEAK OR LOSS CHKLIST. INITIAL ITEMS WERE ACCOMPLISHED; AND FLUID STOPPED DROPPING. AS MORE THAN 1 GALLON STILL REMAINED; AND RWY WAS IN GOOD SHAPE AT PLANNED DEST; CAPT ELECTED TO CONTINUE THERE. THE REMAINDER OF CHKLIST WAS REVIEWED IN CASE THE SYS FAILED DURING ATTEMPT TO REPRESSURIZE FOR LNDG. CAPT DECIDED TO SET UP A LONG PATTERN IN ANTICIPATION OF POSSIBLE FAILURE; BUT ELECTED TO TRY USING NORMAL HYDS FIRST; AS RATE OF LEAK WOULD NOT DEPLETE SYS UNTIL WELL AFTER LNDG. TO ENSURE TFC PRIORITY; FIRE/RESCUE COVERAGE AND ACCESS FOR A TUG TO RWY AREA; CAPT ELECTED TO DECLARE EMER. THANKS TO EARLY DEPRESSURIZATION; FLUID LEVEL REMAINED ADEQUATE; AND LNDG WAS MADE WITH MOST HYD SYS RECOVERED PER CHKLIST. POSTFLT REVEALED LEAK WAS IN MAIN FLAP MOTOR.