What was found
AFTER TAKEOFF AFTER GEAR RETRACTION, SAW A MOMENTARY MASTER CAUTION WITH FLT CONTROL ILLUMINATED. QUICKLY EXTINGUISHED AND NOTHING ILLUMINATED DURING RECALL. ACFT GROUNDED. RETURNED TO DEPARTURE. REPLACED THE "A" SYSTEM LOW PRESSURE WARNING SWITCH IAW MM 27-09-61. LEAK AND OPS CHECK GOOD. REPLACED THE "A" SYSTEM EDP, NR 1 ENG, IAW MM 29-11-11, LEAK AND OPS CHECK GOOD. CHECKED AND REPLACED THE "A" SYSTEM EDP CASE DRAIN FILTER IAW MM 29-11-51. LEAK CHECK GOOD, NO CONTAMINATION NOTED.