What was found
AFTER FLAPS WERE SELECTED UP, HYD PRESS ANNUNCIATOR REMAINED ILLUMINATED. AFTER 40 SECONDS -STAB MISCOMP- ANNUNCIATOR ALSO ILLUMINATED WITH FLASHING MASTER CAUTION. RAN AIRCRAFT ON EITHER & BOTH ENGINES CYCLED FLAPS FOUND STABS OPERATION WITHIN TIME LIMITS. (22 SECONDS FULL TRAVEL). CONNECTED GROUND HYDRAULIC UNIT. FOUND OPERATION STILL WITHIN LIMITS. (NO CHANGE) SUSPECT AIRSPEED SWITCH. (TAH32256). C/W AIRSPEED SWITCH CHECK, RESISTANCE BETWEEN PIN A AND B NOT TO BE INFINITE. REMOVED & REPLACED AIR SPEED SWITCH IAW 560 XL MM 27-40-00. C/W LEAK TEST IAW 560 XL MM 34-11-08, MM 604. POSITION HORIZONTAL STAB IAW 560XL MM 27-40-00. SYSTEM OPS TEST OKAY.