What was found
FLAPS WOULD NOT EXTEND ON APPROACH. NO WARNINGS AURAL OR VISUAL. FLAPS TAKE 10 SECONDS TO EXTEND WHEN ACTUATED WITH HANDLE. TESTED IAW AMM 27-51-00-05 AND OPERATIONAL CHECK GOOD. PERFORMED ADJUSTMENT AND TEST OF FLAP CONTROL IAW 27-51-00-05 PROCEDURE 3 ELECTRICAL RIGGING OF FLAP CONTROL POTENTIOMETER L/R FLAP POTENTIOMETERS. ADJUSTED POTENTIOMETERS WITHIN SPECS. ALL ELECTRICAL POTENTIOMETERS NOW WITH LIMITS. REMOVED AND REPLACED FLAP CONTROL VALVE IAW AMM 27-51-15-04 PN ON AND OFF HP1416100-5 SN ON 51540 OFF 1539. OPS CHECK AND LEAK CHECK GOOD.