What was found
BOS - USED ALTERNATE GEAR EXTENSION - ON APPROACH THE LANDING GEAR FAILED TO EXTEND WITH THE GEAR SELECTOR IN THE DOWN POSITION, (NO GEAR OR DOOR MOTION SENSED). THE CREW USED ALTERNATE EXTENSION AND GEAR EXTENDED. AN UNEVENTFUL LANDING WAS MADE. IN BOS MX PERFORMED CHECKS PER THE TSM, NO FAULTS WERE NOTED ON LGCIU NR 1/2 BITE CHECKS. NO INDICATIONS OF ANY PROBLEMS. PER AWA TECHNICAL SUPPORT THE FOLLOWING COMPONENTS WERE REPLACED, AND ALL FUNCTIONAL CHECKS WERE GOOD. LANDING GEAR CONTROL LEVER - P/N: 210TS07Y01, S/N: 1470, TT: 10356 - TC: 3950. LGCIU DOWTY ELEC CONMT LTD - P/N: 6647005004D, S/N: 2243, TT:8110 - TC:3376 - TSR: 1530. LGCIU - DOWTY ELEC CONT LTD - P/N: 6647005004D - S/N: 2212 - LOC: NR 2 -