What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: DURING THE APPROACH THE FLAPS STOPPED MOVING WITH THE LEFT FLAP AT ABOUT 20 AND RIGHT FLAP AT 15. NO WARNINGS AND CAUTIONS WERE PRESENT IN THE COCKPIT. AIRCRAFT COMMENCED A GO-AROUND AND LANDED SAFELY AT BOS. REMOVED AND REPLACED FLAP TRANSMITTER (AALA202508118950), PER AMM 27-58-01-400-801. ALSO, REPLACED FLAP POSITON INDICATOR (AALA202508110399), PER AMM 27-58-02-400-801 AND AMM 27-59-01-400-801. OPERATIONAL CHECK GOOD.