As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEADING EDGE FLAP ASYM EICAS MESSAGE IN FLIGHT RETURN TO AFW, A/C HAD 2 AIR TURNBACKS TO AFW. REMOVED AND REPLACED O/B SLAT RVDT M548, ADJUSTED O/B SLAT RVDT M544 IAW 27-81-11-424-029. FOUND L/E SLAT SENSOR S285 BAD. REMOVED AND REPLACED AND ADJUSTED SENSOR S285 PER MM 27-88-01/27-88-02, OPS CHECK SLATS NORMAL. ITEM CLOSED.