What was found
AT FL380 EICAS MAIN CARGO DOOR ILLUMINATED FOLLOWED QRH PROCEDURES & LANDED. LIGHT EXTINGUISHED PASSING 16,000 IN DECENT. NO CABIN DEPRESSURIZATION OR NOISE FROM CARGO DOOR. ON BOARDING ACFT FOUND BOTH DOOR LATCHED AND DOOR LOCKED INDICATIONS SHOWING GREEN LOCKED & LATCHED ILLIUMINATED. OPENED CARGO DOOR AND FOUND NO OBVIOUS DEFECTS TO LATCHING & LOCKING SYSTEM. CLOSED DOOR WITH BOTH LATCHED & LOCKED INDICATIONS SHOWING NORMAL & DOOR WITNESSED PHYSICALLY LOCKED. FOUND SWITCH S891 OUT OF TOLERANCE. ADJUSTED SWITCH IAW AMM 31-70-05-05- 99. AND AMM 52-71-09-2. OK FOR SERVICE.