What was found
MEX - FLT 1111 - EN ROUTE DFW-MEX, DURING DESCENT FIRE DETECTOR LOOP LIGHT ON ANNUNCIATOR PANEL FLASHED ON AND OFF, ALSO MASTER CAUTION LIGHT FLASHING. LOOP LIGHTS ON OVERHEAD PANEL DID NOT ILLUMINATED. LANDED MEX WITHOUT INCIDENT. TIGHTENED CONNECTIONS AT LOOP DETECTORS ON BOTH ENGINES. RE-RACKED MASTER WARNING AND CAUTION CONTROLLER, RAN UP ENGINES AT DIFFERENT POWER SETTINGS UNABLE TO DUPLICATE, PERFORMED FIRE AND LOOP FUNCTIONAL TEST. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)