What was found
AIRCRAFT RETURNED TO PLATFORM AS A CONSEQUENCE OF LT AIR CONDITIONING PACK WAS OUT OF SERVICE. AT PLATFORM, BOTH AIR CONDITIONING SYSTEMS WERE CHECKED BEING CORRECT. DURING CHECK, LT ENGINE BLEED AIR OFF LIGHT TURNED ON, LIGHT WAS DEFERRED IAW MM 36-11-1. AT MEX, B757 FIM PROCEDURE AND TESTS WERE PERFORMED IAW FIM 36-10-22 AND MM 36-11-09, ALL CORRECT.