What was found
SAT - FLIGHT 998, THE CREW REPORTED AN ACRID SMOKE IN THE REAR OF THE AIRCRAFT WITH LAV SMOKE ALARM WHEN SWITCHING FROM APU TO ENGINE BLEEDS. MAINTENANCE INSPECTED THE AIRCRAFT, PERFORMED OPERATIONAL CHECKS OF THE ENGINE/APU BLEED SYSTEMS WITH NO DEFECTS NOTED, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.