What was found
DURING ROUTINE BATTERY CHANGE, MECH NOTICED 3 OUT OF 4 MOUNTS ON A/C EVAPORATOR ASSY CRACKED. UNIT JUST INSPECTED 5 DAYS PRIOR WITH NO DEFECTS. UNIT LOCATED BETWEEN ENG EXHAUST EJECTORS. THESE AFT COWLING ARE NOT NORMALLY REMOVED BETWEEN ENG CHANGES OR MAJOR INSPECTIONS WITH EXCEPTION OF 1 COWLING REMOVED TO SERVICE BATTERY. IT IS KNOWN BY MFG THIS PROBLEM EXISTS. REF A.E.C. LETTER DATED MAY 2, 1995. AN INTERVAL TIME NEEDS TO BE ESTABLISHED SO UNIT CAN BE REPEATEDLY INSPECTED, 25 FLIGHT HRS SEEMS ADEQUATE. SB OR TECH BULLETIN NEEDS TO BE ISSUED. UNIT SITS ABOVE T/R DRIVE SHAFT & REQUIRES A CERTIFIED TECH TO EVACUATE FREON SYS & SERVICE UNIT ACCORDING TO FED REGULATIONS, A SERVICE NOT READILY AVAILABLE.