INERT GAS SYSTEM - AIR SEPARATION UNIT - INSPECTION OF TUBES AND CLAMP INSTALLATION. SERVICE BULLETIN RECOMMENDED MOS 12-APR-2012 SB 737-09-1119 APU - ELECTRONIC CONTROL UNIT. SERVICE BULLETIN 10-JUN-1999 MOS - (s) SB 737-09-1133 AIRBORNE AUXILIARY POWER- AUXILARY POWER UNIT AIR INLET - AUXILARY POWER UNIT FLAP AND V