TO THE APU DOOR. SERVICE LETTER I4-APR-2003 SI. 737-SL-49-072 131-98 APU START SYSTEM IMPREOVEMENT - INTRODUCTION OF NEW START CONVERTER UNIT AND START POWER INFORMATIONAL UNIT. SERVICE LETTER 73-JUL-2001 MOS MOS - (s) INFORMATIONAL SL 737-SL-49-074 PAINT PEELING OFF FROM APU EDUCTOR INLET DUCT. S