What was found
WAS COMPLYING WITH THE CH 4, DOC MV INSPECTION, CALLS FOR A DETAILED INSPECTION OF BOTH ENGINE & APU FIRE EXTINGUISHER WIRING. THIS IS THE FIRST OCCURRENCE OF THIS TYPE OF INSPECTION ON THIS AIRCRAFT SINCE NEW. THE APU SQUIB WAS WIRED CORRECTLY BUT I DID FIND THAT BOTTLE PRESSURE SWITCH ELEC CONNECTOR WAS NOT ATTACHED AND WAS HANGING LOOSE. OF THE FOUR SQUIBS ON THE TWO ENG FIRE BOTTLES, FOUND 3 OF THEM WIRED BACKWARDS. THIS WOULD HAVE PREVENTED THOSE SQUIBS FROM FIRING IF A PILOT WOULD HAVE SELECTED THAT SQUIB IN THE EVENT OF AN ENGINE FIRE. WITH HOW THEY WERE WIRED (FROM THE FACTORY) THERE WAS ONLY ONE SHOT AVAILABLE FOR THE LT ENG, & NOTHING ON THE RT ENG. THERE HAVE BEEN NO INSPECTIONS OR MX ON THE WIRING OR EXTINGUISHING SYSTEM SINCE THE PLANE LEFT THE FACTORY NEW. AD 2007-11-17 ADDRESSES THIS ISSUE AND WAS SIGNED OFF AS COMPLIED WITH AT THE TEXTRON AVIATION INC. FACTORY WHEN THE PLANE WAS RELEASED NEW. MANDATORY SERVICE LETTER SL560XL-26-02 WAS EFFECTIVE AT THE TIME THE ACFT WAS RELEASED AS NEW. THE SL STATES THAT ACFT WITH S/N 6307 AND ON WOULD HAVE THE SL INCORPORATED AT PRODUCTION. ABLE TO VERIFY THAT ALL THE SQUIB WIRES ARE LABELLED CORRECTLY AND THAT THE LABELS ARE CLEARLY LEGIBLE.