What was found
FLT JB7--AFTER FLT, L-2 DOOR SLIDE DEPLOYED BY CATERING. R & R L-2 DOOR SLIDE IAW AMM 25-65-01 & ASSIST ACTUATOR DIAPHRAGM REPLACED IAW AMM 52-42-53. FOUND THAT THE CATERING CREW & FLT CREW FOLLOWED PROPER DOOR OPENING PROCEDURES. DURING L2 DOOR OPENING CATERING NOTICED THE SLIDE CASING & A STRING AT LOWER AFT CORNER HANGING DOWN & STOPPED OPENING DOOR. CATERING ATTEMPTED TO FREE THE STRING THEN SLIDE UNRAVELED & INFLATED BETWEEN FUSELAGE & PARTIALLY OPENED DOOR. FOUND A MECHANICAL MALFUNCTION OF SLIDE, STRING HANGING DOWN BUSTLE BRACKET RELEASE PIN LANYARD WITH PIN TORN OFF. CATERING PULLING ON LANYARD RELEASED SLIDE CASING CAUSING DEPLOYMENT.