What was found
INTERNAL GASKET, PN 2519216-17, WAS INSTALLED ON THE EXTERNAL SIDE OF THE LT PYLON FIREWALL. EXTERNAL GASKET, PN 2452012-1, SHOULD HAVE BEEN INSTALLED. DUE TO THIS INSTALLATION AND THE NATURAL DETERIORATION OF THESE GASKETS, SEVERE FIREWALL DAMAGE OCCURRED. SUBMITTER RECOMMENDS A TIME CHANGE FOR THE GASKETS AND PARTICULAR INSPECTION IN THIS AREA DURING ENGINE INSPECTIONS. AFTT: 5,190.8 HOURS. LANDINGS, 5,145.