What was found
INSPECTION OF FLEET ACFT SN IN THE BC AND BD RANGE HAVE REVEALED CRACKING OF THE MAIN WING SPAR WEB IN CARRY THROUGH OPENINGS AND END CAP SUPPORTS. IN THE WHEEL WELL AREA, THERE ARE 2 OPENINGS IN THE WING SPAR WEB FOR FUEL AND HYD LINE PASSAGE. ONE OPENING IS A RECTANGLE APPROX 3" X 6" AND THE OTHER OPENING IS A CIRCULAR HOLE APPROX 1.5" IN DIAMETER. INSP OF THESE AREAS HAVE REVEALED CRACKS EMANATING FROM THE CORNER RADIUS OF THE RECTANGULAR OPENING AND CRACKS EMANATING FOR THE CIRCULAR HOLE. MANY OF THE CRACKS TERMINATE AT AN ADJACENT RIVET HOLE. AS MANY AS 4 CRACKS IAW OPENING HAVE BEEN FOUND, BUT TYPICALLY ONLY 1 OR 2 ARE FOUND. THE OEM REPAIR FOR CRACKS IN THE SPAR WEB OPENINGS HAS BEEN TO BLEND OUT THE CRACKED AREA OR STOP DRILL IT, AND ADD A DOUBLER OVER THE ENTIRE AREA (APPROX 1 SQUARE FOOT). 17 ACFT HAVE BEEN FOUND TO HAVE CRACKS IN THESE AREAS. ADDITIONAL CRACKS HAVE BEEN FOUND IN THE SPAR END CAP SUPPORT, (PN 101-120025-83 LT) AND (101-120025 RT). THE END CAP SUPPORT PROVIDES A STRUCTURAL ATTACHMENT POINT FOR THE LANDING GEAR ACTUATOR FITTING TO THE SPAR. THE CRACKS IN THE SPAR END CAP SUPPORT HAVE PRIMARILY BEEN IN THE LT AND RT VERTICAL CORNERS OF WHERE THE SUPPORT ATTACHES TO THE SPAR. THE CRACKS VARY IN LENGTH FROM .2500" TO 3" LONG. INSP OF THESE AREAS REQUIRES USE OF A BRIGHT LIGHT AND MIRROR. THE OEM HAS NOT APPROVED A REPAIR OF THE SUPPORT AND IT REQUIRES REPLACEMENT IF FOUND CRACKED. 12 ACFT HAVE BEEN FOUND TO HAVE CRACKED SUPPORTS, EITHER ON THE LT OR RT SIDE.