What was found
SEATS WERE REMOVED, UNUPHOLSTERED, STRIPPED OF ORIGINAL PAINT FOR REPAINTING. UPON INSP OF LT AND RT FRONT SEATS BEFORE PRIMING AND REPAINTING, CRACKS APPROX. 270 TO 320 DEGREES AROUND WERE DETECTED FROM WELDS AT SUPT BRKTS CONNECTING UPPER TUBULARS OF SEAT FRAME. RT SEAT WOULD HAVE SEPARATED AT FRONT BRKTS CAUSING FRONT PASSENGER TO FLING BKWD WITHOUT NOTICE. LT SEAT HAD ONLY ONE CRACK, LT UNDETECTED MAY NOT HAVE CAUSED PILOT TO FLING BKWD BUT WOULD CAUSE PRESSURE ON OPPOSITE SEAT FRAME SUPPT BRKTS AND WOULD LEAD TO CRACKS. REPAIR/ GRIND OUT CRACKS AND WELD (TIG OR OXY/ACET GAS) BY AN AUTHORIZED INDIVIDUAL, OR REPLACEMENT OF SEAT FRAMES. THESE PARTICULAR CRACKS WERE WELDED AND 337'S PREPARED.