Failure analysis on tread throw of the tire of B737-800 airplane

This paper provides an analysis of tread throw of B737-800 airplane tire. The plane experienced tire tread throw during takeoff. Laboratory observation shows that there exist numerous dense beach marks around one shoulder area of the tire. These beach marks shows that the repair exposed cords area around tire shoulder is the origin of tread separation of the incident tire. It is believed that the poor adhesion of the repair exposed cords area caused fatigue accumulative damage to develop into a tread separation. The structure form of the main landing gear of B737-800 airplane leads to unbalanced loadings on the double-tire (wheel) of the main landing gear, this gave a promotion to tread throw of the tire. For this reason, repair limits for damages at tire shoulder should be controlled more strictly for tires of B737-800 airplane. A large deep foreign object damage (FOD) cut found on the center tread rib is ruled out to be the cause of the tire tread throw according to the sequencing crack method called T-junction procedure in wreckage analysis. Tire FOD cut simulation test was carried out to confirm this viewpoint about FOD cut.