11. Head admitted there must have been fatigue cracks in the steering column of Senna's car. 12. A fatigue crack had initiated in weld metal on the inner surface of the socket. 13. This is essentially a notch in the material which can be a potential source of fatigue cracks . 14. This led to a fatigue crack in an attachment screw and allowed the trim tab to flutter. 15. The order stems from reports of fatigue cracks on the aft pressure bulkhead of some Boeing 737-200 models. 16. The prototype was later cut up after suffering from fatigue cracks in the engine / propeller mounting structures. 17. Overpeening will cause excessive cold working of the surface of the workpiece, which can also cause fatigue cracks . 18. The Washington Post reported on Friday that investigators have discovered fatigue cracks in the 22-year-old plane's rear fuselage. 19. Records indicate that other incidents of fatigue cracks have occurred in similar engines since 1974, the safety board said. 20. After propagating through the weld metal during a large number of flights, the fatigue crack entered the socket's parent metal.
