The FAA issued an emergency directive requiring all operators of early model Boeing 737s to conduct initial and repetitive electromagnetic inspections for metal damage fatigue. This applies to over 175 aircraft worldwide, including several of the 737-300, 737-400, and 737-500 series models. The FAA announcement came after a Southwest Airlines’ 737 suffered a hull rupture mid-flight, resulting in a five-foot hole in the roof and forcing an emergency landing at a military base. Since the incident, Southwest Airlines has discovered five planes with small cracks which need immediate repair. Boeing has also announced plans for s service bulletin recommending lap-join inspections, which is the section where the fuselage skin meet.