Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD requires repetitive inspections to detect cracks in the vertical beam webs of the body station (BS) 178 bulkhead, and corrective actions if necessary. This AD also requires a terminating modification for the repetitive inspections. This AD results from reports of numerous cracks in the vertical beam webs. We are issuing this AD to prevent fatigue cracks in certain vertical beam webs, which could result in loss of structural integrity of the BS 178 bulkhead, and consequently could impair the operation of the control cables for the elevators, speed brakes, and landing gear, or could cause the loss of cabin pressure.