Airworthiness Directives; Boeing Model 737-600, -700, -800, and -900 Series Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -800, and -900 series airplanes. This AD requires installing and testing an updated version of the operational program software of the flight control computers. This AD is prompted by a report of an airplane pitching up with rapidly decreasing indicated airspeed after the flightcrew set a new altitude into the autopilot. We are issuing this AD to prevent anomalous autopilot operation that produces a hazardous combination of airplane attitude and airspeed, which could result in loss of control of the airplane.