Airworthiness Directives; The Boeing Company Airplanes

We are superseding an existing airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, and - 900 series airplanes. That AD currently requires installing and testing an updated version of the operational program software (OPS) of the flight control computers (FCCs). This new AD requires an inspection for part numbers of the operational program software of the flight control computers, and corrective actions if necessary. This AD was prompted by reports of undetected erroneous output from a single radio altimeter channel, which resulted in premature autothrottle retard during approach. We are issuing this AD to detect and correct an unsafe condition associated with erroneous output from a radio altimeter channel, which could result in premature autothrottle landing flare retard and the loss of automatic speed control, and consequent loss of control of the airplane.