AD FAA-2010-0221

We are adopting a new airworthiness directive (AD) for certain Model 777-200, -200LR, -300, -300ER, and 777F series airplanes. This AD requires installing new operational program software for the autopilot flight director computers. This AD results from reports of rejected takeoffs at speeds above takeoff decision speed following inadvertent autopilot engagement on the ground, and from the discovery during flight simulations that the climb gradient is less than optimal for obstacle clearance during a performance-limited takeoff situation. We are issuing this AD to prevent inadvertent engagement of the autopilot during takeoff roll, which could result in rejected takeoff at rotation speed, and consequent possible overrun of the runway. We are also issuing this AD to prevent a lower-than-optimal climb gradient during takeoff, and consequent failure to clear obstacles on the ground during a performance-limited takeoff.