Summary
The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all McDonnell Douglas Model MD-10-10F and MD-10-30F airplanes, Model MD-11 and MD-11F airplanes, and Model 717-200 airplanes. The existing AD currently requires a revision to the Limitations section of the airplane flight manual (AFM) to prohibit use of the flight management system (FMS) profile (PROF) mode for descent and/or approach operations unless certain conditions are met. This proposed AD would require, for Model 717-200 airplanes, upgrading the versatile integrated avionics (VIA) digital computer with new system software, which would end the need for the AFM revision. This proposed AD results from a report of two violations of the selected flight control panel (FCP) altitude during FMS PROF descents. We are proposing this AD to prevent, under certain conditions during the FMS PROF descent, the uncommanded descent of an airplane below the selected level-off altitude, which could result in an unacceptable reduction in the separation between the airplane and nearby air traffic or terrain.