Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 777-200 and -300 series airplanes. This proposed AD would require replacing the battery packs of the emergency power assist system (EPAS) of the left and right non-overwing exit doors with new or modified battery packs. This proposed AD is prompted by intermittent failures of the EPAS battery pack found during testing, which are due to switch contamination, cam alignment problems, and inadequate self-test capability. We are proposing this AD to prevent failure of the EPAS, which could result in the inability to open the exit door during an emergency evacuation.