Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all the Airbus models identified above. This proposed AD would require modifying the electrical power supply logic for the integral lighting of the standby horizon indicator in the cockpit; accomplishing repetitive operational tests of the integral lighting logic system, and corrective action if necessary. This proposed AD is prompted by a report of temporary loss of six cathode ray tube flight displays and the integral lighting of the standby horizon indicator in the cockpit during takeoff, due to failure of the normal electrical power circuit. We are proposing this AD to prevent loss of that integral lighting due to such failure, which could result in inability of the pilot to read the backup attitude information during takeoff, and possible deviation from the intended flight path.