EASA 2020-0181

Requires amendment of the applicable Airplane Flight Manual to incorporate applicable emergency procedures cases of display failure. The AD is prompted by occurrences of primary display unit (PDU) data flickering on affected aircraft equipped with EASy software. Investigations have not identified the precise root cause, but have highlighted this phenomenon is linked to a modular avionics unit (MAUxA) failure, which leads to primary flight data flickering on the MAUxA PDU (blinking red crosses and/or blinking blue screen background). This situation inhibits the use of the MAUxA PDU and may have disturbing side effects on the other PDU. This condition, if not corrected, could lead to excessive workload, preventing the crew to perform communication and navigation tasks. To address this potential unsafe condition, Dassault issued an emergency procedure “ALL DU BLANK” dedicated to the event of an unrecoverable failure of all display units and an abnormal procedure “Intermittent loss of ADI and HSI data on PDU” dedicated to recovering the flickering of one PDU and the related side effects.