On 12 September 2015, an Airbus A320 autopilot and autothrust dropped out as it climbed out of Perth and multiple ECAM system messages were presented with intermittent differences in displayed airspeeds. During the subsequent turn back in Alternate Law, a stall warning was disregarded with no actual consequence. The Investigation attributed the problems to intermittently blocked pitot tubes but could not establish how this had occurred. It was also found that the priority for ECAM message display during the flight had been inappropriate and that the key procedure contained misleading information. These ECAM issues were subsequently addressed by the aircraft manufacturer.