Description

On 30 October 2014, an en route Airbus A320 (EC-KCU) being operated by Vueling on a scheduled domestic passenger flight from Barcelona to Seville as VLG 2226 and an en route Boeing 737-800 (EI-EKS) being operated by Ryanair on a scheduled international passenger flight from Shannon, Ireland to Malaga as RYR314Q came into close proximity in night VMC despite the issue of coordinated TCAS RAs. The minimum recorded separation was 1.4nm laterally when also only 100 feet vertically.

Investigation

After a significant delay in notification of the occurrence, an Investigation was carried out by the Spanish Civil Aircraft Accident and Incident Investigation Commission (CIAIAC). Due to the lack of timely notification, no flight recorder data was available. However, OFDM data from both aircraft operators and ATC radar recordings were available although the ATC system did not have either contemporaneous or archive access to Mode S downlink data. It was noted that the A320 involved was equipped with TCAS v 7.0 software and that the series of activations of it during the occurrence included one which had been modified by the latest software version (v7.1) because of evidence that, depending on the method of presentation, it could increase the chances of pilots taking action contrary to that annunciated.