Overview
The French Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) published an interim report on three incidents involving Airbus A320 and A321 aircraft operated by Aer Lingus and Transavia. All three incidents were linked to failures of the Digital Radio and Audio Integrated Management System (DRAIMS), causing unavailability of transponders, ACAS, and difficulties with or loss of radiocommunication and datalink. The report details two incidents with substantial information and one with limited details.
Incident on 20 September 2024: Aer Lingus A320 (EI-NSF)
An Aer Lingus Airbus A320-251N, registered EI-NSF, departed Dublin for Bordeaux-Mérignac at 06:24 UTC. In cruise at FL 330, the crew heard crackling in headsets. The RMP 1 screen alternated between normal and an amber VHF PAGE NOT AVAIL message, while RMP 2 alternated with a blank screen. ECAM alerts included NAV ATC/XPDR STBY, TCAS STBY, COM RMP 2 OFF, and COM RMP 1 FAULT. At 07:22, the aircraft disappeared from radar. The crew attempted to reset RMPs and select transponder code 7600 without success. Radio contact was lost; the cockpit fell silent as headsets failed. The crew followed the air-ground communication failure procedure, descending per the flight plan in VMC. Brest ACC initiated alert and distress phases, coordinating with military units. The aircraft was visible on Flightradar24. After several attempts, radio contact was re-established at 07:39 on 121.5 MHz with Mont-de-Marsan CDC. Later, a loss of separation occurred with flight EFW59L, with minimum separation of 3.2 NM horizontally and 175 ft vertically. The crew landed at Bordeaux without further incident. Maintenance tests showed no anomalies on the transponder or RMPs.
Incident on 13 January 2025: Transavia A321 (PH-YHA)
A Transavia Airbus A321-252NX, registered PH-YHA, departed Granada for Amsterdam at 19:24 UTC. In cruise at FL 340, ECAM alerts NAV LS TUNING DISAGREE and NAV ATC/XPDR STBY appeared, along with TCAS STBY memo. The STBY NAV function activated without crew input, and radio frequencies desynchronized. The aircraft disappeared from radar six times between 20:48 and 21:07, reappearing with random transponder codes (e.g., 2107, 1001). Mode C was lost intermittently, and the IDENT function activated without crew action. Audio function was lost on the co-pilot's side. The crew attempted to reset RMPs. At 21:07, when transferred to Brest ACC, the crew could not change frequency; their transmission was received on the previous frequency. The alert phase was activated by Bordeaux ACC at 20:57.
Incident on 29 April 2025: Transavia A321 (PH-YHC)
A Transavia Airbus A321-252NX, registered PH-YHC, experienced a similar DRAIMS failure around 10:30 UTC. The BEA interim report notes that the incident occurred but provides no further details at this stage.
Conclusion
The BEA interim report identifies DRAIMS failure as the common explanation for the transponder and communication issues across all three incidents. Investigations are ongoing.