Some of our CVR data are missing: 92 airline accidents & incidents 2014–2024

In recent years there have been numerous accidents and incidents in which investigators could not retrieve pertinent cockpit voice recorder (CVR) data. As a result, the investigations were hindered and potentially valuable information was not passed on to the wider aviation community to prevent future accidents. Accident investigation agencies have repeatedly called for the introduction of long-duration CVRs to mitigate this problem. In 2021 the European Union introduced regulations requiring newly-manufactured aircraft weighing over 27,000 kg to be equipped with 25-hour CVRs, and in 2024 similar requirements were introduced in the United States. The aim of this paper is to draw attention to the extent of the “missing data” problem and gain a greater understanding of the reasons behind it. Building on previous studies (Cookson, 2019, 2023) the paper examines 92 safety events that occurred from 2014 to 2024. The events are coded according to: (1) CVR recording duration, (2) CVR information provided in the investigation report, and (3) the reason why data were not available. The study identifies 48 events in which the CVR was not promptly deactivated and/or there was a delay in notifying the investigating agency, and a smaller set of 12 events in which pertinent data were overwritten due to excessive flight time. The paper also highlights a worrying lack of standardization in the way in which CVR data are presented in accident and incident reports.