I don't know if one of my colleagues can point to a specific study. We have had voice recorders for years in aviation and for over 10 or 12 years in maritime. Without those recorders—and I can think of a number of accidents—we would not have known what had happened, particularly when the crew did not survive the accident or sometimes they may have survived but there may be discrepancies in their testimony or they simply don't remember everything that happened. As a result of that, steps have been taken, procedures have been changed, training has been increased, and technology has been introduced, and these things have improved the safety of the system.
The fact of being recorded also has a way of influencing and shaping people's behaviour. If there is an issue, for example, with inappropriate use of electronic devices while operating, people may be less inclined to do that if they know they're being recorded. It's very important, and as I mentioned in French, we can't solve the problems and we can't identify the safety deficiencies if we don't know what they are. We don't always know what they are unless we can get a holistic view of the accident based on voice recordings, video, if it's available, digital recordings, as well as any witness testimony that we have had access to.