Purpose of the event button for an FDR?
It is an indication (by the crew) that a certain “event” was noticed (by the crew) – or wished to be noted (again, by the crew) during the flight – If a crew does not signal having noticed an event, it might indicate that they did not notice anything – This consideration would be part of an investigation for an accident or incident – As an example – in TWA 800 FDR, there was no “event” recorded, indicating that the flight engineer did not notice any unusual facts some moments before the explosion – It is assumed that the crew became immediately incapacitated – It also may be another means to “synchronize” FDR and CVR recordings –
