This article provides a list of aircraft accidents and incidents for which flight data recorders (FDRs) and cockpit voice recorders (CVRs) were not recovered or were destroyed or otherwise failed to provide complete and correct information.
FDRs and CVRs in commercial aircraft continuously record information and can provide key evidence in determining the causes of an aircraft loss.
The greatest depth from which a flight recorder has been recovered is 16,000 feet (4,900 m), for the CVR of South African Airways Flight 295.
Most flight recorders are equipped with underwater locator beacons to assist searchers in recovering them from offshore crash sites, however these beacons run off a battery and eventually stop transmitting.
Some recorders have also failed to provide adequate information for various other reasons, such as poor maintenance, disconnection from their source of power, or having relevant information erased by the recording of later events.