In the event of Air crash, Flight’s CVR and FDR provide vital information for the Air crash investigators.
After finding the black boxes, investigators download the data from the recorders in the lab and attempt to recreate the flight path, and events of the accident.
This process can take weeks or months to complete. Black box manufacturers supply the readout systems and software needed to do a full analysis of the recorders’ stored data.
If the black boxes are not damaged, Lab technicians can retrieve data quickly by simply play back on the recorder by connecting it to a readout system. With solid-state recorders, investigators can extract stored data in a matter of minutes through USB or Ethernet ports.
Most often, the recorders from wreckage are dented, damaged or burned. In these cases, the memory boards are removed, cleaned up and have a new memory interface cable installed. Then the memory board is connected to a working recorder. This recorder has special software to facilitate the retrieval of data without the possibility of overwriting any of it.
The Flight Data Recorder and the Voice Data Recorder are built from similar components. Both include a power supply, a memory unit, electronic controller board, input devices, and a signal beacon.
Crash Survivable Memory Unit (CSMU) of the recorder is designed to retain 25 hours of digital flight information. The stored information is of very high quality because the unit’s state of the art electronics allow it to hold data in an uncompressed form.
Integrated Controller and Circuitry Board (ICB) contains the electronic circuitry that acts as switchboard for the incoming data.
Each recorder may be equipped with an Underwater Locator Beacon (ULB) to assist in identifying its location in the event of an overwater accident. The device, informally known as a “pinger,” is activated when the recorder is immersed in water. It transmits an acoustical signal on 37.5 KHz that can be detected with a special receiver.