Flight Data Recorder – Cockpit Voice Recorder

Wg Cdr Rajagopal

Flight Data Recorder and Cockpit Voice Recorder

Index

Introduction to FDR

  • Flight data recorder preserves aircraft data for accident investigation
  • Trend analysis and trouble shooting is also done using data from FDR
  • FDR records data for 10 to 25 hours of flight data and kept in Black box
  • Black box is painted red or orange and is located in tail fin
  • The container is resistant to fire, heat, shock and water damage
  • Tail fin location reduces damage due to G forces in an accident

Components of FDR

  • Flight data recorder is mandatory for all aircrafts with all up weight of 5700 Kg
  • The FDR consists of four main components
    • Recording system
    • Control unit on the overhead panel
    • Control unit on the pedestal
    • Data Interface and Acquisition Unit
  • Data from DIAU is sent to the ‘Aeroplane Condition Monitoring System’
  • ‘Aircraft Integrated Data System’ can read this data for trend analysis
  • ‘Airborne Communication and Reporting System’ transmits data to ground

Control Panel of FDR

  • Overhead control panel controls two systems
    • Cockpit voice recorder (CVR)
    • Flight Data Recorder
  • GND CTL switch can be selected to ON or AUTO
  • ON means that the CVR and the DFDR are energized
  • AUTO means that the CVR and the DFDR will be energized on two conditions
    • On the ground with one engine running
    • In flight either with engine running or stopped
  • EVENT button in centre pedestal marks an event for analysis

Introduction to Cockpit Voice Recorder

  • Cockpit voice recorder is designed to record cockpit voices for investigation
  • Automatically records the last 30 minutes of voice transmissions
  • CVR is co-located with FDR in the shock and heat proof Black Box
  • Black box has an underwater locating device transmitting ultrasonic pulses
  • CVR automatically switches itself on three conditions
    • AC power is applied to the aircraft
    • Engine is running
    • Aircraft is airborne

Recording Channels

  • CVR records five types of sounds
    • Radio transmissions
    • Sounds in the flight deck
    • Inter-phone system
    • Aircraft voice or audio signals
    • PA system communications
  • Press ERASE button for two seconds to erase recordings on ground
  • Possible only when engines are stopped with parking brakes on

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