Flight Data Recorder (FDR): Mandatory Parameters, Event Marks, and Use
The FDR records technical flight parameters to assist in accident analysis and troubleshooting. It is typically housed in a crash-survivable container (shockproof, fireproof, orange colored) fitted with an Underwater Locating Device (ULD).
Recording Requirement
The type and number of parameters recorded are determined by:
- Recording Capacity of the system.
- Applicable Operational Requirements (Regulations).
Mandatory Parameters
Common parameters include (but are not limited to):
- Time / Relative Time Count.
- Pressure Altitude and Airspeed.
- Attitude (Pitch and Roll).
- Heading.
- Normal Acceleration (Vertical G).
- Thrust/Power on each engine and Lever positions.
- Configuration (Flaps, Slats, Spoilers, Gear).
- Autopilot/Flight Director modes.
Operation
- Automatic Activation:
- Start: Prior to the airplane being capable of moving under its own power (often on engine start or power-up).
- Stop: After the airplane is incapable of moving under its own power (engine shutdown).
- Event Button: A button in the cockpit that allows the crew to place a Time Mark in the data stream. This highlights a specific event (e.g., a temporary system failure or turbulence) to aid investigators in locating the relevant data later.