Flight Data Recorder (FDR): Mandatory Parameters, Event Marks, and Use

022-14-02Pablo Asensio Martínez2026-03-271 min

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:

  1. Recording Capacity of the system.
  2. 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.