Final answer:
The Cockpit Voice Recorder (CVR) and Digital Flight Data Recorder (DFDR) automatically activate to record cockpit audio and flight data, respectively, when the aircraft's power systems are engaged, and continue recording through all flight phases, as well as after accidents to capture all pertinent data.
Step-by-step explanation:
CVR and DFDR Automatic Activation Logic
The Cockpit Voice Recorder (CVR) and Digital Flight Data Recorder (DFDR) are critical components of an aircraft's avionics system. They are responsible for recording the cockpit audio environment and the performance parameters of a flight, respectively. These devices are automatically activated based on specific logic designed to ensure that crucial data is captured for every flight, and more importantly, in the event of an incident or accident.
Airplane Power-Up and Flight Phases
The activation logic of both CVR and DFDR typically includes powering up when the aircraft electrical systems are energized. This can occur during the initial airplane power-up when the Auxiliary Power Unit (APU) is started, or when external power is applied. Once the aircraft engines are running, the recorders continue to operate throughout all the flight phases until the engines are shut down.
Automatic Activation During Flight
During flight, certain parameters such as the aircraft's airspeed, altitude, or engine power settings can be set to trigger recording. For DFDRs, they commence recording when the aircraft exceeds a predefined speed or when the aircraft lifts off the ground, indicating the start of the flight. Similarly, CVRs ensure all sounds within the cockpit are captured, starting before takeoff and continuing until the completion of the flight, through automatic engagement mechanisms.
Post-Accident Recording
Importantly, in the event of an incident or accident, the recorders are designed to continue recording for a specific duration, usually including a post-accident phase with protected memory, to ensure that all pertinent information around the time of the event is preserved.
In summary, the automatic activation logic of CVR and DFDR is an essential safety feature that ensures continuous recording of flight data and cockpit audio, which is vital for flight safety analysis and investigation purposes.