A flight data recorder, commonly known as a black box, is a mandatory component in every aircraft. It records all vital flight information using a specific algorithm. This recorded flight data can be accessed by authorities when necessary. Despite the common misconception, black boxes are predominantly bright orange in color, not black. These black boxes are designed to withstand extreme situations, making them invaluable tools in the field of aviation research, particularly due to their voice recording capabilities.
There are two primary types of flight recording devices: the flight data recorder (FDR) and the cockpit voice recorder (CVR). The FDR captures and stores a vast amount of data, including numerous parameters collected multiple times per second, providing a detailed overview of the flight’s recent history. On the other hand, the CVR records the sounds within the cockpit, including pilot conversations. These two devices can be integrated into a single unit. Together, the FDR and CVR objectively document the aircraft’s flight history, proving invaluable in subsequent investigations and analysis.
International regulations, under the oversight of the International Civil Aviation Organization, mandate that both flight recorders must be engineered to withstand the extreme conditions expected in a severe aircraft accident. This requirement ensures that the recorders are designed and constructed to survive the immense forces and harsh environments that could be encountered during such an event. By meeting these stringent standards, the flight recorders are equipped to protect and preserve the crucial data they contain, enabling thorough analysis and investigation in the aftermath of an aviation incident.
Components of Aircraft Black Box
Flight recorders are typically designed and tested to withstand a high impact of around 3400 g and extreme temperatures exceeding 1,000 °C (1,830 °F), as mandated by EUROCAE ED-112 regulations. Since 1967, these recorders have been a mandatory requirement in commercial aircraft in the United States. Following the mysterious disappearance of Malaysia Airlines Flight 370 in 2014, there have been calls from experts for real-time data streaming to the ground, along with improvements to the battery life of underwater locator beacons. These proposed enhancements aim to enhance safety measures and facilitate quicker response and investigation in case of accidents. There are two main components of Aircraft Black box:
A flight data recorder (FDR)
A flight data recorder (FDR), also known as an accident data recorder (ADR), one of the aircraft black box components, is an electronic device that is utilized to capture and store the instructions transmitted to various electronic systems aboard an aircraft. The data recorded by the FDR is of significant importance as it serves as crucial evidence during accident and incident investigations.The exterior of the flight data recorder (FDR) is coated in bright orange paint, making it highly visible in wreckage.
This helps with locating the FDR after an accident. It is typically mounted in the tail section of an aircraft, as this location increases its chances of surviving a crash. Recovering the FDR is usually a top priority for investigators following an accident. Analyzing the recorded data from the FDR can often reveal important information about the causes or contributing factors of an incident. Modern flight data recorders (FDRs) receive data from flight-data acquisition units through specific frames. They capture important flight parameters, such as control and actuator positions, engine information, and time of day. Currently, US federal regulations mandate a minimum of 88 required parameters (compared to 29 prior to 2002). However, some FDR systems monitor even more variables.
Typically, each parameter is recorded multiple times per second by flight data recorders (FDRs). However, if the data starts to change rapidly, some FDRs can store bursts of data at a higher frequency. Most FDRs have the capacity to record about 17-25 hours of continuous data in a loop. As per regulations, it is necessary to perform an annual FDR verification check (readout) to ensure that all mandatory parameters are being recorded accurately.Modern flight data recorders (FDRs) are usually double wrapped in corrosion-resistant stainless steel or titanium, providing strong protection.
They also have high-temperature insulation inside. Additionally, FDRs are equipped with underwater locator beacons. These beacons emit ultrasonic signals, known as “pings,” to aid in detecting the FDR when it is submerged. The beacons can operate for up to 30 days and function at depths of up to 6,000 meters (20,000 feet).An underwater locator beacon (ULB), also known as an underwater acoustic beacon, is a device installed on aviation flight recorders like the cockpit voice recorder (CVR) and flight data recorder (FDR). ULBs may also be required to be directly attached to the aircraft fuselage. When immersed in water, ULBs are activated and emit a 10ms ultrasonic pulse once per second at a frequency of 37.5 kHz ± 1 kHz. Their purpose is to aid in locating and recovering the flight recorders in case of an accident or water submersion.
Cockpit voice recorder
The cockpit voice recorder (CVR) also is one of the main components of Aircraft Black box, is a flight recorder specifically designed to capture the audio environment within the aircraft’s cockpit. Its main purpose is to assist in the investigation of accidents and incidents. The CVR achieves this by recording signals from the microphones and earphones used by the pilots, as well as an area microphone located in the cockpit’s ceiling. By capturing these audio sources, the CVR provides valuable insight into the communication and sounds within the flight deck during critical phases of flight.According to the FAA TSO C123b, which is the applicable standard for Cockpit Voice Recorder (CVR) equipment, the CVR must meet certain requirements. If an aircraft is equipped with digital communications, the CVR is obligated to record those communications with air traffic control, unless they are recorded by another system.
One of the FAA’s requirements, implemented in 2008, is that the CVR must have a minimum recording duration of two hours.The initial Cockpit Voice Recorders (CVRs) utilized analog wire recording technology, which was later replaced by analog magnetic tape. Certain tape units featured two reels, with the tape automatically reversing when reaching each end. The pioneering CVR was the ARL Flight Memory Unit, created in 1957 by Australian inventor David Warren and instrument maker Tych Mirfield.In addition to the CVRs using two reels, there were also units that employed a single reel configuration. These units utilized a tape that was spliced into a continuous loop, similar to how tapes are used in an 8-track cartridge.
In the CVR units with continuous loop tape, the recorded audio information would be overwritten every 30 minutes as the tape circulated. However, if a CVR is recovered from water and its housing has been breached, retrieving sound from the magnetic tape can be challenging.Modern CVR designs use solid-state memory and digital recording techniques, making them highly resistant to shock, vibration, and moisture. These advancements ensure better reliability. Furthermore, with reduced power requirements, CVRs can now include a battery, allowing for continuous recording until flight termination, even in the event of aircraft electrical system failure. This enhanced functionality provides improved safety and data preservation capabilities.
