The “black box” is a crucial component in forensic investigations following aviation disasters. This term actually refers to two robust devices—the cockpit voice recorder and the flight data recorder—both of which are typically bright orange rather than black. On Friday, federal investigators successfully retrieved the black boxes from the passenger aircraft that tragically went down in the Potomac River near Washington D.C. on Wednesday. This collision resulted in the loss of 67 lives, marking it as the deadliest aviation incident in the United States since 2001.
Black boxes serve a significant role in aiding investigators as they piece together the circumstances leading to air crashes. Their vibrant orange color is intended for visibility, ensuring they can be easily located amid wreckage, sometimes even at substantial ocean depths. They are usually positioned in the tail section of the aircraft, considered the most resilient part, according to the National Transportation Safety Board (NTSB). In addition, these devices are fitted with underwater beacons that activate when submerged, allowing them to transmit signals from depths of up to 14,000 feet (approximately 4,267 meters). Although the beacon’s battery lasts for around a month, there is no established data shelf life. Over the years, there have been successful recoveries of black boxes from submerged aircraft; for instance, the boxes from an Air France flight that went down in the Atlantic Ocean in 2009 were retrieved after being lost for two years at depths exceeding 10,000 feet, enabling technicians to salvage most of the data.
When black boxes are found submerged in saltwater, they are first kept in fresh water to eliminate the corrosive salt. If water has infiltrated the devices, they undergo a meticulous drying process that can last several hours or even days in a vacuum oven to prevent damage to sensitive memory chips. Technicians check the electronics and memory for any necessary repairs and thoroughly examine chips under a microscope.
The cockpit voice recorder captures essential audio, including pilot communications, engine sounds, and even radio transmissions, as outlined by the NTSB. Depending on the incident’s nature, investigators analyze these sounds, focusing on engine noise and warning signals, which can provide insights into engine performance and system malfunctions. The conversations between the flight crew and air traffic control are also recorded, and the meticulous transcription of this audio can take up to a week to complete.
On the other hand, the flight data recorder tracks significant flight parameters such as altitude, airspeed, and heading, monitoring at least 88 parameters as mandated for newly constructed aircraft. Some advanced models can even record more than 1,000 details, covering everything from flap positions to smoke detector statuses. The NTSB has stated that the data from these recorders can be used to generate a computer-animated flight reconstruction. According to past reports, a flight data recorder can store up to 25 hours of information, which might include data from previous flights that can often assist in identifying mechanical issues. Although preliminary data analysis can be completed within a day, full investigations may extend over several weeks.
The inception of black boxes can be attributed to at least two innovative individuals. French engineer François Hussenot developed a device in the 1930s that documented flight parameters on photographic film. Later, in the 1950s, Australian researcher David Warren invented the cockpit voice recorder after analyzing the crash of the first commercial jetliner, the Comet, in 1953. Warren’s experience was deeply personal, as he lost his father in a 1934 plane crash. He created a working prototype in 1956, but it took time before aviation authorities recognized its importance for investigation purposes, leading to wider adoption in commercial aviation.
The moniker “black box” has various theories attached to it. Some suggest it originates from Hussenot’s film-based system, which operated within a light-tight box. Others speculate it might become black after being exposed to intense heat during accidents. However, the Smithsonian Magazine states that the name simply emerged within the post-World War II era of electronics, where it came to refer to any device whose input and output were more critical than its internal workings. The media continues to utilize the term largely due to the sense of intrigue it carries, especially in the aftermath of aviation disasters.
