The Technology of Black Boxes

The worst case scenario for anyone on a flight is to have something go wrong that leads to a crash or fatal accident. Oftentimes, when there are no survivors left, the only source of explanation for investigators is what each aircraft is equipped with, a black box. 

Black boxes, or flight recorders, are electronic recording devices the size of a shoe box placed in the tail of every aircraft, where they are most likely to survive a crash. Composed of two devices to record the history of the flight, black boxes contain a flight data recorder (FDR) as well as a cockpit voice recorder (CVR). The FDR has a recording storage of 25 hours and keeps information regarding parameters such as airspeed, altitude, vertical acceleration, outside temperature, engine performance, fuel flow, flap position, and many more. On the other hand, the CVR, with only 2 hours of recording storage, is responsible for storing the crew’s interactions with each other, with air traffic control, and background noise that may be useful in determining the nature of the crash. 

In the case where a crash has occurred, locating the black box is crucial. Despite their name, black boxes are actually painted bright orange with strips of reflective tape to make them easier for investigators to track it down beneath all the debris and rubble from the plane. For the possibility of the plane crashing into a body of water, black boxes are equipped with an underwater locator beacon (ULB) which sends out an ultrasonic pulse detectable by sonar and audio equipment but inaudible to human ears. These pulses can transmit sounds from as deep as 4,200 metres and ping once every second for a battery life of 30 days. 

Designed to survive a plane crash, black boxes can withstand impacts of up to 750 km/h, maximum temperatures of 1,100 degrees Celsius for one hour, and a static load of 2.25 tons for at least five minutes. 

The most important part of the black box is the information within it that has been captured. Through a process that can take weeks or months to complete, investigators attempt to recreate the events of the accident to the best of their abilities. The recordings and data are extracted in a lab, and then played back for a team of experts to interpret. From this, causes of the incident or accident are addressed and the sources of errors reduced. 

Black box technology continues to advance as the National Transportation Safety Board (NTSB) is looking at the idea of implementing video recording capabilities. Black boxes remain a necessity, increasing the safety of the millions of passengers flying across the world each day.