BLACK BOXES        

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Context

• China’s aviation authority announced that a flight recorder, commonly known as “black box”, “from China Eastern MU5735 was found.

What are Black boxes?

• These are two large metallic boxes containing recorders that are required to be kept on most aircraft, one in the front and the other in the rear.
• The recorders record the information about a flight, and help reconstruct the events leading to an aircraft accident.
• Black boxes are a blazing, high-visibility orange in colour, so that crews looking for them at a crash site have the best chance of finding them.

Types

• The cockpit voice recorder (CVR) records radio transmissions and other sounds in the cockpit, such as conversations between the pilots, and engine noises.
• The flight data recorder (FDR) records more than 80 different types of information such as altitude, airspeed, flight heading, vertical acceleration, pitch, roll, autopilot status, etc.
• Black boxes are mandatory on commercial flights. Their purpose on aircraft is not to establish legal liability, but to identify the causes of a mishap and, therefore, help to prevent adverse incidents in the future.

History

• The use of black boxes dates back to the early 1950s, when, following plane crashes, investigators were unable to arrive at a conclusive cause for the accidents.
• An Australian scientist named David Warren is often credited with their invention.

Technicalities

• In the initial days of the black box, a limited amount of data was recorded on wire or foil. Thereafter magnetic tape was used, and modern models contain solid state memory chips.
• The recording devices, each weighing about 4.5 kg, are stored inside a unit that is generally made out of strong substances such as steel or titanium.
• They are insulated from extreme heat, cold or wetness. The FDR is located towards the tail end of the aircraft because that is usually where the impact of a crash is the least.
• To make black boxes discoverable under water, they are equipped with a beacon that sends out ultrasound signals for 30 days.

https://indianexpress.com/article/explained/everyday-explainers/explained-china-plane-crash-black-box-7833767/

https://www.reuters.com/world/china/chinese-search-second-black-box-crashed-jet-2022-03-24/