Last Sunday (27), rescue teams found the second black box of the China Eastern Airlines Boeing 737-800 plane, which crashed in the last week. The equipment could help explain the accident, which killed 132 people and still has many open questions.
While traveling between the cities of Kunming and Guangzhou, in southwest China, the aircraft made a sudden dive while at cruising altitude, starting a dizzying drop of a few minutes, until it hit the ground at an angle close to 90 degrees — falling down.
Officials said the pilots did not respond to repeated calls from air traffic controllers and nearby planes during the rapid descent. Therefore, the answer may lie in the two black boxes already retrieved.
How the black box works
The invention of the black box is attributed to Australian scientist David Warren, during the 1950s. Despite the name, they are fluorescent orange, so they are easily recognizable amid the wreckage of planes.
Generally, aircraft have two black boxes, one for storing recordings of voice conversations inside the cockpit and the other for technical data of the final moments of the flight – such as altitude, air speed, direction and engine thrust. They can provide a clearer picture of what caused the accident, through a software simulation.
Data is recorded on chips and other formats, and can store from a few tens of minutes to several hours of information, depending on the model used. They are made of stainless steel or titanium, weigh about 4.5 kilograms, and are typically placed on the tail of the plane. They can withstand impacts 3,400 times the force of gravity and temperatures of over 1,000°C. Even so, some newer models have an ejection system during the fall, to avoid potential damage to the equipment during a collision with the ground.
The use of black boxes is mandatory on aircraft with more than six seats and serves to help understand the causes and prevent accidents. However, in the future, they may be replaced by more modern systems, which transmit the plane’s data in real time and via satellite.
Clarifying the crash with the Boeing 737-800
Despite part of the black boxes being “severely damaged”, Chinese experts hope to decipher the mystery of the crash of the plane, which completely disintegrated during the impact.
During the procedure, the protective material from the recorders is removed and the connections are carefully cleaned. Thus, the data can be downloaded and copied. Depending on the condition of the equipment, it may be necessary to send them to outsourced specialists.
The expectation is to try to respond as a plane that was at cruising speed and altitude – the safest point of a flight – plummeted from a high altitude and in such a short time, something considered abnormal in aviation, even in an emergency situation. Radio silence and a slight recovery in altitude in the final seconds of the crash could indicate that the pilots were busy trying to avoid the crash.
There is still no deadline for Chinese authorities to issue a report on the causes of the accident. But usually a preliminary document is made about a month after the accident. A complete analysis can take more than a year.
Normally, a plane crash with modern planes is motivated by a number of factors and circumstances. Suspicions range from technical failures in the plane’s tail stabilizers, problems with engines or human intervention (either by mistake or deliberate overthrow of the aircraft by the pilots themselves).