NEW YORK — Investigators trying to figure out why AirAsia Flight 8501 crashed into the Java Sea on Dec. 28 might now have the tools they need to provide answers.
On Monday, the flight’s data recorder was pulled up from the bottom of the shallow sea. The cockpit voice recorder was retrieved early Tuesday after it was freed from beneath a wing’s heavy ruins. It could take up to two weeks to analyze all the data on the so-called black boxes. Based on past crashes, the information could be vital.
The two separate devices — actually orange boxes designed to survive extreme heat and pressure — should provide investigators with a second-by-second timeline of the plane’s flight.
The voice recorder takes audio feeds from four microphones within the cockpit and records all the conversations between the pilots and air traffic controllers, as well as any noises heard in the cockpit. That could be alarms going off or loud explosions. It records on a two-hour loop, so investigators here won’t just capture the plane’s final minutes but the entire 42-minute trip.
The flight data recorder captures 25 hours of information on the position and condition of almost every major part in a plane.
Some of the major items recorded include altitude, airspeed, the rate the plane climbed or descended, the compass direction it was flying, the angle up or down it was pointed, if the plane was leaning to the left or the right, the thrust of the engines, the rate at which fuel was flowing, the pressure in the hydraulic lines and the position of the flaps, rudder and landing gear.
While it could take up to two weeks to analyze all the data, investigators shouldn’t have any problems reading it. The boxes are designed to withstand a 2,012-degree fire lasting 30 minutes, then a 500-degree fire lasting 10 hours, as well as pressure from sea depths of up to 20,000 feet.
In past crashes, the flight data and cockpit data recorders have provided key information for investigators. When Asiana Airlines Flight 214 landed short of the runway in San Francisco in 2013, it was the data recorder that showed that pilots had let the plane fall well below its normal landing speed and that they realized this mistake only seconds before touching down.
