Search teams have recovered the black box of the Lion Air passenger plane that crashed into the Java Sea earlier this week with 189 people on board, Indonesian authorities said Wednesday. The Boeing 737 Max 8 plane lost contact with air traffic controllers shortly after takeoff, and investigators are still trying to determine what caused the crash, a first for a 737 Max 8. The flight data recorder has been found, while search teams are still trying to locate the plane’s cockpit voice recorder, according to an Indonesian official cited by Reuters. The voice recorder could prove vital in determining what caused the crash, as it is believed to contain the final words of the pilots. A spokesman for the airline confirmed earlier that the plane on a previous flight had encountered problems with sensors used to calculate altitude.