TEMPO.CO, Jakarta - A safety bulletin was issued by Boeing in the wake of the Lion Air flight JT 610 crash last week, which reminds pilots how to handle erroneous data from a key sensor in the Boeing 737 MAX series.
The U.S. Federal Aviation Administration (FAA) initial investigation found that one of the “angle of attack” sensors on Lion Air’s brand-new Boeing 737 MAX jet had provided erroneous data.
According to Boeing.com, Angle of Attack (AOA) is an aerodynamic parameter that is key to understanding the limits of airplane performance. The rising interest in AOA in commercial aviation was driven by recent accidents and incidents that resulted in new flight crew training programs.
On Boeing models currently in production, AOA is used to drive stall warning (stick shaker), stall margin information on airspeed indicators, and the pitch limit indicator (PLI) on the primary attitude displays. AOA information is combined with other data and displayed as an integral part of flight deck displays.
A procedure exists for pilots to comply with if the data from the sensor is damaged or lost, however, it is not clear the time available for the ill-fated Lion Aircrew to respond to such immediate situation in a relatively low altitude of 5,000 feet (1,524 meters).
The National Transportation Safety Committee (KNKT) reported that the budget airline’s technician in Bali changed the plane’s AOA sensor one day prior to the accident when the Lion Air JT 610 experienced flight indicator issues in a flight from Bali to Jakarta.