Angle-of-attack estimation for analysis of wind shear encounters

Recent studies of severe wind shear encounters involving wide-body airliners have been based on flight-path wind estimates, made by analyzing digital flight-data-recorder (DFDR) records and radar records. Such estimates require a time history of the aircraft angle of attack, a record that is not usually included in the DFDR measurement set. This paper describes a method for reconstructing angle of attack that utilizes available flight records and aircraft-specific information associated with an aerodynamic model of the lift coefficient. Results from two airliner incidents in which vane measurements of angle of attack were recorded show good agreement between measured and calculated time histories. This research has been performed in cooperation with the National Transportation Board to provide a better understanding of wind shear phenomena.