Patent ID: 7945425

Claim:
A method for detecting wing flap freewheeling skew failures in an aircraft having trailing edge (TE) flaps and associated flap drive mechanisms located symmetrically with respect to a sagittal plane of the aircraft, the method comprising: measuring the outputs of flap skew sensors of each flap drive mechanism of each flap of the aircraft when the aircraft is in flight (IF) and the flaps are extended to a selected position; computing the respective differences between the IF outputs of symmetrical pairs of the flap skew sensors; measuring the outputs of the flap skew sensors of each flap drive mechanism of each flap of the aircraft when the aircraft is next disposed on the ground (OG) and the flaps are extended to the selected position; computing the respective differences between the OG outputs of the symmetrical pairs of flap skew sensors; computing the respective differences between the computed IF output difference and the computed OG output difference of each symmetrical pair of the sensors; and, comparing the computed IF and OG difference of each symmetrical pair of the sensors with each of a predetermined maximum threshold value (MaxTV) and a predetermined minimum threshold value (MinTV) to determine whether a freewheeling skew failure exists in any of the flaps of the aircraft.