The objective of this paper is to present an evaluating method for
irregular deviations of flight control surface deflected angles based on flight
data through the post flight analysis. The flight datasets are extracted from
quick access recorder (QAR) available in the Flight Operations Quality
Assurance (FOQA) program. The lift-to-drag (L/D) model for an aging
twin-jet transport will be established through the fuzzy-logic modeling
(FLM). The irregular deviations of flight control surfaces can be examined
by the L/D model-predicted results through sensitivity analysis. If the
irregular deviations of flight control surfaces are not rigged before the flight,
the flight control system may not work properly and it may have flight
safety concerns in flight. The present concept is an innovation to improve
the flight data analysis to monitor the irregular deviations of flight control
surface in the present program of FOQA and to increase operational
efficiency for the aircraft carriers.