A Study of Simplified Methods for Longitudinal Control Decoupling

Using an inflight simulator, a simple longitudinal decoupling concept was compared with conventional airplane characteristics for the approach and landing tasks. The decoupling system allowed the pilot to command flight path angle changes with the stick with little or no accompanying speed change; likewise, speed changes with only small accompanying flight path changes could be made with throttle only. The unique feature of the concept is that it is an open loop (that is, non-feedback) control system. Results indicate that in calm air and up to moderate levels of turbulence the decoupling system provides a substantial reduction in pilot workload. The program was supported by NASA, Langley Research Center, under Grant NSG 1234.