Development and flight test of an augmented thrust-only flight control system on an MD-11 transport airplane

Abstract An emergency flight control system using only engine AFSthrust, called Propulsion-Controlled Aircraft (PCA), has AGLbeen developed and flight tested on an MD- 11 airplane.In this thrust-only control system, pilot flightpath and c.g.track commands and aircraft feedback parameters areused to control the throttles. The PCA system was LSASinstalled on the MD-ll airplane using softwareEPRmodifications to existing computers. Flight test resultsshow that the PCA system can be used to fly to an FADECairport and safely land a transport airplane with an FCCinoperative flight control system. In up-and-awayoperation, the PCA system served as an acceptable FCPautopilot capable of extended flight over a range of FDSspeeds and altitudes. The PCA approaches, go-arounds, FPAand three landings without the use of any normal flightcontrols have been demonstrated, including instrument GWlanding system-coupled hands-off landings. The PCA HDGoperation was used to recover from an upset condition.In addition, PCA was tested at altitude with all three IAShydraulic systems turned off. This paper reviews the ILSprinciples of throttles-only flight control; describes theMD- 11 airplane and systems; and discusses PCA system MCDUdevelopment, operation, flight testing, and pilot NDcomments. PCAPFDTRK"Chief, Propulsion Branch. Associate Fellow AIAA V/StAerospace Engineer"_PCAProgram ManagerCopyright © 1996 by the American Institute of Aeronautics andAstronautics. Inc. No copyright is asserted in the United States underTitle 17,U.S. Code. The U.S. Government has aroyalty-freelicensetoexercise all rights under the copyright claimed herein forGovernmental purposes. All other rights are reserved by the copyrightowner.