NASA DEVELOPS NEW DIGITAL FLIGHT CONTROL SYSTEM

Barbara Selby
Headquarters, Washington, DC         December 12, 1994
(Phone:  202/358-1983)

Michael Mewhinney
Ames Research Center, Moffett Field, CA
(Phone:  415/604-9000)

RELEASE:  94-209

NASA DEVELOPS NEW DIGITAL FLIGHT CONTROL SYSTEM

     Landing a jet on a small ship in choppy seas at night is 
a tough job, even for experienced pilots.  NASA has 
developed and is now testing a new integrated flight and 
propulsion control system to help pilots land under these 
and other adverse conditions.

     Aerospace engineers at NASA's Ames Research Center, 
Moffett Field, CA, are developing the digital fly-by-wire 
flight control system to reduce a pilot's workload and help 
stabilize landing aircraft.  NASA is testing the new flight 
control system in the V/STOL (Vertical/Short Takeoff and 
Landing) Systems Research Aircraft (VSRA) to improve 
takeoff and landing capabilities for V/STOL aircraft in 
reduced visibility.  The VSRA is a modified version of the 
U.S. Marine Corps' AV-8B Harrier jet fighter, which can 
take off and land vertically.

     "Digital fly-by-wire can give the pilot direct control 
over the aircraft's velocity," said Ed Aiken, an Ames 
aerospace engineer.  "It helps the pilot control the 
aircraft at low speed," he said.  "At low speed in a V/STOL 
aircraft such as the AV-8 Harrier, you lose the stabilizing 
effects of the aircraft's aerodynamics and only the 
aircraft's propulsion system holds you aloft."

     The new automated flight control system features both 
heads-up and panel-mounted computer displays to help the 
pilot control the aircraft.  "Pilots can land with very low 
visibility, at night or in a hazardous landing zone," said 
program manager John Foster.  "They can slow the aircraft 
to hover and land vertically on a small site."

     The flight control system also automatically integrates 
control for the aircraft's thrust and thrust vector angle.  
"We can change the aircraft's thrust angle automatically to 
improve control during hovering," Foster said.  "This 
allows the pilot to concentrate on other tasks such as 
avoiding obstacles or communicating with the ship if 
landing at sea."

                     -more-

                      -2-

     Flight tests, which include simulated shipboard landings 
using the Global Positioning System for guidance, will 
continue at Ames through Dec. 31.  Project participants 
include pilots and engineers from the Marine Corps, 
McDonnell Douglas, Lockheed, Boeing, Northrop/Grumman and 
NASA.

     "This research provides some valid design guidelines for 
these aerospace companies to apply to a new STOVL (Short 
Takeoff and Vertical Landing) fighter," Aiken said.

     "They can study our test results and modify the flight 
control system for their particular aircraft," Foster said.  
"They want a control system they can build with minimal 
risk and investment.  We think ours will work.  It really 
does reduce the pilot's workload."

     The VSRA research project is supported by NASA, the U.S. 
Marine Corps and the U.S. Naval Air Systems Command.  
Flight research data will be used to develop and validate 
integrated control technology for future Advanced Short 
Takeoff and Vertical Landing (ASTOVL) aircraft.

                         -end-

NOTE TO EDITORS:  A photo and video are available to 
support this release.
Photo No.  B&W 94-H-415; Color 94-HC-376


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