ST. LOUIS, Sept. 25, 1996 -- In another demonstration of its rapid prototyping capabilities, McDonnell Douglas has successfully developed and flight tested a navigation software module that will help Harrier pilots land safely on carriers in low visibility conditions.
The new Self-Contained Approach (SCA) software assists the pilot by autonomously calculating and displaying all the data needed to approach and vertically land in a small area. Hosted on a commercial Power PC processor, the SCA module was successfully demonstrated in two Harrier flights in August, less than two months after the company's Phantom Works division started the project.
"The software module is designed to use the Harrier's existing navigation systems to precisely calculate position and velocity relative to a small landing site," explained Jeff Maxwell, SCA team leader in the Phantom Works. "With this data displayed on the HUD, a Harrier pilot can successfully approach and vertically land on small carriers at sea, even at night or in poor weather."
According to Jackie Jackson, the McDonnell Douglas test pilot on both demonstration flights, the challenge of landing a VSTOL (vertical and short takeoff and landing) aircraft like the Harrier on small carriers is that the aircraft must be stopped first then landed, not the other way around.
"Around a ship it is critical to control the speed at which you're approaching so you can avoid any last-second major corrections to get it back aboard," Jackson said. "This system is the first I've seen using existing equipment that provides the pilot with a user-friendly display of information he needs at a critical time."
Using algorithms provided by NASA, a three-person Phantom Works' team developed the SCA software module using commercially available tools, including high-order languages (C and C++) and automated code generation. According to Maxwell, the module was easily integrated with the open system architecture incorporated in the test Harrier as part of an ongoing common operational flight program demonstration. The commercial Power PC processor used in the aircraft's mission computer was provided by Computing Devices International (CDI).
"The commercial off-the-shelf approach we're using for software development in the Phantom Works is allowing us to develop and field new software in record times at minimal cost," Maxwell said. "This recent success with the SCA software is also further proof of the value of our open systems architecture approach to avionics development."
The SCA flight demonstrations took place at McDonnell Douglas facilities in St. Louis on August 15 and 19. A U.S. Marine Corps pilot joined test pilot Jackson in the two-seat TAV-8 aircraft on the second flight.
"The Marine Corps is interested in the capabilities of the SCA module primarily because of increased Harrier operations aboard small carriers," Maxwell said. "But the module also can be used to assist in making approaches and vertical landings at small austere landing sites in less than ideal conditions."
Additional flight testing of the SCA software is planned for next year.
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