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Monday, July 26, 1999:

FAA/Industry Team Announces First Practical Helicopter Precision Approach to a Hover

BUNNELL, Fla., USA ( Sikorsky Press Release ) - A team of FAA and industry partners today announced that they had jointly developed an autopilot landing system on a Sikorsky S-76 helicopter that performs the first practical rotorcraft precision approach to a hover.

Demonstrations are being conducted at Flagler County Airport in Bunnell Florida, through Aug. 6. The team has been working for the last 20 months to perfect the system, which relies on a Special Category 1 Differential Global Positioning System (SCAT1 DGPS) ground station to provide glideslope and localizer approach guidance to a heliport.

"For the first time, we will be able to provide helicopter service to heliports and oil rigs in virtually any weather," said Nick Lappos, Sikorsky's Assistant Chief Test Pilot. The system should have wide appeal to users who must provide reliable transportation to obstructed heliports. It is anticipated that certification will lead to approach minimums below 100 foot ceiling and 600 feet visibility with current technology autopilots, and potentially zero-zero minimums with the next generation.

The DGPS team consists of the leaders in helicopter industry. Sikorsky Aircraft provided the test helicopter and systems integration management, Universal Avionics providing their GLS-1250 Landing System and UNS-1D Flight Management System, and Honeywell providing modified versions of their SPZ-7600 autopilot and EDZ-705 Flight Instrument System. In previous trials, the team used a Honeywell Peloris DGPS ground station, and at the latest trials, Raytheon provided its SCAT-1 DGPS Ground Station.

Team members include the Program Manager Paul Erway of the FAA Vertical Programs Office in Washington, D.C., and Test Pilot Jim Arnold of the FAA Rotorcraft Directorate in Ft. Worth, Texas. "This DGPS system will let us evaluate a whole class of precision helicopter approaches," said Arnold, "We hope to take advantage of deceleration and advanced avionics to bring approach minimums down to the heliport." Arnold plans to fold in the lessons learned with this system into new Advisory Circular certification guidelines for helicopters.

The DGPS approach uses technologies provided by team members from NASA and the National Research Council of Canada, who have been monitoring the program from its inception. Test pilots and operational pilots from around the world will evaluate the system in the weeks ahead. Precise position and human factors data are being taken by the FAA to establish certification guidelines, and noise data is being gained to support urban heliport operations. This data will also be used in helicopter WAAS and LAAS efforts in the future.

The pilot can perform the approach three ways -- coupled autopilot, flight directed, or with a "raw data" presentation similar to an ILS. Approach angles up to 9 degrees can be used. The final approach fix is two miles from the heliport to reduce airspace and approach time. Ground speed and wind vector indications are provided below 40 knots and a map of the arrival is presented on the HSI, with the heliport as the final waypoint.

The DGPS approaches for the program were designed by team member Satellite Technologies, Inc., and are encoded in the normal navigation data base of the Flight Management System by selecting the DGPS approach from the arrival menu.

"Government/industry partnerships can quickly develop infrastructure by sharing their resources," Lappos said, " When our team first discussed the idea, we all realized that we had a common goal, and that each of us held some key piece of the solution. With little more than a handshake and a common vision, we made it happen. The leadership of the FAA Administrator and the National Rotorcraft Technology Council were critical to the success of this project."