A two-year "free-flight" test programme is set to begin in Alaska and Hawaii during 1999, following US Government approval of the so-called Ha-laska free-flight demonstration project.
US vice-president Al Gore says that, beginning in 1999, the US Federal Aviation Administration (FAA) will conduct a two-year demonstration of "free-flight" elements in Alaska and Hawaii involving military, commercial-transport and general-aviation aircraft.
Funding for the $250 million free-flight field test has yet to be established, but the FAA expects to pay for the necessary aircraft equipment. About 2,000 aircraft in both states will be involved in the evaluation.
The two states were chosen because of their controlled environment and affordable fleet size.
The air-traffic-management system will allow pilots and airlines to set their own flight paths. Controllers would intervene only to prevent accidents.
Meanwhile, Gore has also announced that the US Department of Defense will release a version of its Global Digital Terrain Elevation Database for use in civil aviation as part of the Clinton Administration's effort to reduce the number of controlled-flight- into-terrain (CFIT) accidents. The data will be incorporated into AlliedSignal Aerospace's recently certificated Enhanced Ground Proximity Warning System (EGPWS).
Gore has dubbed the DoD's action "a major breakthrough" towards controlling CFIT. "Combined with advanced navigation systems, this will provide pilots with the tools that they need to reduce, and maybe even eliminate, these kinds of accidents in the future," he says.
Access to the US military-produced digital terrain elevation database, which was created for cruise-missile targeting, is critical to widespread use of EGPWS. The system provides a detailed moving map of the terrain in the vicinity of an aircraft. Using the global-positioning system, the aircraft's position can be correlated with the Pentagon's terrain data in real time, allowing the pilot to maintain proper altitude and terrain clearance. The usual GPWS offers a 15sec alert, while the enhanced version provides a 1min warning.
The EGPWS has been approved for use on American Airlines Boeing 757s, and it plans to retrofit its entire fleet of 635 aircraft by mid-1999. United is evaluating the EGPWS on 20 of its Airbus A320s. Alaska Airlines will install it on 25 Boeing 737-400s.
The US National Transportation Safety Board urges the FAA to establish the need for the EGPWS, and if found effective, require all transport-category aircraft to be equipped with it.
Source: Flight International
