Enhanced Ground Proximity Warning System (EGPWS)

The two major causes of commercial-aviation fatalities - controlled flight into terrain (CFIT) and approach-and-landing accidents (ALAs) - accounted for 80 percent of fatalities in commercial transport aircraft accidents in the 1980s. But over the last two decades, flight safety has improved thanks to the introduction of Enhanced Ground Proximity Warning System (EGPWS) technology.


CFIT occurs when an airworthy aircraft under the control of the flight crew is flown unintentionally into terrain, obstacles or water, usually with no prior awareness by the crew. This type of accident can occur during most phases of flight, but CFIT is more common during the approach-and-landing phase.

The primary function of a terrain awareness and warning system such as Honeywell's EGPWS is to reduce CFIT. The system achieves this objective by accepting a variety of aircraft parameters as inputs, applying alerting algorithms, and providing the flight crew with aural alert messages and visual annunciations and displays in the event that the boundaries of any alerting envelope are exceeded.

The system essentially monitors the airplane's location and altitude, providing a map-type display of surrounding terrain and sounding an audible alert if the airplane approaches too close to terrain, a body of water or a tall structure.

The original GPWS concept relied on information from the air data system and radio altimeter. Enhanced systems use data from satellite systems and databases containing information on a digital elevation model (digital presentation of the terrain elevation features on a topographic map) and an aeronautical database.

As a result of EGPWS, the risk of controlled flight into terrain is now 50 times less in Western Europe and North America than it was in 1991, making this one of the biggest success stories in the history of aviation. Since the introduction of EGPWS in 1996, Honeywell has received reports of more than 30 incidents where the EGPWS gave an alert and provided pilots with timely awareness of terrain in flight situations.

Honeywell has delivered more than 30,000 systems.