C. Donald Bateman

A series of aircraft crashes as a result of controlled flight into terrain (CFIT) led Bateman to take the initiative in creating a solution to these accidents. CFIT is defined as "where a pilot has the aircraft under control but unknowingly flies into terrain" This type of accident typically takes place during poor visibility. Bateman felt it was within his capabilities to construct a system that would detect hazardous terrain in the aircraft's projected path.[11]

The Ground proximity warning system (GPWS) serves the purpose of alerting pilots if their aircraft is in danger of flying into hazardous terrain or the ground. As explained by its patent description, it does so by using a radar altimeter system to keep track of the aircraft’s height above ground and will sound an alarm if the altitude is unsafe:[12]

"In order to provide for the additional effectiveness of a ground proximity warning system during a landing approach, the waypoint signal of an Area Navigation System is used in combination with an altitude above-ground-signal to compute a minimum terrain altitude for each point along the aircraft's approach to the runway. The minimum altitude is compared with the aircraft's actual altitude and if it is below the minimum an alarm is activated."

While this technology improved flight safety tremendously, it was still imperfect. It had two problems:[13]

1. No Warning: The primary cause of CFIT occurrences with no GPWS warning is landing short. When the landing gear is down and landing flaps are deployed, the GPWS expects the airplane to land and therefore, issues no warning.
2. Late Warning or Improper Response: This was primarily caused by blind-spots within the terrain. A sudden change in altitude—a steep slope, for example—would receive a late warning and the pilot might be unable to avoid the obstacle. This problem was implicated in the Garuda Indonesia Flight 152 accident.

Bateman continued to head the development of the GPWS, developing it into the Enhanced Ground Proximity Warning Systems (EGPWS), a version that features digital terrain mapping techniques paired with three-dimensional GPS information, providing for “look-ahead” capability as well as advanced aural and visual warnings. These advancements allow for conflict predictability and improve the crew’s warning time by 20 seconds in some cases.

EGPWS also provides protection when the aircraft needs to land, keeping it from landing short or in an area without a runway. It adds an increasing terrain clearance envelope around the destination runway to prevent premature descent rates. The system’s database can predict a safe descent profile because it knows the exact runway location and elevation through database sourcing as well as latitude/longitude sensing.[13]