Honeywell has started demonstrating an optional software upgrade to its enhanced ground proximity warning system (EGPWS) that is intended to curb runway incursions and improve airport safety. Called the runway awareness and advisory system (RAAS), the software-only modification uses the EGPWS unit’s internal database of runways and GPS-derived position to increase pilot situational awareness during taxi, takeoff and landing.

Developed by Honeywell’s Flight Safety Avionics division in Redmond, Wash., the advisory system will be available to airline customers and operators of large business jets fitted with Mark V and VII EGPWS units late this summer at a price of $14,000 per airplane. Soon after, Honeywell plans to bring the capability to its Mark VI and VIII devices for small to midsize business jets, as well as turboprops.

RAAS is designed to fill a potentially wide gap in safety until the introduction of future ATC services and avionics that will provide datalink position of all aircraft and vehicles on the airport on cockpit and head-up displays. The Honeywell system does not keep track of other aircraft nor does it issue a warning if the pilot tries to take off from the wrong runway. Instead, RAAS provides clues to the pilot that something may be amiss.

Putting It to the Test
Taxiing in a Honeywell King Air on Paine Field in Everett, Wash., last month test pilot Markus Johnson put the new system through its paces, demonstrating how RAAS gives useful cues to the pilots without overburdening the crew with unnecessary callouts. When approaching a runway during taxi a female voice gives the runway number, as in, “Approaching Runway One-Six Left.” If the airplane turns onto the runway, RAAS will say to the pilot, “On Runway One-Six Left.” 

During takeoff RAAS remains silent unless it senses that insufficient runway is left, at which point it will begin calling out runway length remaining. If the airplane instead sits on the runway waiting for takeoff clearance for longer than 90 seconds, RAAS will advise the pilot of the elapsed time, a clue that it might be prudent to give the tower a call. The system also provides a warning if the airplane attempts to take off from a taxiway.

In the air, RAAS tells the crew which runway it thinks the airplane is about to land on. If it deems the runway is too short it provides a callout of total runway length. Buyers, said Johnson, can decide how they want to configure the system. During demonstration flights from Paine Field, the unit was set to replicate the performance of an airliner, providing the advisories for any runway shorter than 5,000 feet. 

RAAS uses GPS to determine the airplane’s location. An expanded and more accurate database of runways contains the boundaries that allow the system to issue aural advisories. In the future Honeywell plans to enhance and validate the database as quickly as practical, with more airports added as each RAAS software revision becomes available.

“For now, only longer runways are included in the database,” said Johnson. “Eventually we want to have all runways, regardless of length, added to RAAS.”

The RAAS concept, he said, originated with Honeywell chief engineer Don Bateman, the man most responsible for the development of GPWS and EGPWS. It was Bateman, he said, who recognized that EGPWS could be upgraded to provide simple advisories until more sophisticated runway-incursion warning devices begin to emerge later this decade.

Recent FAA and NTSB statistics suggest that runway incursions are averaging one a day and close calls one every 10 days. In October 2001, at Milan Linate Airport in Italy, 118 people lost their lives when an MD-80 and a Cessna Citation collided on the runway in fog. That accident has prompted the U.S. Department of Transportation to call for new technology and better training to reduce incursions.

Runway Incursions ‘A Significant Danger to the Flying Public’
Earlier this year, DOT Inspector General Kenneth Mead warned that the potential in the U.S. for accidents similar to the Milan Linate crash poses a significant danger to the flying public and called on the FAA to address the vulnerability. Mead cited a study showing there is one serious operational error every three days–caused either by controllers or pilots–in which an on-airport collision “is barely averted.”

For its part, the FAA has become far more proactive in trying to reduce incursions in the last couple of years, establishing a system to categorize incidents by severity of risk and providing better training to controllers. The effort appears to be yielding benefits. Operational errors last year were down to 1,061 from an all-time high of almost 1,200 in 2001. Despite the positive results, Mead said the number of incursions is still “far too high.”

Honeywell’s RAAS could be a simple and relatively inexpensive way to give pilots at least basic protection against catastrophe. One useful feature of the system, for instance, alerts the crew of runway length available if they pull onto a runway and face the wrong way, as has happened during low-visibility operations.

Such a device may also have prevented the October 2000 crash of a Singapore Airlines 747-400 at Chiang Kai-Shek International Airport in Taipei, Taiwan. At night and in bad weather the airplane tried to takeoff from a closed runway. The jetliner slammed into construction equipment parked midway down the runway, burst into flames and broke into three pieces, killing 82 of the 179 people on board. RAAS would not have been able to alert the pilots that the runway was closed or that vehicles were obscured by fog farther down, but it would have at least advised the crew, who were cleared to takeoff on Runway 5L, that they were actually on Runway 5R.