Wingman: Available Technologies Might Have Saved Comair 5191

Wingman believes several technologies, already available and in use, might have prevented the Comair accident at Lexington, and should be more broadly considered as a way to reduce accidents in the taxi, takeoff and landing phases of flight.

On August 27^th a Canadair CRJ200ER operating as Delta Connection Comair 5191, crashed on takeoff from Lexington Kentucky's Blue Grass Airport.  Forty-seven passengers and two crewmembers were killed, including the captain.  The first officer, who was operating the aircraft during the takeoff, survived.

By all accounts the pilots attempted to takeoff on Lexington's Runway 26, which is 3,500 feet long, rather than Runway 22, for which the flight was cleared.  It was still dark (pre-dawn) and there may have been light drizzle as the aircraft taxied out.  Runway 22 is Lexington's main runway and is 7003 feet long.  Tragically, however, the pilot's took off on Runway 26, which is only 3500' in length - apparently not long enough for a CRJ200 with its weight that morning.

The U.S. National Transportation Safety Board is of course investigating and the world will have to wait for its official results.  But as frequently happens following accidents whose cause seem so obvious - in this case human error - calls for changes begin to emerge.  Most of these, up to now, have dealt with tower staffing issues and the status of the airport's configuration, particularly Runway 26.

Wingman suggests we take a larger view, especially how new technologies that are now available, or are emerging might have at some point prevented this accident from happening.

Some of these technologies that are becoming more commonly adopted: One, Honeywell's RAAS (runway awareness and advisory system), may be the most applicable to this accident.  Others, such as enhanced vision would have given the crew an image of the runway that could have indicated their mistake, and some synthetic vision systems might also have been very helpful if the right cues would have been displayed.

RAAS

If the Comair aircraft had been equipped with Honeywell's RAAS, an automated female voice would have announced, "Approaching 26," as the aircraft approached the first following its starting point.  If, following that alert, the mistake continued, when the captain lined up, the female voice would have announced, "On Runway 26," which of course was the wrong runway.

But even if the crew had missed or ignored these advisories, RAAS would have announced when reaching the first 100 feet of the 3,500-foot runway:  "3,400 remaining," and would have continued to call out the distance if the takeoff continued, according to Tommy Littlejohn, Honeywell Aerospace's director of flight operations.

In other words, at some early point, when the aircraft was still in a relatively low energy state, the pilots might have become aware of their error, and could have avoided their terrible "catch-22" choice of proceeding to an under speed takeoff, or attempting an extremely dangerous high-speed abort off the runway end.

EVS and/or SVS

One can assume that if the pilot's could see the entire runway environment as they taxied, they wouldn't have turned onto, lined up with, and continued their takeoff on a runway that was obviously too short.  Several of today's EVS (enhanced vision systems) can give pilots that ability - especially when the only obscuration is darkness.  And if one or both pilots had the added advantage of seeing the outside world through a head-up display, the mistake would have been even more apparent, immediate and compelling.

EVS of course is a powerful aid when visibility is obscured by weather phenomena too, and is especially useful when combined with a modern head-up guidance system that gives pilots very precise guidance during approach, landing and takeoff where a large percentage of accidents still occur.

SVS (synthetic vision systems), too, would have given the pilots strong visual indications that they were on the wrong runway, and has many of the same positive attributes of EVS, which again is especially useful when combined with precise flight guidance.

GPS-Based Surface Guidance

Other surface guidance systems that use GPS and geographical databases to accurately depict the aircraft's position on the airport surface in real time (so-called moving maps) are also obviously relevant to avoiding accidents such as this.

ADS-B and ASDE

Broadcast automatic dependent surveillance (ADS-B), by itself, and ASDE (airport surface detection equipment), including its improved variations such as ASDE-X can also be very useful, but are indirect, in that they are showing someone else (a ground controller or another pilot) the error, and would rely on the information being quickly passed on to the crew.

History of Accidents On or Around Airports

The Lexington accident represents the deadliest case in the U.S. of a plane taking off on an unintended runway, and fortunately this kind of accident has been relatively rare.  In fact, aviation accidents of all types have been decreasing for years.

Overall the accident rate worldwide for commercial aviation has been falling fairly dramatically especially during the period between 1950 and 1970, largely due to the introduction of new technology during this period.  This includes more reliable jet aircraft and their modern systems and a greatly improved radar-based air traffic control.  Added to that have been a myriad of other technological advancements ranging from artificial horizons, weather radar and VOR and ILS navigation in the middle of the last century, to autopilots and flight directors, to today's commonly used flight management systems and better situational displays, as well as safety-specific technologies such as TAWS (terrain awareness and warning system) and TCAS (traffic alert and collision avoidance system).

Still, we have a few accidents such as this one at Lexington, and too many of these occur on or near the ground.

According to Boeing's most recent "Statistical Summary of Commercial Jet Airplane Accidents," which covers worldwide operations between 1959 and 2005, over two-thirds (69%) of serious accidents (hull loss and/or fatalities), occurred during takeoff, initial climb, and on final approach and landing.  Of these, 12% occurred on takeoff and 52% on final approach and landing, where these technologies are most pertinent. 

Technology isn't the only answer of course.  Attention to human factors while designing and certifying equipment, and developing procedures and training, have been, and will continue to be, crucial in safety improvements.  Appropriate regulatory oversight is also necessary.

In addition, economic choices are a fact of life too, and even safety improvements must be subjected to cost versus benefit analysis. But fortunately, as technology matures, its cost usually comes down.  Honeywell's RAAS reportedly now costs about $18,000, and is likely less for bulk purchases.

Technology is important but shouldn't be used to take human beings out of the loop.  Rather, technology should enhance aircraft operations by providing additional information which allows humans to make better choices and avoid senseless errors.

Regarding the Lexington accident, one columnist wrote: "[T]he crash is a grim reminder that high-tech equipment still requires human oversight…. Maybe we all rely too much on technology to do our work and keep us safe... Everything was working properly, on board and in the tower, except the people."

This observation misses the mark.  This accident was obviously a human error, but it wasn't because of an over reliance on technology.  Wingman believes this tragedy should cause us to continue to use our human ingenuity to develop technology to overcome our natural predilection to sometime make mistakes.  09-06-2006.

Click here to become a registered Flt Tech Online subscriber and receive headlines delivered to your e-mail each week

Click here to go back to the headlines