The crash of Comair Flight 5191 in the early morning darkness of August 27 has given pause to the entire aviation community. As investigators grapple with the question of how an experienced CRJ100 crew could blast down an unlit, 3,500-foot runway without looking at so much as their heading, safety experts are becoming convinced that technology might have broken the chain of events that led to the crash. If the pilots simply had a moving-map depiction of the airport, the outcome likely would have been far different, some say.
The Comair crash wasn’t the only runway-realted mishap in recent months. Runway incursions over the summer nearly wrecked the flawless accident record of major U.S. airlines since the crash of American Airlines Flight 587 in New York almost five years ago (the Comair accident involved a regional airliner, and so this commendable safety record continues). On July 23 a departing United Airlines Boeing 737 came within 300 feet of colliding with a Boeing 747 cargo plane on an intersecting runway at Chicago O’Hare International Airport. The incident was blamed on controller error.
Less than a week later, two regional airliners nearly collided at Los Angeles International Airport when an America West regional jet strayed onto an active runway into the path of a departing SkyWest Embraer EMB 120. A warning by the tower controller and the quick reaction by the SkyWest pilot averted disaster as the airplanes missed each other by an estimated 150 feet.
Both incidents were attributed to problems with the airport movement area safety system (AMASS) equipment at the airports on the days the near misses occurred. The incident at LAX, has prompted a review of operating procedures that could include a restriction on intersection departures. Both episodes should serve as wakeup calls to pilots and controllers that airport surface operations remain near the top of the list of safety dangers.
Technology Coming to Business Aviation
Business jet manufacturers have been exploring technologies that could help curb or even prevent incursions. Aviation Communication & Surveillance Systems (ACSS), the Phoenix company that makes TCAS, TAWS and automatic dependent surveillance-broadcast (ADS-B) avionics, has held discussions recently with at least two OEMs about bringing a version of the company’s developmental surface area movement management (SAMM) system to new airplanes. The concept as described would use ADS-B technology to give pilots aural and visual warnings of other aircraft on the ground. SAMM’s software would judge which targets pose a potential danger.
“From our discussions with the OEMs, their feeling is that the surface area movement management function for runway incursion and enhanced situational awareness on the ground is the first thing that they want to roll out,” said ACSS chief technologist Cyro Stone. “That is what they think their customers will want as far as ADS-B is concerned.”
The SAMM concept is an element of a product and software suite from ACSS called SafeRoute. FAA Administrator Marion Blakey touted SafeRoute at July’s Farnborough airshow not merely for its safety benefits but also for the efficiency gains it could provide. UPS, in conjunction with ACSS and Boeing, is adding a SafeRoute feature that would help UPS pilots merge at cruising altitudes before flying continuous descent approaches at fixed intervals “like beads on a string,” in the words of Capt. Karen Lee, director of flight operations for the cargo airline.
UPS anticipates that merging and spacing application will improve the efficiency of flight operations, saving the carrier $1 million in fuel each year. The elimination of low-altitude maneuvering associated with “drive and dive” approaches will reduce noise and emissions near the ground. And the procedure will reduce controller workload, leaving them to manage a predictable flow of traffic and intervene only when needed. The major benefit of the concept is that it will give UPS pilots a clear picture of other UPS airplanes on approach, allowing them to self-separate even at night or in the clouds.
UPS also plans to use SAMM at its Louisville, Ky. hub by adding the application to the Boeing Class-3 electronic flight bags it has ordered for its Boeing 757s and 767s. SAMM shows a map of the airport surface and other airplanes. The active runway turns yellow and then red as an airplane approaches. It can also alert pilots to other airplanes equipped with ADS-B avionics and some transponders. After the Comair crash, safety experts said concepts like SAMM might well have prevented the accident.
The FAA is currently considering ADS-B-related avionics mandates after formally launching its nationwide ADS-B program in May. The plan is to take advantage of mode-S transponders in airliners and other aircraft–including some corporate jets–since many of these already emit the “extended squitter” si*gnal bursts used in ADS-B. But because general mandatory equipage is still thought to be many years away, the full benefits of concepts like SAMM could be a long time in coming.
But as the airlines begin signing on for ADS-B-related equipment that is designed to improve efficiency and by extension save them money on fuel, voluntary equipage could start to become the norm, even for business jet operators who are less affected by fuel costs, Stone said.
“We had an engineer at one business aircraft OEM tell us that the first time the CEO asks why the delay and the pilots say, ‘Well, we were in a longer holding pattern because everybody else is doing merging and spacing and we’re not,’ he’s going to want to get that technology on the aircraft,” Stone recounted. “It’s going to take some time to reach that point, but I really think this engineer was dead-on in his assessment, but definitely SAMM will make its way to business aviation much sooner.”
Business jet crews flying ADS-B-equipped aircraft will be able to “see” only other ADS-B-equipped aircraft on the cockpit traffic displays. Equipped aircraft constantly broadcast their current position and altitude, category of aircraft, airspeed, identification and other data, such as whether the aircraft is turning, climbing or descending. The transmission is made over a dedicated radio datalink and is known as “ADS-B out.” This is the basic level of ADS-B functionality.
ADS-B is received by ATC and ADS-B-equipped aircraft within reception range, typically about 200 nm. Reception by aircraft of ADS-B data is known as “ADS-B in.” This is the classification for airplanes with SafeRoute avionics. The same way merging and spacing reduces controller workload in the terminal environment, concepts like SAMM could reduce the potential for errors on the ground, where–as recent incidents and the Comair crash have shown–the dangers remain as real as ever.