India Crash To Spur Runway Safety Systems
The Indian air crash that killed 158 people at the weekend when an airliner plunged into a ravine may speed up calls for airports to invest in technology to save lives when planes overshoot the runway.
The disaster came four months after a potentially fatal crash was averted when a runway spillover system developed by a unit of French firm Zodiac prevented a jet from careering down a similar slope at Charleston, West Virginia.
The "EMAS" arrestor system was introduced last decade and is credited with capturing six planes which overran the runway including a Boeing 747 at New York's Kennedy airport.
It works by forcing a plane to slow down as its wheels churn up blocks of crushable, lightweight concrete in a safety zone set back from the end of a normal runway.
The concept sounds as simple as emergency gravel lanes designed to halt runaway trucks on steep roads, but is adapted to the weight and speed of an onrushing jet.
It took time to develop because the material needed to be fragile enough to break and provide resistance in an emergency but -- unlike gravel -- robust enough to allow access to fire trucks or tolerate the occasional wrong turn of a taxiing jet.
Experts stress it is too early to speculate on what caused Saturday's Air India Express crash at Mangalore or whether the EMAS system alone could have prevented the Boeing 737-800 shooting off the end of a table-top runway.
Reports say the runway had a safety zone of 90 metres including a bed of sand, which failed to halt the jet.
Regulators require a minimum runway spillover area of 90 metres (295 feet) but they also recommend 240 metres (788 feet) internationally and 1,000 feet in the United States.
EMAS is designed to cut these distances, for example where space is limited by a steep drop-off, water or wetlands.
Pilot unions have been pressing for tougher regulations including wider use of such systems after an Air France Airbus overran and caught fire at Toronto in 2005.
In the Charleston incident in January, a PSA Airlines Bombardier regional jet was ensnared in a bed of crushable concrete after aborting its take-off.
CATALYST FOR CHANGE
Minor "runway excursions" are relatively frequent and few attract notice, but overshooting the runway makes up a high proportion of those accidents that do cost lives, experts say.
"Accidents are rare in relative terms, but when they do happen, most are on approach and landing," said Paul Hayes, safety director at UK-based aviation consultancy Ascend.
Planes can overshoot a runway after approaching too fast, too high or without the proper configuration for landing.
According to Honeywell, these types of incident as well as runway incursions cost the industry USD$1 billion a year, presenting one of its worst safety headaches.
The turning point came on February 28, 1984, when a Scandinavian Airlines DC-10 slid off the runway after landing at New York's Kennedy Airport and came to rest in a shallow creek.
It was a lucky escape for the 163 passengers who evacuated on rafts or by climbing over wings, with only 1 serious injury.
But the accident at one of the world's busiest airports sparked research into new surfaces to deal with runway overruns.
In the 1990s the US Federal Aviation Administration issued a blueprint for an Engineered Materials Arresting System (EMAS), based on modern materials that would break up and halt a plane.
Experts say the FAA rejected sand as too unpredictable.
So far the only solution approved for use by the FAA was developed by ERSCO, a Zodiac subsidiary based in New Jersey.
But 14 years after EMAS was introduced, surprisingly few systems have been installed and almost none outside the US.
Manufacturer ESCO says it has installed 48 systems in the United States and two each in mainland China and Madrid. Taipei will see the next EMAS outside the US fitted later this year.
"It has taken longer to start up steadily outside the United States, but there is some interest," said Kent Thompson, vice president of airport engineering and sales said.
The principal barrier appears to be cost. Some experts also blame bureaucratic prevarication over rules for safety margins.
"The typical EMAS costs $USD5 million going up to USD$10 million or USD$12 million depending on the space. But that is small compared to the value of saving lives and aircraft," Thompson said.
The US Transportation Research Board estimates there are 18 "runway excursions" a year. Most are overruns on landing. Others happen when a plane aborts take-off or lands too early.
Besides safely capturing a plane on the ground once it overshoots, engineers are looking for ways to spot the dangers of such events happening even before the pilot touches down.
A Honeywell Aerospace executive said it had made a system to break the chain of events leading up to an overrun, giving pilots time to abort the landing and go around for another try.
"It is less than USD$30,000 for an upgrade; it's an option for airlines to choose," Vice-President Carl Esposito said.