Stopping Runaway Planes

When a cargo plane this summer overran the runway at John F. Kennedy International Airport, it didn't end up in Thurston Basin waterway. It came safely to a stop in a bed of crushable material at the end of the runway.

In laboratories at the University of Dayton Research Institute (UDRI), researchers are working with the Federal Aviation Administration (FAA) and Engineered Arresting Systems Corp. (ESCO) to test how this material performs under a variety of environmental conditions to determine its lifespan.

ESCO, which is based near Philadelphia, has installed arresting systems at the end of 10 commercial runways, is testing one at LaGuardia Airport and will install another at Hyannis Airport in Massachusetts this month.

It’s a significant research effort because the FAA now requires a 1,000-foot-long runway safety area at commercial airports, and not all airports can afford to extend their runways. On average, 10 airplanes overshoot runways each year, and more than 350 runways don’t meet FAA criteria, according to Ryan E. King, civil engineer at the FAA’s William J. Hughes Technical Center at the Atlantic City International Airport.

“There have been different generations of this technology, and I think we've arrived at one that works reliably and is practical,” said King, noting that the beds have stopped two planes at Burbank Airport in California. “With this research project, we’re studying strength and performance life cycle trends -- particularly how moisture affects the performance of the beds.”

ESCO, which designs and manufactures aircraft arresting systems for commercial and military aircraft, developed the material out of a lightweight, airy material called cellular concrete. The company patented the product as EMAS (Engineered Material Arresting System).

“It behaves much like if you’re riding a bicycle and hit a deep patch of sand,” said Richard Angley, project manager for ESCO. “It’s the interaction between the material and the aircraft’s tires that provides the drag to decelerate the plane. We prefer to be the product of choice in safely decelerating overrunning aircraft. That’s what we strive for in our quality and the way we do business. UDRI is helping us get a better understanding of the lifespan of an EMAS system because it is such a new technology.”

In the field, UDRI researchers are performing a feasibility study to determine if ground penetrating radar (GPR) – a technology traditionally used to find underground utilities -- can be used to measure moisture in the runway beds. The GPR system, which was manufactured by Geophysical Survey Systems Inc., has appeal due its ability to make non-intrusive measurements over a large area. In the lab, UDRI’s structure and component characterization group will be exposing the material to various temperatures and moistures to test its strength, while UDRI’S analytical support group will test the permeability and moisture contents of various coatings and EMAS samples.

“This stuff works really, really well at stopping airplanes.  It's still a fairly new technology, and we need to continue testing its performance under various environmental conditions,” said Michael Craft, an electrical engineer who’s performing the work under a $95,000 contract from the FAA and a $60,000 contract from ESCO. Both contracts are extensions of previous research tests UDRI has performed.

UDRI’s work in runway disaster prevention dates back to the late 1980s when research engineer Bob Cook, now retired, performed a series of computer simulations on a shock-absorbing “foam bed” made out of material similar to Styrofoam. He discovered the material could stop a Boeing 747 without harming passengers or seriously damaging the aircraft. In the early 1990s, he served as a consultant to the FAA when it conducted testing of the beds at its technical center at the Atlantic City International Airport.

In 2000, UDRI research engineer Geoffrey Frank measured the sound waves of jet blasts – research that helped ESCO develop more durable tops for the beds.

“If a plane overruns a runway, you hope it lands in a nice grassy field, but that’s not the case at all airports,” Craft said. “Sometimes there will be an ocean, homes, a big culvert or a railroad track.  This technology will be invisible to most people, yet we’re improving safety in a very visible way.”

EMAS was first installed at JFK International Airport in 1996. If that technology had been in place a dozen years earlier, researchers says it could have stopped SAS Flight 901. When the DC-10 overran the runway, it plunged into the drainage canal, injuring a dozen people and requiring $22 million of repairs to bring the aircraft back into service as a cargo plane.

October 30, 2003