OAKLAND, Calif. - Think of it as a sophisticated equivalent to a runaway truck ramp on the freeway. Contractors completed San Francisco Airport's (SFO) federally-mandated Runway Safety Areas 2 years ago.
As Pence's and other success stories show, similarly equipped airports with these end-of-runway systems, made of soft concrete, save lives.
They safely, reliably and predictably crush under the weight of an aircraft, jumbo jet or single passenger plane. But, in doing so, they do not rip the plane apart.
SFO's two main runways are so long that they do not require the system. But the two shorter runways, bordered by Highway 101 on one end and the bay on the other needed the improvement.
They are also installed or being installed at forty other U.S. airports. At its deepest the barrier is just over two feet high.
"In a relatively compact 500 by 250 foot footprint, we were able to meet the Federal regulations and provide a very innovative way to bring aircraft safely to a stop," says Doug Yakel, SFO spokesman.
Planes that land too far down the runway, land too fast, hydroplane on wet or icy runways, lose their brakes or have to reject a takeoff roll because of some equipment failure, all of which have occurred at airports around the world, often with disastrous consequences.
"If you can bring the aircraft in safely intact there's a lot less hazards to it," says Mr. Yakel.
So how large of an airplane can this stop? At SFO, it has to stop the largest aircraft likely to use this runway and that would be a fully loaded 747 weighing more than 400 tons.
This would have to stop it without seriously damaging the aircraft. "This is an added dimension of safety to allow the aircraft landing gear to gently sink into it and bring it safely to a stop," Yakel concludes.
Even if an overrunning plan tears one of these arrestors up, the soft concrete blocks can be quickly replaced at a cost far below a damaged or destroyed airliner, to say nothing of the saving of lives and limbs.