McCarran’s runways make Midway-like accident unlikely

Thursday, Dec. 15, 2005 | 7:45 a.m.

When Southwest Airlines Flight 1248 slid off the end of a runway during a snowstorm at Chicago's Midway Airport last week, the fatal accident set off a flurry of safety questions nationwide.

What caused the accident, which killed a 6-year-old boy? What can be done to prevent a similar occurrence from happening again? Could a similar accident happen at my home airport?

In Las Vegas, where Southwest is McCarran International Airport's busiest carrier, officials say a similar incident is unlikely.

Clark County Aviation Director Randy Walker said most of the factors involved in the Midway incident couldn't happen at McCarran.

While the accident at Midway, which occurred at about 7:15 p.m. Dec. 8, is still under investigation by the National Transportation Safety Board, details about how it occurred are starting to emerge.

Several factors are under investigation. The Boeing 737 with 98 passengers aboard landed in a heavy snowstorm with a slight tail wind on a 6,500-foot runway. Midway, which has about 300 departures a day and was built in 1923 during the propeller-airplane era, doesn't have 1,000-foot safety buffer zones at the ends of its runways as required by federal regulations adopted 20 years ago.

NTSB investigators interviewed the pilots, who said there was a slight delay in the deployment of the plane's reverse thrusters when they tried to slow the aircraft after the landing gear hit the runway.

Those combined factors resulted in the plane sliding through a fence and onto a busy street where the plane's wing crushed a car, killing the child. The accident injured 13 other people.

Of McCarran's four runways, the two shortest are just under 10,000 feet long, more than 3,000 feet longer than Midway's runway. McCarran's longest runway -- and the one used for most of the airport's landings -- is more than twice as long as the Midway runway, at 14,500 feet.

Walker also points out that one of the critical factors in the Midway crash -- the snowstorm -- wouldn't happen in Southern Nevada.

"I went to a conference once and was asked what we use to remove snow at McCarran, and I said, 'The sun,' " Walker said. "It's something that really affects operations at airports on the East Coast and in the Midwest, but we really don't have to worry about that here."

Walker said even heavy rain doesn't result in slippery runway surfaces because the runways are crowned and scored so that water drains quickly.

As for buffer zones at the runways' ends, six out of eight have 1,000 feet or more of open space as mandated by the Federal Aviation Administration. Parallel north-south runways have buffer zones providing space between the ends of the runways and Tropicana Avenue on the north and Sunset Road on the south.

The ends of the 14,500-foot east-west runway -- lengthened in the 1990s to accommodate jumbo jets coming from overseas destinations -- have less than 1,000-foot buffers near Eastern Avenue on the east and Las Vegas Boulevard South on the west. Walker estimated the buffers' lengths at the ends of the longest runway at 600 feet.

Walker said because that surface is so long, runway overruns aren't likely to happen and a landing aircraft would have plenty of room to slow down.

The other east-west runway has more than 1,000 feet at both ends.

Tony Molinaro, an FAA spokesman in Chicago, said the Midway accident has increased focus on the need for an Engineered Materials Arresting System -- known in aviation jargon as EMAS -- at airports that don't have the 1,000-foot safety areas at the ends of their runways.

EMAS is a type of crushable concrete that breaks when an aircraft rolls over it, slowing planes that overrun, overshoot or veer off runway surfaces.

Walker said because of the length of McCarran's longest runway, EMAS isn't essential to airport safety.

Jim Carr, vice president of flight operations at Las Vegas-based Allegiant Air, agreed with Walker. He said most aircraft must be required to come to a stop within 60 percent of the runway's total length and that the aircraft's weight figures into the equation when considering safe landings and margins of safety on aborted take-offs.

"Nobody would be operating here if safety wasn't a top consideration," he said.

The east-west runways handle three-quarters of the landings at McCarran.

The direction an airliner lands is determined by weather conditions. Normally, planes land into the wind, which helps slow them down on approach.

Walker said southwesterly winds are the norm at McCarran, so most planes land from the east.

Jeff Jacquart, airport program administrator at McCarran, said in 2004, 73 percent of the 500 to 525 daily landings of planes with more than 50 seats were from the east. That year, 2 percent of the landings were from the west, 13 percent were from the south and 11 percent were from the north. Because of rounding, the numbers for the four directions add up to 99 percent.

Molinaro said the FAA is conducting a nationwide inventory of airport runways to determine where EMAS is needed, and will finish the study by the end of the year.

EMAS is in place at the ends of 18 runways at 14 airports with installations under way at four more airports. The technology has prevented injury to passengers and damage to aircraft three times at New York's John F. Kennedy International Airport since May 1999.

Richard N. Velotta can be reached at 259-4061 or at velotta@ lasvegassun.com.