The plane involved in this week's deadly crash in Spain is a workhorse model that is used extensively by many carriers around the world.
Officials at those carriers say the McDonnell Douglas MD-80 series _ which includes the Spanair MD-82 that crashed earlier this week _ is one of the safest planes around. They point out that the cause of the Spanair crash, which killed 153 people shortly after takeoff in Madrid, was still unknown on Friday.
The National Transportation Safety Board sent a team to Spain to help with the investigation because the plane was made in the United States. But determining the cause of the crash will be up to Spanish authorities, Laura Brown, a spokeswoman for the Federal Aviation Administration, said Friday.
The FAA doesn't rank the safety of plane types, but Brown added, "If we didn't consider an aircraft safe, we wouldn't allow it to operate in the U.S."
According to the Flight Safety Foundation, MD-80s have been involved in 15 fatal crashes resulting in 1,163 deaths since their first flight in 1979. The last MD-80 series aircraft was built in 1999.
Some crashes were blamed on pilot error, poor maintenance, runway incursions or other factors not strictly related to the aircraft's design.
A 1999 crash in Little Rock, Arkansas, that killed 12 was blamed partly on crew fatigue and error. Last September, 90 people died when an MD-82 landing in heavy rain in Thailand went off the runway, hit an embankment and caught fire.
According to Boeing, which bought McDonnell Douglas in 1997, the MD-80 series jets have a fatal crash about once every 3 million departures.
Some newer Boeing models, such as the 767, and the Airbus 320 series have better records, according to Boeing figures.
But according to Boeing, the Airbus 300-600 series has a fatal accident rate about twice that of the MD-80, the rate for early model Boeing 737s is nearly three times as bad, and the rate for Boeing jumbo jet 747s is about four times that of the MD-80.
American Airlines, the largest U.S. carrier, operates 300 MD-80 series planes, the largest such fleet in the world. Delta Air Lines Inc. has the second-largest fleet, with about 120 MD-80 series planes according to Boeing. Spanair has about 30, and its owner, Swedish carrier SAS AB, about 50.
Earlier this year, Fort Worth, Texas-based American had to ground its entire MD-80 fleet to fix electrical wiring in the wheel wells, a move that forced the cancellation of more than 3,000 flights. Chief Executive Gerard Arpey said that the planes' safety "was never at issue," but that mechanics had not secured bundles of wires to the precise standards of the Federal Aviation Administration.
Since then, American has sped up plans to replace some of its MD-80s _ which are notorious gas-guzzlers _ with more fuel-efficient Boeing 737 aircraft.
The MD-80 is a mid-size jetliner that seats up to 172 passengers. Two engines are mounted along the sides of the fuselage just in front of the tail.
They are designed to be able to fly on one engine, which happened this month when an American Airlines jet taking off from LaGuardia Airport in New York lost power in one engine and made an emergency landing at nearby Kennedy Airport.
McDonnell Douglas produced nearly 1,200 planes in the MD-80 series, of which 1,100 are still in use, according to Boeing.
McDonnell Douglas had stopped production of all but one of the models when Boeing bought its smaller rival in 1997, and it closed down that line two years later to focus on newer models of its own popular midrange jet, the 737.