Widespread Respect for Engine Type Aboard Flight 1141
WASHINGTON (AP) _ Investigators examining the Pratt & Whitney JT8D engine as a possible cause of Wednesday’s Delta Air Lines crash are scrutinizing a powerplant with which the aircraft industry has conducted a quarter-century love affair.
Almost 12,000 of the engines have been sold since the Federal Aviation Administration approved them in 1964. Today, they are used by 350 airlines, governments and corporations and are more widely utilized than all other commercial jet engines combined, Pratt & Whitney spokesman David Long said Thursday.
″It’s one of the more reliable engines on the market today,″ said James P. McFadden, aerospace analyst for Merrill Lynch Capital Markets in New York.
Even before Delta Flight 1141 plunged to the ground Wednesday shortly after takeoff from Dallas-Fort Worth International Airport, the government had named the JT8D as contributing to two major accidents that occurred in 1985.
On Thursday, National Transportation Safety Board member Lee Dickinson said recordings of cockpit conversations on Flight 1141 before the accident revealed discussions of engine problems and noises indicating a stall may have been imminent.
Witnesses reported seeing flames streaming from an engine just before the crash. Thirteen people were killed, but nearly 100 survived the fiery wreck.
Despite those blemishes, the engine is so reliable the government uses the frequency rate with which they break down in flight as the benchmark against which new engines are measured.
So far this year, the JT8Ds have shut down in flight 0.012 times per 1,000 hours of flight, Long said from Pratt & Whitney offices in East Hartford, Conn.
According to Jay Pardee, manager of the FAA’s engine certification office in Burlington, Mass., some engines have been known to shut down one or two times per 1,000 hours of flight.
″It’s a goal we require all new technologies to meet,″ Pardee said of the JT8D’s performance statistics.
All Boeing 727s - Flight 1141 was a 727 - use three of the engines mounted on the rear of the aircraft. They are also used on many Boeing 737s and McDonnell Douglas DC-9s. In addition, McDonnell Douglas MD-80s use JT8D-200s, an advanced model of the engine.
Pratt & Whitney estimates that in all, the engines have flown more than 400 million hours in nearly a quarter-century of service.
″For an engine to be around for 25 years says a lot about its acceptance,″ said McFadden of Merrill Lynch.
But problems with the JT8D have been blamed by government officials as contributing to two major air accidents in 1985.
In Manchester, England, in August of that year, the engine’s combustion chamber cracked and burned through on a British AirTours jetliner during takeoff. Fifty-five people died when the plane caught fire.
The accident sparked widespread inspections of combustion chambers of older, high-use JT8D engines as well as a requirement for more frequent inspections to check for cracks.
The next month, a Midwest Express DC-9 crashed in Milwaukee, killing 31 people, in an accident that was blamed on a fracture of the engine spacers, which separate the turbine blades. Afterward, the FAA ordered owners of planes with the engines to conduct inspections looking for cracks, and to replace the spacers periodically.