Safety Board Looking At Widely Used Jet Engine
WASHINGTON (AP) _ One of aviation’s most widely used jet engines, the Pratt & Whitney JT8D, is again coming under scrutiny for a possible safety problem.
The National Transportation Safety Board on Tuesday urged airlines to inspect more than 900 of the engines, those of the 200-series, following three incidents in which the engines malfunctioned in recent months.
In each case the planes, which are designed to operate with one of their two engines out, landed safely.
The JT8D engines cited by the NTSB are believed to be used primarily on the twin-engine McDonnell-Douglas MD-80 series aircraft which is flown by a dozen U.S. airlines and 14 foreign carriers, according to the NTSB.
The safety board asked the Federal Aviation Administration to ″establish an appropriate inspection program″ for the engine. The recommendation grew out of the NTSB’s probe into a March 23 incident that involved an American Airlines MD-80 aircraft making an approach to Minneapolis.
The board said a series of internal vanes that direct air into the turbine blades in one of the engines stalled. The engine was shut down and the aircraft made a safe landing, the investigators said.
Two similar engine problems were reported last December involving another American Airlines plane and a Muse Airlines aircraft. Another such incident involving a Pacific Southwest Airlines plane occurred in March 1985, according to the board.
The safety board asked the FAA to direct an inspection of the engine parts involved in the four engine breakups. There are an estimated 934 such 200- series engines, and some already are believed to have undergone modifications to deal with the problem, the board said.
In all, there are more than 9,000 model JT8D engines in use by U.S. airlines and several thousand more by foreign carriers. Nearly one of every two commercial U.S. carriers is powered by the engine, although not necessarily the 200-series, including the Boeing 727, Boeing 737 and McDonnell-Douglas DC-9 as well as its later version, the MD-80.
The engine for years was considered to have an outstanding safety record. In 1985, a number of safety questions emerged about the engine after a series of engine breakups related to two unrelated problems.
The engine attracted widespread attention because of a spacer break-up problem in a number of incidents, including the 1985 crash of a Midwest Express DC-9 that killed 33 people in Milwaukee.
Questions also were raised in 1985 and 1986 about cracking in the combustion chamber of the engine. A failure inside the combustion chamber has been blamed for the engine breakup and fire that killed 55 people aboard a British Airtours DC-9 in Manchester, England, in 1985.