The 1971 Boeing 747 that crashed into the Atlantic on Wednesday night was reliable, according to maintenance records kept in a Federal Aviation Administration database examined by The Times.
Despite its long service, only once in the last eight years was the plane forced to turn back because of a mechanical problem. The nose gear wouldn't retract after taking off in July 1989. The replacement of a malfunctioning valve solved the problem.
Only five other 747s, according to the database, had accumulated more than the 87,000-plus hours and 16,000-plus takeoff-landing cycles recorded for the TWA plane that exploded in midair off Long Island, N.Y. Four of those also were flown by TWA. The fifth belonged to Tower Air.
The maintenance histories of airplanes and many of their individual parts are detailed in "service difficulty reports" filed by aircraft mechanics and stored in the FAA database. The information can highlight recurring problems in a particular model or in a particular part used in various models. But no such problems were highlighted in the 42 service difficulty reports filed between December 1988 and August 1995 on the plane that crashed.
Twenty-five of the reports documented repairs made during two separate airframe overhauls in 1990 and 1992. They concerned a variety of small cracks, a couple of small broken frame members and some minor corrosion. One of the cracks, an inch long, was in a fuel tank.
Engine problems were reported only twice in the eight-year maintenance history recounted in the database.
In February 1994, the two outboard engines "spooled down" in flight but were quickly restarted with normal procedures. A number of fuel-system checks were performed after the flight, including bleeding the system in case an air bubble was blocking it. No malfunctioning parts were found.
The last report on the plane that flew as TWA Flight 800 was in August 1995, when the No. 1 engine was shut down in flight because of a low oil level. A leaking oil line was replaced.
The rest of the maintenance history may have caused an anxious moment or two, but did not pose a safety threat. Twice, electric light sockets in the cabin shorted; a pressurized drinking water tank broke apart during cabin modification work; an odor in a galley cart was traced to a defective cable. Two other galley carts overheated from an electrical short over the years. And so did a galley oven.
The No. 2 engine was repaired once because an oil filter bypass light came on. A waste container in a lavatory smoldered and was doused with a fire extinguisher. And once, the emergency exit lights failed at one door, requiring replacement of a malfunctioning connector.
No other major U.S. airline flies a fleet of Boeing 747s with as many hours on them as does TWA, according to the FAA database.
The Times' examination of the service difficulty reports found maintenance records for 18 TWA 747s. One had nearly 100,000 hours and nearly 18,000 takeoff-landing cycles at its last database entry in February 1995.
Three others had more than 90,000 hours of operation; five had more than 80,000 hours, and seven had more than 70,000 hours. The freshest plane in the fleet had more than 56,000 hours.
In February, TWA placed a $1-billion order with Boeing Co. for 20 new jetliners.