Are 747s Safe to Fly?

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BOEING'S FAMOUS JUMBO JET, THE 747, HAS BEEN THE KING OF THE SKIES since it went into commercial service in 1970. More than 900 of its four models still form the vanguard of long-range airline fleets around the world. The 747 has enjoyed an outstanding safety record: only 11 have crashed in 22 years.

In the past 10 months, however, two 747 cargo planes, model 200, have gone down in alarmingly similar circumstances. A China Airlines plane lost both its starboard engines shortly after takeoff from Taipei last December. Over Amsterdam last week, the engines on the El Al cargo flight's right wing also dropped off.

Though investigators do not know for certain what caused either of these crashes, they suspect that the steel pins that attach the engines to the wing may have failed. Even before the China Airlines accident, Boeing was concerned about wear and tear on the so-called fuse pins, 4-in.-long cylinders of machined steel designed to hold each engine securely under the wing. Each engine has four pins. Up to a year ago, airlines had found deterioration in seven pins. Since then, eight more weakened pins have been discovered. The problem seems to begin with pitting and corrosion that, as it worsens, weakens the metal pin and causes cracks.

None of those 15 damaged pins have caused an accident, but their discovery prompted Boeing to call a meeting to discuss fuse-pin inspection with airlines using 747s and the Federal Aviation Administration. Boeing told officials of large and small airlines about the problem at a meeting of the Air Transport Association of America in Seattle last month. "We gave the operators some history of the problem and how the inspections should be made," says Boeing spokesman Christopher Villiers.

After last week's crash, Boeing issued a service bulletin on 747 models 100, 200 and 300 carrying Pratt & Whitney or Rolls-Royce engines, both of which use the fuse-pin assembly being investigated. The company said it had not located any of the pins from either crash but had still "decided it was prudent to request an inspection." The FAA followed up with a mandatory directive to airlines worldwide requiring them to inspect the pins. The order does not ^ cover the newest 747, model 400, which uses a different engine-attachment system.

Despite the logical suspicion that fuse pins may have failed in the two recent crashes, no one is calling the mainstay of international air transportation, the 747, unsafe. The plane has flown billions of problem-free passenger-miles. Indeed, when the U.S. Air Force and White House security officers painstakingly checked airplane safety records before selecting the new presidential carrier, Air Force One, they settled on the 747-200.