NYC04TA103

During cruise flight, the crewmembers heard a "bang" from the rear of the cabin, and the airplane momentarily shuddered and bounced. After landing uneventfully at their destination airport, the crewmembers observed that the number two right engine cowling had separated and struck the right inboard elevator. Inspection of the airplane revealed that the engine cowling upper forward hinge required three bolts. However, only one bolt remained attached, and there was no evidence that the other two bolts tore away during flight. Fretting was observed in the area of the bolt holes, consistent with an oscillation over a period of time, due to the absence of two bolts. The airliner maintenance manual required a general inspection of the area, but did not specifically mention cowling hinge bolts. In addition, the hinges were located in an area that was not easily accessible to maintenance personnel.

On April 10, 2004, about 2258 eastern daylight time, a McDonnell Douglas DC-10-30, N14075, operated by World Airways Inc., as flight 725, was substantially damaged during cruise flight over the Atlantic Ocean. The 3 cockpit crewmembers, 9 cabin crewmembers, and 240 passengers were not injured. Night visual meteorological conditions prevailed for the flight that departed Naples, Italy; destined for Norfolk Naval Station (NGU), Norfolk, Virginia. An instrument flight rules flight plan was filed for the public use non-scheduled passenger flight.

The captain reported that the airplane was in cruise flight at 32,000 feet. The airplane "shuddered and bounced" for a half-second, and then returned to stable flight. At that time, a flight attendant heard a "bang" from the rear of the airplane. The cockpit crew then felt a slight vibration, and noted a fuel burn of approximately 1,000 pounds per hour more than expected. However, all cockpit controls and instruments appeared normal.

The flight proceeded to NGU and landed uneventfully about 0300, on April 11. A subsequent inspection of the airplane revealed that the right engine cowling had separated from the number two engine. Approximately 40 percent of the right inboard elevator had separated, consistent with the elevator being struck by the engine cowling.

Further inspection of the airplane by a Federal Aviation Administration (FAA) investigator revealed that the engine cowling upper forward hinge required three bolts. However, only one bolt remained attached, and the investigator did not observe any evidence that the other two bolts tore away during flight. The investigator also noted fretting in the area of the bolt holes, consistent with an oscillation over a period of time, due to the absence of two bolts.

The FAA investigator added that the airliner maintenance manual required a general inspection of the area, but did not specifically mention cowling hinge bolts. In addition, the hinges were located in an area that was not easily accessible to maintenance personnel. The investigator subsequently submitted a safety recommendation to have the cowling hinge bolts inspected every "D" check.