What happened
On November 28, 2010, an Evergreen International Airlines, Inc. cargo flight, operating a Boeing 747-200 registered N482EV, departed from runway 36 at Chubu Centrair International Airport. The flight was scheduled to proceed to Anchorage, USA. Shortly after takeoff, while climbing through approximately 3,500 feet, the crew experienced intense aircraft vibrations accompanied by a significant drop in thrust indications on the No. 2 engine.
Following the onset of the vibrations, the flight crew initiated emergency procedures, which included shutting down the malfunctioning engine and performing a fuel jettison to reach a safe landing weight. The aircraft returned to Chubu Centrair International Airport and landed safely at 07:14 JST. There were no injuries among the three crew members on board.
The investigation
The Japan Transport Safety Board (JTSB) examined the engine and airframe to determine the source of the vibration and the extent of the damage. Inspections of the No. 2 engine revealed extensive internal destruction. While the high-pressure turbine and combustion chamber appeared normal, the low-pressure turbine (LPT) section sustained severe damage. Specifically, investigators found that the 1st stage LPT rotor blades had fractured.
This failure caused a chain reaction of damage to downstream components, including the LPT5 and LPT6 blades, stator vanes, and the turbine exhaust case struts. The force of the failure was sufficient to cause small metallic fragments to be expelled through the exhaust, resulting in a 1 cm rupture in the engine case and impact damage to the aircraft' and the inboard aileron fairings.