Japan Air Lines Cargo Flight 46E

N473EV, the aircraft involved, seen at Glasgow Airport, in the early 1990s
Incident
Date	31 March 1993
Summary	Severe turbulence resulting in detachment of engine No. 2
Site	Over Alaska, United States 61°10′N 149°56′W / 61.167°N 149.933°W / 61.167; -149.933
Aircraft
Aircraft type	Boeing 747-121F
Operator	Japan Air Lines on behalf of Evergreen International Airlines
Call sign	JAPAN AIR 46 ECHO
Registration	N473EV
Flight origin	Anchorage International Airport, Anchorage, Alaska, United States
Destination	O'Hare International Airport, Chicago, Illinois, United States
Passengers	2
Crew	3
Fatalities	0
Injuries	0
Survivors	5

Japan Air Lines Cargo Flight 46E was a scheduled cargo flight on 31 March 1993, operated by Evergreen International Airlines, on behalf of Japan Air Lines, from Anchorage International Airport, in Anchorage, Alaska, to O'Hare International Airport, in Chicago. After departure, while climbing through 2,000 feet, the pylon for engine two detached, causing the whole engine to fall off the wing. The pilots managed to land the 747 back at Anchorage without further incident.

The NTSB concluded that the lateral separation of the No. 2 engine pylon was possibly due to an encounter with severe or possibly extreme turbulence that resulted in dynamic multi-axis lateral loadings that exceeded the ultimate Iateral load-carrying capability of the pylon, which was already reduced by the presence of the fatigue crack near the forward end of the pylon's forward firewall web.

Aircraft and crew

The aircraft was a 23-year-old Boeing 747–121 registered as N473EV that first flew in 1970 as a passenger aircraft. It had been previously operated by Pan Am, and TWA before being converted into a freighter and delivered to Evergreen International Airlines in December 1988.^[1] The aircraft was powered by four Pratt & Whitney JT9D-7D turbofan engines.^{[2]: 8 [3]}

The 42-year-old male captain had been with Evergreen International Airlines since 1987 and had logged more than 10,000 flight hours, including 750 hours on the Boeing 747. The 47-year-old male first officer had been with the airline since 1991 and 10,500 flight hours, 600 of them on the Boeing 747. The 33-year-old female flight engineer had been with Evergreen since 1989 and had 2,600 flight hours. She was the most experienced on the Boeing 747, having logged 1,201 hours on it.^{[2]: 6, 8}

Flight

JAL Flight 46E departed Anchorage about 12:24 local time. The flight release/weather package provided to the pilots by Evergreen operations contained a forecast for severe turbulence and indicated that severe turbulence was reported by other large airplanes. As Flight 46E taxied onto the runway to await its takeoff clearance, the local controller informed "the flight crew that the pilot of another Evergreen Boeing 747 reported severe turbulence at 2,500 feet (760 m) while climbing out from runway 06R." After takeoff, at an altitude of about 2,000 feet (610 m), the airplane experienced an uncommanded left bank of approximately 50 degrees.

While the desired airspeed was 183 knots (339 km/h; 211 mph), the airspeed fluctuated about 75 knots (139 km/h; 86 mph) from a high of 245 knots (454 km/h; 282 mph) to a low of 170 knots (310 km/h; 200 mph). Shortly thereafter, the flight crew reported a "huge" yaw, the No. 2 throttle slammed to its aft stop, the No. 2 reverser indication showed thrust reverser deployment, and the No. 2 engine electrical bus failed. Several witnesses on the ground reported that the airplane experienced several severe pitch and roll oscillations before the engine separated. Shortly after the engine separated from the airplane, the flight crew declared an emergency, and the captain initiated a large radius turn to the left to return and land on runway 06R. The No. 1 engine was maintained at emergency/maximum power. While on the downwind portion of the landing pattern, bank angles momentarily exceeded 48 degrees, alternating with wings level. At about 12:45, Flight 46E advised the tower that they were on the runway.^[2]

Investigation

Investigators from the National Transportation Safety Board (NTSB), led the investigation. They discovered that there were multiple detachments of the pylon for engine two, which led to the subsequent detachment of the whole engine. Investigators also discovered that the direction of the detachment was outboard. It is likely that the reason for the engine detachment was due to the turbulence from the Alaskan Mountains the plane experienced as it climbed through 2,000 feet. The turbulence would've stressed the engine pylon. There was no sign of the same crack on other 747 pylons after Flight 46E's incident.

Prior to JAL46E's takeoff, another Evergreen 747 also on behalf operation with Japan Air Lines, JAL42E, also experienced minor damage. In response to the incident, the NTSB recommended that the FAA consider modifying the departure routes at Anchorage.^[2]

Aftermath

N473EV was repaired and returned to service after the incident and kept flying for Evergreen International Airlines until 1998. The plane was scrapped in 2001.^[4]

In popular culture

Prior to this incident the aircraft in question was chartered for the filming of the action movie Die Hard 2, which featured a scene whereby a character was ingested into the number 2 engine.