AVIATION/ REMEMBERING LAUDA AIR FL004

Memorial services are being held today to commemorate the lives of those who perished 20 years ago today on LAUDA AIR Flight 004 in Thailand. The disaster ranks as one of the top 25 worst accidents in the history of aviation. On May 26, 1991, Lauda Flight 004 was on International Service from Hong Kong to Vienna, Austria, with a stop in Bangkok, Thailand. The route was being flown by a Boeing 767-300, registration OE-LAV and pictured above, that had the nickname of Wolfgang Amadeus Mozart. The service from Hong Kong to Bangkok was completed without incident. Flight 004 then departed from Old Bangkok International Airport at 11:02pm with 213 passengers and 10 crew members onboard. Just 6 minutes later, at 11:08pm, the 2 Pilots received a REV ISLN advisory warning indicating that a possible system failure would cause the thrust reverser on the No.1 engine to deploy inflight. This indication appears when a fault has been detected in the thrust reverser system. The Co-Pilot consulted the aircraft's Quick Reference Handbook, which said: "Additional systems failures may cause in- flight deployment" and "Expect normal reverser operation after landing." The Captain then said: "....its not just on, its coming on and off," and, "...its just an advisory thing...," followed by "could be some moisture in there or something." At 11:12pm, the Co-Pilot advised the Captain that there was need for, "a little bit of rudder trim to the left." At 11:17pm, now 15 minutes after departure, the thrust reverser on the No.1 engine deployed while the plane was over mountainous jungle terrain in the border area between Suphanburi and Uthai Thani provinces, Thailand. The last recorded words from the cockpit came from the Co-Pilot, who said: "Oh, reverser's deployed!". The 767 then stalled in midair and entered an uncontrolled descent. Buffeting, maneuvering overload, and excessive speed caused pieces of the rudder and the left elevator to separate. This was followed by the down-and-aft separation of most of the right horizontal stabilizer from maneuvering overloads, as the crew attempted to control the 767 and arrest the high-speed descent. A torsional overload then caused the separation of the vertical and left horizontal stabilizers. The loss of the tail resulted in a sharp nose-over of the airplane, producing excessive negative loading of the wing. A downward wing failure was probably followed by the breakup of the fuselage. The complete breakup of the tail, wing, and fuselage occurred in a matter of seconds. The wreckage fell in mountainous jungle terrain. Most of the wreckage was scattered over a remote forest area of about 1km in size.None of the 223 passengers and crew onboard Flight 004 survived. It was the 1st fatal crash of a Boeing 767. The accident remains the deadliest aviation disaster on Thai soil to date. The Accident Investigation Committee of the Government of Thailand determined the Probable Cause of the accident to be uncommanded inflight deployment of the left engine thrust reverser, which resulted in loss of flight path control. The specific cause of the thrust reverser deployment was not positively identified. The crash site, which is in Phu Toei National Park and accessible visitors, a shrine was later erected to commemorate Flight 004. Another memorial and cemetery is located near Ban Tha Sadet, some 90 km away in Amphoe Mueang Suphanburi.