Lauda Air Flight 004
Lauda Air Flight 004 was an international passenger flight that crashed due to a
thrust reverser deployment of the number one
engine, in flight.
On
May 26,
1991, about 2310 local time, Flight 004 (originating from
Hong Kong's
Kai Tak Airport), a
Boeing B-767-3Z9ER, registration OE-LAV, took off from
Bangkok International Airport for its flight to
Vienna International Airport with 213 passengers and 10 crew, under the command of Capt. Thomas J. Welch and First Officer Josef Thurner.
At 2322, Welch and Thurner received a visual advisory warning indicating that a possible system failure would cause the thrust reverser on the No. 1 engine to deploy in flight. Because the Emergency/Malfunction Checklist indicated that no action was necessary, Welch and Thurner didn't take any action.
At 2331, the thrust reverser on the No. 1 engine deployed while the plane was over the jungle near Ban Nong Rong (
Uthai Thani Province), Thailand. Thurner's last recorded words are reported to have been, "Reversers deployed!"
The 767 stalled in mid-air and disintegrated at 4000 ft (1200 m). None of the 223 passengers and crew survived. The explosion remains the worst aviation disaster on Thai soil to date.
Upon hearing of the crash,
Niki Lauda, retired
Formula 1 race driver and owner of the airline, flew to
Thailand and personally visited the crash site, turning up information that led to the accident's cause, which was the failure of the thrust reverser isolation valve. He tested his findings in a Boeing 767 simulator in
England and revealed those findings in a press conference shortly thereafter. A subsequent official investigation corroborated Lauda's findings, leading Boeing to modify the thrust reverser system to prevent similar occurrences.
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Hughes XF-11 - this aircraft also crashed due to a thrust reverser (in this case a reversible-pitch
propeller) inadvertently deploying in flight.
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PlaneCrashInfo.Com - Lauda Air Flight 004*
Aviation Accident Database - Lauda Air Flight 004*
- Accident Report
