Lauda Air Flight NG 104, a Boeing 767-300 ER of Austrian nationality was on a scheduled passenger flight Hong Kong-Bangkok-Vienna, Austria. NG 004 departed Hong Kong Airport on May 26, 1991 , and made an intermediate landing at Bangkok Airport. The flight departed Bangkok Airport at 1602 hours. The airplane disappeared from air traffic radar at 1617 hours about 94 nautical miles northwest of Bangkok. The probable cause of this accident is attributed to an un-commanded in-flight deployment of the left engine thrust reverser. All 223 people on board died in the accident.