Indian Airlines Flight 257
|Date||16 August 1991|
|Summary||Controlled flight into terrain|
|Site||Imphal, Manipur, India
|Aircraft type||Boeing 737-2A8|
The flight, operating on the Calcutta-Imphal route, crashed into Thangjing hills, about 37 kilometres (23 mi) south-west of the Imphal airport. The aircraft had started the short flight from Calcutta around 12:00 pm and it began a descent into Imphal airport at around 12:41 pm. Visibility at that time was 7 kilometres (4.3 mi). Imphal airport lost contact with the aircraft just after 12:45, at 1,500 metres (4,900 ft) altitude on the Instrument Landing System. The search and rescue efforts were hampered by bad weather conditions and a hilly and slushy terrain.
The probable cause of the crash was attributed to an "error on the part of the Pilot-in-Command in not adhering to the operational flight plan and ILS let down chart and not realizing that his early descent to 10,000 feet (3,000 m) and turning right for outbound leg without reporting overhead VOR would result in loss of time reference and as such misplace him in the hilly terrain. The Pilot-in-Command's action may have been influenced by his extreme familiarity with the terrain".