2011 Pawan Hans Mi-17 crash

On 19 April 2011, a Mil Mi-17 helicopter operated by Pawan Hans crashed near the town of Tawang, India, killing 17 of 23 people on board.

Accident
The helicopter had taken off at 12:45 pm from Borjhar Airport in Assam on an internal flight to the town of Tawang, in Tawang district, India. On board were 18 passengers and 5 crew. At around 13:50 pm, the helicopter arrived at destination, but while attempting to land at Tawang Civil helipad, which is located on top of a hill, the Mi-17 crashed into a gorge and caught fire.

Aircraft
The aircraft involved, a Mil Mi-17, registered VT-PHF, was also involved in a previous emergency landing in the same region.

Casualties
Seventeen of the 23 on board were killed, including three crew members. Out of the 17, two were minors. Two passengers survived the crash initially, but later died due to injuries from the post-crash fire.

Investigation
An official in the Directorate General of Civil Aviation (DGCA) said that as per initial reports the helicopter crash-landed "due to likely wind shear and downdraft while landing and caught fire on impact to the ground".

Probable cause
The Indian Directorate General of Civil Aviation (DGCA) release their final report stated that the cause of the accident was because the helicopter missed the helipad at about 27 meters and drops from the helipad height by about 1 meter. The left oleo leg was tear off apart due to the forward movement and the slow rate of descent. This factor produces a slight left bank to the helicopter. At this time the flight controls of the helicopter were increased to 13.8 degrees in order to increase the thrust of the rotor. This factors combined increased the vertical thrust of the helicopter to such a range that the bank increased from 5 degrees to 85 degrees in 1 second. The helicopter hit the beginning of the helipad with is main rotors causing them to break. Adjacent to the helipad it was present a slope, in which the helicopter as skidded and almost turned over is back after the accident. Subsequently, the helicopter, it caught fire and was totally destroyed.

Contributory factors
In the final report there are contributing factors as well which are:


 * The inadequate use of the Met resources that are contributed to the accident. The fight crew are disregard with the local QNH and temperature given by Tawang Air Traffic Controller.
 * The other contributing factor was that the Aircraft gross weight (AGW) was above the agreed limit wrote in the Flight Manual for Category ‘A’ operation.