General Bipin Rawat copter crash: What is Controlled Flight into Terrain?

The Indian Air Force (IAF) said on Friday that Chief of Defence Staff (CDS) General Bipin Rawat's chopper had crashed due to "unexpected change in weather conditions" leading to "spatial disorientation of the pilot".

India's CDS was aboard the Mi-17 V5 helicopter when it crashed near Coonoor in Tamil Nadu. Thirteen people died in the crash including General Rawat's wife Madhulika.

Also Read: General Rawat copter crash: Probe committee says weather change disoriented pilot

"The accident was a result of entry into clouds due to unexpected change in weather conditions in the valley. This led to spatial disorientation of the pilot resulting in Controlled Flight into Terrain (CFIT)," the IAF said.

What is Controlled Flight into Terrain?

Controlled Flight into Terrain(CFIT) is defined as unintentional collision with the terrain by an aircraft as it hits the ground, mountain, waterbody or an obstacle while it is in flight.

CFIT scenario occurs when the pilot is in control of an airworthy aircraft however the crash occurs since the pilot is unaware of the danger until it is too late. In most cases, CFIT accidents take place during the landing phase.    

The weather, turbulence and snow on the runway are contributing factors towards CFIT. According to International Air Transport Association (IATA), CFIT is not the most frequent of accident categories. However, it leads to a substantial number of fatalities.

What are the measures taken to prevent CFIT?

According to IATA, Ground Proximity Warning System (GPWS) was introduced in the 1970s to provide warnings to pilots when the aircraft is in potentially hazardous terrain. 

A new technology called Enhanced Ground Proximity Warning System (EGWPS) also known as Terrain Awareness and Warning System (TAWS) was introduced to help pilots. It combined worldwide digital terrain database with an accurate navigation system using the Global Positioning System (GPS).

(With inputs from Agencies)