CDS Bipin Rawat's chopper crash black box recovered: What is a black box?

India's top-most defence official, General Rawat, was on board the helicopter that took off from the Sulur IAF Station in Coimbatore for the Defence Staff College in Wellington when it crashed midway.

Investigators on Thursday recovered the black box from the crashed Indian Air Force Mi-17V5 helicopter that killed Chief of Defence Staff General Bipin Rawat, his wife Madhulika Rawat and 11 others in Tamil Nadu's Coonoor. The black box also known as a flight recorder will provide crucial details of the final minutes before the tragic accident.

Official sources said the black box was retrieved after authorities expanded the search area from 300 metres to one km of the accident spot.