Chopper crash: Mi-17V5 cockpit voice recorder, flight Data Recorder found

New Delhi, Dec 09: The cockpit voice recorder and flight data recorder popularly known as 'Black Box', of the ill-fated Mi-17 helicopter that crashed near Coonoor in Ooty on Wednesday, killing Chief of Defence Staff, General Bipin Rawat and 12 others was retrieved.

The black box of the crashed Mi-17VH helicopter was found after its search area was expanded from 300 metres to one km from the accident spot by the Defence officials.

Two boxes including the flight data recorder were recovered from the site, official sources said, adding, they are likely to be taken to Delhi or Bengaluru to ascertain the cause of the crash.

The black box would provide crucial data on the chain of events leading to the tragedy on the hills on Wednesday when the 63-year old Rawat, the country's first CDS, his wife and 11 others were killed after the Mi-17VH helicopter they were travelling in crashed and went up in flames, leaving only one survivor.

India's Chief of Defence Staff General Bipin Rawat, his wife Madhulika Rawat and 11 other defence personnel died after a military helicopter carrying them crashed near Coonoor in Tamil Nadu on Wednesday.

When a crash happens, the black box is located on a priority basis to understand what actually caused the crash.

What is the main difference between a cockpit voice recorder and a digital flight data recorder?

The flight data recorder (FDR) preserves the recent history of the flight through the recording of dozens of parameters collected several times per second; the cockpit voice recorder (CVR) preserves the recent history of the sounds in the cockpit, including the conversation of the pilots. The two devices may be combined into a single unit. Together, the FDR and CVR objectively document the aircraft's flight history, which may assist in any later investigation.

The two flight recorders are required by international regulation, overseen by the International Civil Aviation Organization, to be capable of surviving the conditions likely to be encountered in a severe aircraft accident.

For this reason, they are typically specified to withstand an impact of 3400 g and temperatures of over 1,000 °C (1,830 °F), as required by EUROCAE ED-112.