New Delhi: Defence officials on Thursday retrieved the Flight Data Recorder, more popularly known as ‘Black Box’, of the ill-fated Indian Air Force helicopter that crashed near here on Wednesday, killing Chief of Defence Staff, General Bipin Rawat and 12 others.
Official sources said the black box was retrieved in the wake of authorities expanding the search area from 300 metres to one km from the accident spot.
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.
Rawat was on his way to the Defence Services Staff College (DSSC), Wellington to address the faculty and student officers of the staff course when the fatal mishap happened in the Katteri-Nanchappanchathram area.
IAF chief, Air Chief Marshal V R Chaudhari visited the site of the helicopter crash on Thursday and along with senior officials, inspected the area, official sources said.
WHAT IS A BLACK BOX?
A black box is a device that is installed in aircraft to help investigators in case of unfortunate accidents. Similar to a hard disk, the black box is a highly protective machine that records all flight data and conversations in the cockpit. Apart from recording cockpit conversations, the recorder also holds information on automatic computer announcements, radio traffic, discussions with the crew and announcements to the passengers.
According to experts, the flight recorder also stores private conversations between the pilots, making it crucial in case of a crash as it could provide key details about the developments leading up to an accident.
There are two types of flight recording devices: the Flight Data Recorder (FDR) that stores all the recent history of the flight through the recording of dozens of parameters collected multiple times per second and the Cockpit Voice Recorder (CVR) that records cockpit sound including pilot conversations.
WHY IS IT CALLED BLACK BOX?
The black box these days is in bright orange colour, which makes it easier to spot amid the wrangled mess of the crash. However, when these recorders were first introduced, their black colour stuck with the name. Double wrapped in a corrosion-resistant stainless-steel container with high-temperature insulation, the black box is designed to withstand the harshest crashes — on the land and over seas.
CAN BE RECOVERED FROM SEAS
While crashes can happen anywhere both on land and over seas, the flight recorder is designed in a way that it can be recovered from underwater locations as well. The device sends out a signal on contact with saltwater that can be picked up within a radius of about two kilometres. The device can withstand water pressure found in depths of up to 6,000 meters.
