Mangalore, May 25: After three days of intense search, the missing part of the black box of the ill-fated Air India flight has been found at the crash site.
The Digital Flight Data Recorder of the crashed Air India plane will give key details of the conversation between the Air Traffic Control (ATC) and the pilot and will help investigators ascertain what actually went wrong.
Altogether 158 people were killed after the Air India plane IX 812 overshot the runway by 2,000 feet, going off the edge of Mangalore’s table-top airport.
The plane was flying from Dubai to Mangalore with 160 passengers and six crew members on board.
Over-speeding may be the cause crash
Initial investigations into Saturday’s Mangalore air accident suggest that the Air India Express aircraft might have been flying at a speed higher than the normally prescribed limit of around 140 nautical miles at the time of landing, with the internationally accepted glide angle of three degrees.
Officials involved in the investigation are, however, yet to arrive at any conclusion about the exact speed of the ill-fated plane when it made the touchdown at the table-top runway at Bajpe. The officials said they would have to decode data from the Black Box to firmly establish the exact speed. The Black Box is yet to be retrieved from the accident site.
Landing at higher speeds than the prescribed limit usually causes the aircraft to overshoot the touchdown zone while landing. On Saturday, the plane is estimated to have overshot by 2,000 feet as it made the touchdown at the 8,000 -foot runway. The officials said that the pilot might have applied sudden brake after he sensed trouble, leading to the plane to skid off the runway.
Had the plane overshot up 1,000 feet, it would have still made a safe landing as this is considered to be acceptable, though the safest overshot limit is not more than 500 feet in a table-top runway like the one in Mangalore, said an official.
He added that the exact explanation of the tragedy must wait until a detailed analysis is carried out based on data that would be available from the cockpit voice recorder (CVR) which was retrieved from the site on Sunday and the more crucial Black Box.
The CVR and the Digital Flight Data Acquisition Unit (DFDAU), which record the cockpit audio and most of the aircraft’s technical details, would be brought to the headquarters of the Directorate-General of Civil Aviation (DGCA) here for analysis, the official said.
The CVR and the DFDAU, which were retrieved from the debris in a burnt condition, will be analysed by technical experts of the DGCA’s Air Safety Division. While the CVR captures radio transmissions and sounds in the cockpit such as the pilots’ voices and engine noise, the DFDAU records all parameters of a short-duration flight.
However, since the two crucial devices are damaged, efforts would be made to take the electronic chips of the CVR and insert them in a serviceable unit in order to retrieve the information, the officials said. Analysis of CVR and DFDAU is expected to take at least a fortnight. The analysis of all records and documents collected would take a couple of weeks more, sources said.
Meanwhile, a preliminary examination of the audio taped conversation between the Air Traffic Control in Mangalore airport and the pilots of the Boeing 737-800 plane moments before the crash has been carried out, they said.
Four teams of investigators from engineering, operations, ATC and aerodrome units have made several rounds of inspection of the wreckage, the runway and the adjoining areas of the accident site.
These teams have also collected a large number of materials for evidence through extensive search of the aerodrome, runway and navigational facilities, the sources said.
DGCA’s mandate not adhered to Air India Express flight IX-812, which crashed in Mangalore on Saturday, did not have Global Navigation Satellite System (GNSS) equipment installed in it, despite a Director General of Civil Aviation (DGCA) circular mandating airlines operating in India to do so.
In February this year, the DGCA issued an ‘operations circular’ to all airlines, advising them to install GNSS equipment to ensure navigation accuracy.