Ahmedabad Plane Crash: Both the FDR and CVR, Together Called “Black Box,” Recovered
Manas Dasgupta
NEW DELHI, June 16: The authorities have confirmed that both the “black boxes,” the data recorders of the ill-fated London-bound Air India plane from Ahmedabad, which lost thrust 36 seconds after take-off and crashed into residential buildings bordering the airport, have been recovered from the accident site.
The Aircraft Accident Investigation Bureau (AAIB) had earlier confirmed that the Flight Data Recorder (FDR) of the ill-fated plane was found. The officials informed Mr PK Mishra, the principal secretary to the Prime Minister Narendra Modi, that the Cockpit Voice Recorder (CVR) have also been located at the crash site.
Mr Mishra was in Ahmedabad on Sunday and inspected the site where the Air India plane crashed in Ahmedabad on June 12 and also visited the civil hospital where the injured persons are undergoing treatment. With the finding of both black boxes of the plane, it would be easy for investigators to ascertain the cause of the crash.
All but one of the 242 passengers and crew on board the Boeing 787-8 (AI 171) and another 33 persons on ground including some medical students, were killed when the London-bound aircraft crashed into the BJP Medical College in the Ahmedabad civil hospital in Meghaninagar area and burst into flames, moments after it took off from the Sardar Vallabhbhai Patel International Airport.
The term ‘black box’ refers to a set of two devices that records conversations between the pilots and with Air Traffic Control, as well as flight data parameters like altitude, heading, and airspeed that help to ascertain the causes of a plane crash even when various theories are floating about the possible causes. All the information required by investigators to establish how and why a plane crashed is stored in the CVR and FDR.
There are some of the key questions CVR data should be able to answer. Last week the Civil Aviation Ministry said a distress call had been broadcast seconds before impact. ‘Mayday, mayday…’ was what Captain Sumeet aSabharwal reportedly told Ahmedabad ATC. There are, however, reports that Captain Sabharwal had also flagged the loss of power and thrust.
CVR data should reveal if he did, indeed, also say ‘… no power… no thrust…’, which will be a key piece of evidence pushing investigators to focus on the engine as the cause for the crash.
CVR data will pinpoint the exact millisecond Captain Sabharwal sent his ‘mayday’ message, which will establish just how much time First Officer Clive Kunder and he had to try and rescue the plane and the 240 other people on board, including 10 other crew members.
Knowing when the ‘mayday’ call was sent will also allow investigators to work out when the problem (that caused the crash) manifested, i.e., was it present before take-off and did the pilots not notice it or did it happen after lift-off, perhaps prompted by a system failure?
Again, the CVR will also tell investigators exactly what Captain Sabharwal and First Officer Kunder said to each other and the ATC. Of course, the ATC personnel will have already been debriefed, but they may not remember everything that was said or even the tone in which it was said, which can provide clues.
And they will not know what the pilot and first officer said to each other in the plane. The CVR records all of this, as well as ambient noise from the cockpit, including that of the engine. Crucially, ambient noise will include alarms that may have blared in the cockpit in the seconds before the crash, vibration feedback from the controllers, etc. It will also let them know how the pilots responded to these alerts.
The parallel to the CVR data, investigators will also have access to key flight parameters that will allow them to re-create, in real-time the flight path of the doomed Air India plane.
