Nearly five months after an Air India Express Boeing aircraft crashed during landing at Mangalore airport killing 158 people on board, flight details contained in the black box have revealed that the pilot-in-command was asleep for an hour and 50 minutes when the plane cruised towards its destination.
An analysis of the cockpit voice recorder (CVR) -- which contains conversation between two pilots, radio communication between the cockpit crew and others (including conversation with air traffic control personnel) and Digital Flight Data Recorder (DFDR) -- was presented before the Court of Inquiry (CoI) headed by Air Marshal (Retd) B N Gokhale.
The Directorate-General of Civil Aviation (DGCA), which presented the details to the CoI, had sent the CVR and the DFDR to the United States for data retrieval since they were heavily damaged, though the memory chips remained intact.
In the CoI, officials from Boeing, the manufacturer of the aircraft, and GE, which was involved in decoding the black box, presented their findings.
Only excerpts of the black box data were released on Wednesday and a detailed report will be submitted to the Centre along with the CoI findings by the end of this month.
The startling details culled from the CVR and the DFDR have now established that pilot error, compounded by others factors like sleeping, caused the crash.
The cockpit transcripts and coded DFDR information were released to silence persistent speculation that reasons other than pilot error might have contributed to the doom of the aircraft and the 152 passengers and six crew members.
The analysis of the CVR revealed that there was sound nasal snoring and heavy breathing for nearly two hours, indicating that one of the two pilots-in all likelihood Serbian national Captain Zslatko Glucika, 55-had fallen asleep on his seat on the 200-minute flight of IX-812 that originated in Dubai (local time 1:10 am) on May 22.
What corroborates the pilot error as the principal reason behind the crash is the long silence in the cockpit—for as long as 110 minutes-indicating that Glucika, who was believed to have about 2,000 flying hours’ experience, had dozed off ahead of landing. Captain H S Ahluwalia, 40, from Mumbai, was the co-pilot of the ill-fated aircraft.
When it was time for flight IX-812 to land, it was too late. The black box details have established that the aircraft started descent for landing when it was flying at an altitude of 4,400 feet against the normal height of 2,000 feet. Besides, the flight touched down at the 4,638 feet mark on the middle of Mangalore’s ‘table-top’ runway which has a maximum length of 8,038 feet.
According to civil aviation regulations, normal touchdown mark for passenger aircraft is 1,000 feet. This strongly indicates that Glucika not only reacted late and overshot the runway, but certain standard operating procedures were not followed during landing.
DHNS reported on August 19 the pilots’ last-minute conversation in which Capt Ahluwalia desperately cautioned Glucika to abort landing and “go around”, meaning that the pilot should not attempt a landing and instead try to fly without touching down.
The co-pilot is heard on the audio telling Glucika “we don’t have enough runway left”. Capt Ahluwalia’s last word to his commanding pilot was “control” and then the aircraft fell on to a steep slope before exploding into a ball of fire.
According to the decoded information from the black box, the aircraft was not on its glide path while landing. As suspected earlier, the Boeing 737-800 aircraft was flying at an unusually high speed of 139 knots during landing. In the course of the inquiry and inspection of the aircraft’s remains it was found that the plane’s landing gear was found in the takeoff position, suggesting that the pilot tried a “go around.”
“Despite the high speed and landing in the middle of the runway, had the pilot tried to stop the aircraft instead of taking off after making touch down, it would have stopped at least at the end of the run way averting the disaster,” a Boeing official said. In support of the evidence that the pilot tried a “go around,” the DFDR shows that Glucika activated the takeoff gear and that the engine was in powered to high speed. “During normal touch down the engine speed is always low”, the official said.
“The main reason for the accident was that the pilot(s) tried to take off when just 800 feet of the runway was left. It was a wrong judgment while attempting a takeoff,” he said.
The decoding of the black box also shows that the GPS (ground proximity warning system) precision approach and landing system of the aircraft had given several warnings indicating that it was taking a wrong glide path. The CVR records show that both pilots had discussed that the aircraft was following a wrong glide path.
Early on May 22, the weather was fine for landing and visibility 6 km. The runway was dry and clearance had been given for landing under the Instrument Landing System. According to Boeing, the runway length for a 737-800 type aircraft during landing should be 7,500 feet.
(This article is quoted from the Deccan Herald News Service although several versions of the story have been sent to media taking credit for it)