THIRUVANANTHAPURAM: The Air India Express plane involved in the accident at the Kozhikode airport on Friday night that claimed 18 lives approached the runway at a speed higher than what is ideal for a safe touchdown, sources at the airport revealed.
Also, it is learnt that the aircraft touched down on the runway well beyond the threshold mark, making it a risky landing.
Besides, it is suspected that the reverse thrust mode used to reduce the speed after landing probably didn’t work, which could indicate a technical fault.
“Normally, aircraft approach the runway at a speed range of 220-240kmph (120-130 knots). But this plane descended on the runway at over 300kmph,” said a reliable source in the Airport Authority of India.
Further, the aircraft touched down on the 2,860-metre runway (which includes the 240-metre Runway End Safety Area) at the 1,300-metre point.
The Boeing 737 with 190 on board skidded and fell off the edge of the table-top runway while landing in bad weather.
The Aircraft Accident Investigation Bureau and the Directorate General of Civil Aviation have launched an investigation into the accident.
An inspection of the accident site also raised suspicion whether the aircraft engine had really worked in reverse thrust — a process of temporarily diverting the engine’s thrust against the forward travel to provide deceleration. According to experts, even aircraft that touchdown beyond the threshold mark can be effectively stopped if the engine is in the reverse thrust mode.After landing, the plane crossed Runway End Safety Area and broke the instrument landing system lights.
The officials who inspected the site told Express the splinters of the landing system lights were strewn on the tarmac.
“If the aircraft was in the reverse thrust mode, the splinters would have been lying on the front side,” one of them said.
“Further, around 90 metres of the sand-filled portion ahead of the runway remained almost intact, showing no signs of reverse thrust,” said an official.
The official, however, said it’s hard to believe that a senior pilot in command, who used to train Air India Express pilots, did not put the plane in reverse thrust mode in a distress condition.
“Maybe something beyond one’s judgment or imagination would have happened. We have to wait till data from the cockpit voice recorder (CVR) and flight data recorder (black box) are decoded, which can give a clear idea about what happened in the last minutes,” the official said.
Meanwhile, airport sources told Express that the runway surface tailwind during the time of landing was 8 knots, while a Boeing 737 can withstand a tailwind of up to 15 knots.The sources also confirmed that when the pilot aborted the first attempt to land on Runway 28, he cited heavy wind as the reason.
Later, he approached Runway 10 after the takeoff of a Delhi aircraft from the same runway. No distress signal was sent to the air traffic control unit of the airport from the cockpit even after landing, sources said.