The Air India Express plane, which was repatriating Indians stranded in Dubai due to the coronavirus pandemic, overshot the runway of the Calicut International Airport in heavy rain near the southern city of Kozhikode on Friday.
The plane skidded off the runway, plunging into a valley and crashing nose-first into the ground, officials said.
What is a table-top runway?
* Table-top runways are often constructed by excavating the peaks of hills to create what is known as a “table-top”.
* Such runways have steep drops at one or both ends, increasing the possibility of injuries and fatalities if pilots under or overshoot their approach, either through human error or mechanical failure.
* This type of runway creates an optical illusion which requires a very precise approach by the pilot.
* They are most commonly found in mountainous areas where flat land is scarce, or in low-lying areas like Kozhikode where space is at a premium or there is fear of waterlogging at ground level. Other examples include the international airport of Nepal in mountainous Kathmandu.
Kozhikode’s table-top runway
* The Kozhikode airport has a table-top runway which is operated by the Airports Authority of India.
* The table-top runway at Kozhikode is around 2,700 metres (8,858 feet) long, shorter than the 4,430 metres (14,534 feet) runway in New Delhi, though it is long enough for narrowbody aircraft like the Boeing-737 to land.
Expert warned in 2011
* The airport is unsafe and landing should not be allowed here, especially during wet conditions, Captain Mohan Ranganathan, a member of a safety advisory committee, had warned more than nine years ago.
* It is a tabletop runway with a downslope. The buffer zone at the end of the runway is inadequate, he said. Given the topography, he pointed out, the airport should have a buffer of 240 metres at the end of the runway, but it has only 90 metres (which the DGCA had approved).
* Moreover, the space on either side of the runway is only 75 metres instead of the mandatory 100 metres.
India’s table-top runways
* India has three table-top runways from where flights operate.
* These include Calicut International Airport, Mangalore International Airport, Karnataka and Lengpui Airport, Mizoram.
* The plane crash at Kozhikode is the second such incident which involved a table-top runway, the first being at the Mangalore airport in 2010.
* The Kozhikode airport is located on a hill with limited space at the end of the runway, and several international airlines had stopped flying bigger aircraft including Boeing 777 and Airbus SE A330 jets into the city due to safety issues.
* The runway at Kozhikode, where the latest crash took place, doesn’t have an adequate safety mechanism, a member of the aviation regulator’s civil aviation safety advisory council had written in a letter to the government in 2011.
* A ground arrestor system, similar to those maintained at Air Force bases, should be installed at table top airports to bring any skidding aircraft to a halt, an investigation report into the 2010 crash of another Air India Express jet recommended.
Mangalore’s table-top runway crash
* Friday’s crash was India’s worst passenger aircraft accident in a decade, that also involved a table-top runway.
* In May 2010, an Air India flight landing at Mangalore airport overshot the table-top runway there, falling down a hillside and bursting into flames.
* Of the 166 people on board, only eight survived. The inquest into the crash later blamed pilot error.
(With inputs from agencies)