Kozhikode plane crash brings safety of ‘table top’ runways into question

Ashwini Phadnis New Delhi | Updated on August 12, 2020

While landing at a table top runway, pilot’s depth perception can go awry   -  PTI

The Air India Express crash in Kozhikode on August 7 has brought focus back on table top runways and their safety. India has five table top runways including the one at Kozhikode. In 2010, an accident at another table top runway, in Mangaluru over 150 people died. The other table top runways are at Pakyong (Sikkim), Shimla and Lengpui (Aizwal).

However, these two have been the only fatal accidents at table top runways in the recent past.

Sources in Airports Authority of India, which manages most of the airports in India, including the one at Kozhikode, say that Standard Operating Procedures for operating in to Kozhikode and other airports are in place adding that Kozhikode has Runway End Safety Area (RESA) as recommended by International Civil Aviation Organisation on both sides of the runway.

They further point out that an accident is as a result of a variety of contributory factors like the heavy rain on the day of the crash and strong winds adding that the airport had handled several million passengers and several thousand international flights before this incident occurred.

Pilots’ concern

However, pilots point to the challenges of landing at a table top runway. As the name suggest a table top runway is built on an elevated surface with a drop at both ends. This means that landing on one is very different from landing in an airport in the plains for example in Delhi and Mumbai.

“The danger is quite obvious. You need to ensure that you touch down within the prescribed zone which is defined as the first one-third of the runway or 3,000 feet, whichever is lesser,” says a senior pilot with a private airline.

He adds that if the aircraft touches down beyond the ‘touchdown zone’ there is the danger of the pilot not being able to stop within the confines of the runway. “Unlike a runway on the plains, you then run the risk of dropping off the edge and into the gorge beyond with obviously disastrous results,” he adds.

Preliminary reports suggest that this is what happened to the Air India Express flight at Kozhikode as it touched down after the touchdown zone.

Another issue with landing at a table top runway is that the pilot’s depth perception can go awry. “The best way to deal with this is by ensuring that you follow the Standard Operating Procedures strictly, be situationally aware at all times, ensure that your approach is stabilised and, most importantly, do not hesitate to go around in case you are not situated to do a safe landing,” says a pilot. The pilot of the Air India Express flight did two go-arounds before landing for the third time when the plane crashed.

Pilots BusinessLine spoke to said there are three important things for them to consider while landing at any airport -- the runway, a portion called stop way and then the portion called clearway--- the stop way is supposed to have some kind of deceleration surface that is strong enough to hold an aircraft while the clearway is supposed to have no object above a particular height as this is also used as the take-off path by an aircraft.

However, table top runways are not the only ones which are difficult to land in. Pilots also talk about other airports like the ones in Leh and Patna which are not table top airports but where it is equally challenging to land.

Other hazards

The runway at Leh is at an elevation of over 10,000 feet and it is situated in a deep valley surrounded by high mountains.

“Flights here are totally visual. You have to eyeball a plane and land. You eyeball the landing. The height of the runway, surrounding terrain and very low density means that the performance of the plane goes down a lot,” says a pilot who has flown to both Kozhikode and Leh airports.

Patna airport not only is it a short runway but the strip is also narrower than usual. However, these are challenges which pilots are trained to handle.

What they have no control over is how infrastructure development is not keeping pace with increasing demand in smaller cities and towns. Traffic to smaller airports is increasing but there are very few changes in the infrastructure at these airports to keep up with this increasing demand. For example, Kozhikode airport handled 2.37 million international passengers in April-January 2019-20 as against 2.29 million handled during the same period previously or an increase of 3.5 per cent. Similarly, the number of international aircraft movements at the airport saw a 3 per cent increase to 16,219 international aircraft movements.

Published on August 12, 2020

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