Why the tabletop Kozhikode runway amplified landing risk

A commercial pilot with over 15,000 hours of flying explains

Negotiating a tabletop runway, laid over the levelled surface of a hill, is tricky even in the best of weather. But the heavy downpour that enveloped the entire Kozhikode International Airport on Friday evening made landing extremely tough. Typical of tabletop accidents, the flight overshot the runway and dropped.

Since the aircraft did not catch fire on impact after falling 35 m into the valley down below, the toll did not cross 19. But in the aviation world, tabletop runway spelled disaster after the 2010 Mangaluru airport accident that killed 158 passengers.

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On May 22, 2010, the Boeing 737 Air India Express flight from Dubai had overshot the runway’s threshold touchdown area, failed to stop and rolled down the steep hillside. Besides the Kozhikode and Mangaluru airports, India has a third tabletop runway, attached to the Lengpui airport in Mizoram.

The bad weather amplified the challenges posed by the Kozhikode airport’s structure. As a commercial pilot with over 15,000 hours of flying explained to DH, flights landing on tabletop runways have to deal with valley winds (from both ends of the runway) and the tailwinds.

The valley wind rises upwards and pushes up an approaching aeroplane, forcing the touchdown to be longer than intended. “The aircraft ends up eating up the runway length with reduced braking. Unlike headwind from the front that helps slow down the aircraft, the tailwind pushes it from behind.”

Kozhikode plane crash: Pilot had aborted first attempt, reversed direction of landing in the second

Despite these challenges, the pilot has to keep the aeroplane’s nose down, maintaining a three-degree angle. This makes it even tougher to reduce speed. “So, the braking action, aircraft weight, approach path gradient, weather are all contributory factors,” the pilot said, preferring anonymity.

Landing accuracy is extremely critical on a tabletop runway. There is hardly any margin of error for the pilot. Besides, he also has to deal with ‘optical illusion,’ where the runway appears to continue despite the drop ahead.

But, operated by a veteran Indian Air Force (IAF) pilot, the flight had no issues on this front. Still, questions are now being raised why the flight was not diverted, and what conversation transpired between the pilots and the Air Traffic Control (ATC).

Aviation regulations dictate that flight diversion to a nearby airport is the only option after two failed landing attempts. Kozhikode ATC sources had told DH that the pilot had aborted the first attempt and had landed from the reverse direction. The Director General Civil Aviation (DGCA) is expected to probe deeper.

Located atop a plateau, the Kozhikode airport has had issues with its tabletop structure. On both ends of the runway, the landscape slopes into a gorge. Safety issues had forced many international airlines to halt their wide-bodied aircraft from flying in.