Onset of winter leads to flight delays


With domestic and international flights now near pre-Covid levels, and the onset of winter means Kathmandu airport is once more living up to its reputation for congestion and flight delays.

In the past week, heavy industrial pollution and smoke haze from crop fires in India have increased air pollution and reduced visibility in Kathmandu Valley. Combined with the capital’s increasing vehicular emissions and winter inversion, the pollution is trapped at ground level reducing visibility at the airport.

The direct impact of this is on flights in and out of Kathmandu, which with its single runway was already operating at maximum capacity even before the pandemic.

“Passengers arrive at the airport at the stipulated time, but because of the congestion caused by poor visibility, they have to wait for hours because of delayed flights, it is not within the control of the operators,” says Dipendra Karna of Buddha Air, Nepal’s largest domestic airline.

Karna pinpoints the main reason for delays as air traffic congestion caused by visibility below minimum at Kathmandu airport, and because under Instrument Flying Rules (IFR) the runway can take only one landing every 7 minutes.

Under IFR conditions, flights can only land from the south, and the taxiway does not extend to the end of the runway, leading to added delays also for departures. Both international and domestic flights have to hold sometimes for hours to wait for their turn to land or takeoff at Kathmandu, burning expensive fuel.

Many international flights in winter end up diverting to Lucknow, Kolkata or Delhi because of the lack of alternative airports for big jets in Nepal.  This situation could improve with the new Pokhara and Lumbini airports coming into operation next year.

As winter sets in, airports in the Tarai like Biratnagar, Bhairawa and Nepalganj also face visibility issues because of the Indo-Gangetic smog, which has been getting worse every year. Delays in the mornings then snowball into longer delays by afternoon, and cancellations of many flights. Some airports like Pokhara and remote area airfields also have the additional limitation of not being able to operate at night.

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“For safety reasons, even if the destination airport is clear, a flight may not be able to operate because alternate airports do not have enough visibility,” Karna explains. “For example, it is not enough for Biratnagar to be open, nearby Janakpur and Rajbiraj also need to have enough visibility before a flight can take off from Kathmandu.” 

The situation has improved slightly in the past few years after night landing facilities have been installed at major airports in the Tarai allowing flights delayed during the day to operate later.

As Kathmandu’s pollution gets worse, and the airport now enveloped on all sides by urban sprawl, the heavy traffic on the roads adds to the pollution and bad visibility, leading in turn to congestion in the air.

“Flight safety is paramount for airlines, and the Civil Aviation Authority of Nepal also has a responsibility in upgrading navaids and streamlining air traffic control,” says Karna. “The delays are not only a hassle for passengers, crew and airline staff but adds to the carrier’s fuel costs, piling an extra economic burden on the state.”

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