Why is landing at Kathmandu Airport so difficult?

An article published on Flightradar24.com written by Chris Lomas, 01 Sept 2024

Operating aircraft at Kathmandu’s Tribhuvan International Airport (KTM) presents a unique set of challenges that make it one of the most difficult airports in the world for pilots. It’s no wonder that the area is one of the most frequently tracked areas on Flightradar24. The airport’s location, high altitude, unpredictable weather, and infrastructure limitations contribute to the operational complexities. Let’s take a look at some of those factors in more detail.

1. Geographical Location and Topography

Kathmandu Airport is nestled in a valley surrounded by the towering peaks of the Himalayas. The airport sits at an elevation of 4,390 feet above sea level, and its approach path is constrained by mountainous terrain. Pilots must navigate through narrow passes, which leaves little room for error. The steep descent required to land adds another layer of difficulty, demanding precise control and extensive experience.

2. High Altitude

The high elevation of the airport at KTM reduces overall engine performance, affects aircraft handling, and necessitates longer takeoff and landing distances. This is one of the reasons KTM features a long 3,074 meter / 10,085 foot runway. The thinner air at high altitudes means that aircraft engines produce less thrust, and lift is harder to generate, making both takeoffs and landings more challenging. These factors require pilots to carefully calculate their approach speeds and landing distances, taking into account the reduced performance. Turboprop and jet aircraft behave differently in such circumstances. Turboprop engines are generally designed to operate efficiently across a broader range of temperatures and altitudes. They can maintain better performance in hot and high conditions because the power produced by the turbine drives the propeller directly, rather than relying solely on jet exhaust for thrust.

Turboprops vs jets – what’s the difference?

It is interesting to note that, as the region has some of the highest minimum safe altitudes (MSA’s) in the world, the area presents additional challenges in the event of experiencing pressurization failures. The immediate actions in such an event are to don oxygen masks and descend to 10,000 feet or the MSA (whichever is lower), as passengers can safely breathe with the level of oxygen at that height. Due to the height of the terrain in the region being often in excess of 15,000 feet, it would be impossible to do so. This is why Nepal generally sees very low levels of overflight traffic and forms one of our gaps in the map.

3. Unpredictable Weather

Weather conditions in Kathmandu can change rapidly and unpredictably. The airport often experiences poor visibility due to fog, particularly during the winter months. Wind patterns can also shift suddenly, leading to turbulence and crosswinds that make landing even more hazardous. Additionally, monsoon rains can cause water accumulation on the runway, increasing the risk of hydroplaning.

During more extreme weather, aircraft are frequently required to fly holding patterns to the south of the airport to wait for weather conditions to improve to within limits. This area is chosen due to the relatively low terrain compared to the mountainous conditions closer to the airport.

What’s the hold up – how and why do aircraft hold at airports?

4. Limited Infrastructure

Tribhuvan International Airport is the only international airport in Nepal and has limited infrastructure to handle the increasing volume of air traffic. The single runway, which must accommodate both takeoffs and landings, can often become congested, leading to delays. The airport does feature a range of instrument approaches to support arriving aircraft. Currently available are RNP, LOC DME and VOR approaches. These approaches feature strict and complex missed approach procedures that keep aircraft clear of the surrounding terrain in the event of a go around. 

How do aircraft land in low visibility?

5. Human Factors

Operating in such an environment demands highly skilled and experienced pilots. However, even seasoned pilots face stress due to the combination of high altitude, challenging approaches, and unpredictable weather, which can affect decision-making under pressure.

A unique mix of geographical, meteorological, and infrastructural factors makes Kathmandu Airport one of the most challenging airports in the world to operate to, requiring exceptional skill, training, and vigilance of crews and air traffic controllers to ensure safe operations.

Cover photo: Karib Ahmed, JetPhotos.