The airstrip at Lukla, at 2,846 m in the Dudh Kosi valley, is the front door to the Everest region. Most trekkers heading for Namche Bazaar, Gokyo or Everest Base Camp arrive by a flight that takes less than half an hour, and most of them, sooner or later, spend at least one morning sitting in a departure hall watching the cloud. Understanding how the flights work, why they stop and how to plan around the uncertainty is as much a part of the trek as the walking. This is what we have learned over many seasons of arriving and, more stressfully, leaving.
Why the runway is unusual
The Lukla runway is about 527 m long, which is a fraction of what a normal airliner needs, and it slopes at close to 12 percent. Aircraft land uphill toward a mountain wall, which slows them, and take off downhill toward a drop into the valley, which speeds them up. There is no room to go around once a landing is committed. Only small turboprop aircraft with 15 to 19 seats and helicopters can use it, and only under visual flight rules: pilots must be able to see the runway and the terrain around it. Instruments cannot substitute for a clear view, and this single fact explains almost every delay.
Weather, mornings and the daily window
Mountain weather in the Khumbu follows a daily cycle. Mornings are usually clear; by late morning cloud builds in the valleys and by early afternoon the airstrip is often wrapped in it. Flights are therefore scheduled from first light, and the first two or three hours of the day carry most of the traffic. If cloud sits at either end of the route, in Kathmandu, at Lukla or over the ridges between, nothing moves. The pattern is worst in the monsoon months from June to September, when days can pass without a flight, and best in the post-monsoon window from October to November and the spring season from March to May. Even in the best months, a backlog of a day or two is common after any spell of bad weather.
Wind matters as well. The valley wind at Lukla rises through the morning and can exceed the limits for a safe landing on a runway that offers no second attempt. A perfectly blue sky is no guarantee of a flight.
Kathmandu or Ramechhap
During the two peak seasons, when hundreds of flights a week overwhelm the capital’s single-runway international airport, the authorities move Lukla flights to Manthali airport in Ramechhap district, about 130 km east of Kathmandu. The flight from there is only 15 to 20 minutes, but reaching it means a road journey of four to five hours, and because the flights leave at dawn that journey typically starts at midnight or means a night in a basic guesthouse near the airfield. Outside the peak seasons, and on some dates within them, flights operate from Kathmandu directly. The arrangement changes from year to year, so the departure point should be checked shortly before travel rather than assumed from a previous trip.
Whichever airport is used, the logistics are the same: check in early with a duffel and day pack that together weigh about 15 kg, hold on to the boarding card, and be ready to board within minutes of a call, because the pilots are trying to fit as many rotations as possible into a shrinking window.
Buffer days are not optional
The single most important planning decision for an Everest region trek is to leave at least two, and preferably three, spare days between the planned return to Lukla and the international flight home. A one-day delay at the end of a trek is normal. A two-day delay is unremarkable. Longer delays happen every season and are the reason the lodges at Lukla stay full. If the buffer is not needed, it becomes a day in a city, a bath and a proper meal, none of which is a hardship.
The buffer also protects the walk itself. Someone who knows they must fly out on a particular day is tempted to skip an acclimatisation night, push through a headache or cross a high pass in bad weather. Spare days at the end of the itinerary remove that pressure, and remove the temptation to do something dangerous for the sake of a booking.
When the flights stop
When a backlog builds, the queue works roughly in order of the original booking date, with each day’s stranded passengers rolled onto the next morning. Staying near the airstrip and checking in early each day matters, because seats on a clearing morning fill fast. Helicopters keep flying in conditions that ground fixed-wing aircraft, and charter seats are sold per person when the wait grows, at several times the price of the flight. For a group of five, sharing a helicopter can be a reasonable way out; for one person, it is expensive, and travel insurance rarely covers weather delays of this kind, so read the policy before relying on it.
There is also the ground. From Lukla, a walk of two to three days down the valley reaches Phaplu and Salleri, from where a jeep or bus takes the better part of a day to reach Kathmandu. Phaplu has its own small airstrip, which sits lower and is less affected by cloud. Going the other way, the old approach on foot from Jiri or from the roadhead near Salleri takes five to seven days and adds a beautiful and quiet section of the Solu region to the trek. Building this in at the start turns a risk into a feature, and it also delivers you to Lukla already partly acclimatised.
Our habits
We book the earliest flight available, since the first rotations are the ones that get away. We carry a spare day’s worth of food, cash and patience. We arrange the trek so that the last night on the trail is at Lukla itself, not a village three hours away. We keep the return international ticket on a fare that can be changed, and we keep the hotel in the city informed. And we treat the airline staff at Lukla with the courtesy that people who are shouted at every day of the season deserve. None of this removes the uncertainty. It just means that when the cloud comes down, it is a delay rather than a crisis.