There are only a handful of airlines operating scheduled flights to Kathmandu (KTM elevation 4390 feet/ 1338 meters), situated in a valley amidst towering mountains on the flanks and the formidable Himalayas blocking escape beyond.
I had the opportunity to fly as a captain for our airline to Tribhuvan International Airport five times at least, and every time it was breathtaking experience. In the summer with the Monsoon season affecting the Indian subcontinent, the task gets more complicated as there is severe weather to contend, along with the Indian Air Traffic Control, who are not always in tune with descent requirements of high speed jet aircraft.
So, inevitably, we ended up at the Sierra radio beacon, some eighteen nautical miles from the airport for an instrument let down, i.e., you are descending in a racetrack holding pattern amidst terrain and thunderclouds you better not think about at the time. After lining up with the VOR (VHF Navigation Receiver) inbound radial (course) leading to final approach, it is a step descent. In other words the aircraft cannot go lower in that particular segment allocated by distance to go on the area instrument arrival chart.
Our airline lost an Airbus A-300 here in descent profile in clouds on approach when the crew misjudged the safe height and hit the crest of a mountain. Some of the pilots have refused to fly to this airport citing legal requirements to be met in case of engine failure on takeoff. For any aircraft it is a challenging environment, more so with the heavier ones.