An important tourist connection goes from Tribhuvan International Airport (VNKT) in Kathmandu, at 4,390 ft, to Tenzing-Hillary Airport (VNLK) in Lukla, at 9,334 ft. The mountains around Lukla quickly raise from south to north. Right around Lukla the ridges rise to about 15,000 ft, but the aircraft does not have to fly over these, since decent approach is only possible through the valley from the south and the ridges are somewhat lower further south. So does anybody know what is actual typical cruise altitude in that area?
I am sure I have no knowledge for reading charts but en-route charts for Nepal indicate something like F170 which I translate to FL170 or 17,000 ft. Pls correct me if I misunderstand it.
Here is the source
You need to be between 13k - 9.1k ft for the Kathmandu to Lukla flight. This source would probably answer your question.