Data from tracking website Flightradar24.com showed the aircraft was 17 years old. The aircraft descended to an airport altitude of 4,400 feet and then ascended up to 6,600 feet before crashing about two minutes later, the website said.
Mountainous Nepal is notorious for air accidents and small aircraft often run into trouble at provincial airstrips.
A Thai Airways flight from Bangkok crashed while trying to land in Kathmandu in 1992 killing all on board.
US-Bangla Airlines is a unit of the US-Bangla Group, a US Bangladeshi joint venture company.