The crash occurred during a rescue operation to evacuate two people from the mountain for medical reasons. The pilot, a guide, and a doctor were also killed, according to AFP.
An investigation into the accident has been opened.
Kilimanjaro is a popular tourist destination. The mountain is surrounded by a national park and visitors flock there both to go on safari and to climb Uhuru Peak on Kilimanjaro, Africa's highest natural point, at 5,895 meters above sea level.
