The Twin Otter Summit Air plane was taking off from Tenzing-Hillary Airport in Lukla when it collided with the Manang Air helicopter this morning.
The dead include one of the pilots of the plane and two police officers who were near the parked helicopter.
Police spokesman Uttam Raj Subedi said: “The co-pilot and a policeman died at the crash site.
“Another police officer died in a hospital in Kathmandu.”
The police were tourist cops sent to the area and the dead and wounded are all Nepalese.
Four of the passengers and a flight attendant on board the plane were safe, civil administrator Narendra Kumar Rama, said.
The other pilot from the plane and the helicopter pilot are among the injured – they were airlifted to Kathmandu.
Reports suggest the plane skidded off the runway to the right and hit the helicopter as it landed from Kathmandu.
The helicopter was cut in two and three others were damaged.
Both airlines are private companies serving locals and tourists in the remote areas of Nepal.
Tenzing-Hillary Airport is known as the gateway to Everest and is regarded the world’s most dangerous because of its difficult approach and short runway.
There are about 35 flights and 100 helicopter ferries a day from the airport.
Hundreds of foreign climbers head to Mount Everest in April during the commercial expedition season, which lasts until May.
The airport is named after two men who were first to climb the 8848-metre peak.
Last month, seven people, including Nepal’s tourism minister were killed in a helicopter crash in eastern Nepal.