The aircraft came down near the Long Mountain at 12.41pm. The accident scene is near to the Mid Wales Airport in Welshpool. Emergency services were called after reports of an incident involving a light aircraft.
Early reports suggested the plane was a seven-seater, although it is not known how many people were on board.
Wales Air Ambulance spokeswoman Christina Rankin-Moore said: “We can confirm that the Welsh Air Ambulance attended the scene of an aircraft crash in the Welshpool airport area.
“Two patients were pronounced dead at the scene. The incident is now being handled by Dyfed-Powys Police.”
Dyfed Powys Police spokeswoman Sian George said the investigation centred around the Leighton area of Welshpool.
She said: “Police are currently dealing with an incident involved a small aircraft in the Leighton area of Welshpool.
“Further details will be released on the incident when information becomes available.”
Unconfirmed reports say the plane came down near the hamlet of Hope.
Witnesses reported a seven-seater aircraft was involved in the crash.
Graeme Mulvey, headteacher of Leighton C.P School, said staff saw police and ambulances racing up the mountain but was not aware of what had happened.
Nobody from Mid Wales Airport would comment this afternoon. The airport is two miles south of Welshpool. It was developed from a grass airstrip in 1990 to act as a base for companies operating aircraft in the area.
Earlier this week two people escaped injury after their helicopter crashing into the side of a mountain next to the Lake Vyrnwy Hotel.
The helicopter was heading for the landing pad at the Lake Vyrnwy Hotel but crashed and caught fire about 100 yards away. Staff from the hotel were quickly on the scene and helped free the couple. The 30-year-old man and the 32-year-old woman from the Cotswolds escaped serious injury.