NEW YORK • It was supposed to be a routine refuelling stop in Zimbabwe by an American-owned cargo plane travelling to South Africa from Germany.

Then airport officials noticed blood spattered on the fuselage and found a corpse inside, plus a small fortune in South African cash.

They impounded the aircraft after Sunday's discovery and began an investigation into how and where the apparent stowaway got on board.

The Zimbabwe newspaper, the Herald, reported claims that the unidentified man had apparently sneaked into the landing gear opening and was crushed when the gear retracted after take-off.

Photos on social media suggest that the unidentified man's arm was severed, causing blood to splatter onto the fuselage and arousing the suspicion of the ground crew when the flight landed.

The Herald said the crew members - two Americans, a South African and a Pakistani - had not been aware of the corpse.

Florida-based Western Global Airlines, which confirmed on Monday that it owned the MD11 cargo plane, said in a statement that the corpse was suspected to have been a stowaway "who may have entered the airplane during a previous stop".

The Herald said the plane had been "stashed with millions of rands". One million rand is equivalent to about US$62,500 (S$87,600).

Western Global said the cash was a shipment for the South African Reserve Bank.

South Africa's ambassador to Zimbabwe Vusi Mavimbela said on Monday that a few officials from the South African central bank had been on board the flight.

"Unfortunately, there was a stowaway that was found on the plane and (Zimbabwe) authorities are trying to get to the bottom of the issue," he said.

"Where did the person get in there? When and how? Because the crew and the Reserve Bank authorities who were there accompanying the cargo were not aware," he said.

Western Global Airlines, which is privately owned, advertises itself as one of the world's fastest-growing low-cost air cargo companies, with clients around the world. It flew dozens of humanitarian missions to West Africa during the height of the Ebola crisis.

REUTERS, NEW YORK TIMES