A plane that left Porto bound for Angola was forced to make an emergency landing only 30 minutes after take-off when it became apparent one of the ground crew was trapped in the hold.

The TAAG Angola Airlines Boeing 777-300 left the Portuguese city bound for the southern African country on Saturday, but was diverted to Lisbon, around 170 miles away, when staff at Porto realised a member of its crew was missing.

The aircraft had reached 35,000 feet when it had to turn around Credit: FlightRadar24.com

After Flight DT6544 made a sudden turnaround and rapid descent to Lisbon Airport, the man was discovered locked in the cargo hold and suffering from hypothermia. According to data from Flight Radar 24, the aircraft had reached nearly 35,000 feet, where the temperature outside drops to -55C, before being forced to turn around.

The man, who is recovering in hospital, was loading a box of passengers’ pets when he fell and became unconscious, the Aviation Herald reported. The plane then departed and it was not until 40 minutes after the aircraft left the gate that staff noticed his absence. The industry website said the man was “securing two animals”.

Lisbon is about 170 miles south of Porto Credit: Copyright: Roberta Patat/Photographer: Roberta Patat

An investigation into the incident has begun and Telegraph Travel had contacted Porto Airport and Angola Airlines for comment.

The baggage handler is not the first to have survived a flight in the cargo hold. Roberto Viza Egües managed to flee Cuba on August 12, 2000, after hiding in an Air France cargo container at Havana Airport. He arrived in Paris the following day, suffering from exposure, but otherwise unharmed. His application for asylum was denied and he was eventually deported back to Cuba.

Last year a stowaway survived a one-hour flight hiding in the wheel cavity of a Garuda Indonesia plane. He was discovered wobbling and bleeding on the tarmac by ground crew in Jakarta. “He looked lacking of oxygen. His fingers turned blue, his left ear was bleeding” said Pesman Pujabroto, a Garuda Indonesia spokesperson.

Other flights have had the misfortune of having to divert for far less serious reasons. In March a United Airlines aircraft that left New Jersey bound for Texas had to turn around because of concerns about a “strong” odour.

In 2012, an American Airlines flight from Dallas-Fort Worth to Chicago had to return to the gate after a flight attendant made “inflammatory” remarks over the tannoy system just before take-off.