The engine malfunction comes against the backdrop of two high-profile jetliner accidents this year.

An Airbus A350 passenger plane operated by Japan Airlines collided with a Coast Guard aircraft in Tokyo, killing five crew members on Jan. 2.

 

A few days later, a Boeing 737 MAX 9 jet made an emergency landing following a cabin panel blowout, which prompted the FAA to temporarily grounded 171 jets for safety checks.

The Atlas Air Flight 5Y095 was on its way to San Juan, Puerto Rico from Miami International Airport on late Thursday evening.

The pilot made a Mayday call around 0333 GMT to report an engine fire and requested to return back to the airport, according to multi-channel recordings of conversations between the air traffic control and the plane available on liveatc.net.

"We have a engine fire," one of the plane crew said, disclosing that there were five people on board.

The crew member said the incident involved engine number two and it occurred "on the climb out" of the airport.

Atlas Air, whose customers include parcel delivery giants DHL and FedEx, went private last year when it was bought by a group led by private equity Apollo Global Management (APO.N)

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Once known as the "Queen of the Skies", the Boeing 747 revolutionized air travel and was the world's first twin-aisle wide-body jet.

But technological advances made it possible for dual-engine jets to replicate its range and capacity at lower cost and Boeing decided in July 2020 to end 747 production.

A freighter version of the last commercial Boeing jumbo was delivered to Atlas Air last year.