The Boeing 777-300ER was travelling from Hong Kong to Los Angeles when the emergency took place on Wednesday. All 276 passengers and 18 crew members escaped unscathed, but passengers later told of their terror.

Genevieve Cousineau, a 25-year-old American who teaches English in Beijing, wrote on Facebook of “the most terrifying moment of my life” as flight CX884 suddenly changed direction and headed for Alaska’s Aleutian Islands.

She said she awoke to find the crew announcing an emergency landing with “people running around, pulling life jackets over our heads, many crying, practising the brace position. We were over the ocean and our plane smelt strange.

“Everyone was in a panic, like, ‘oh my God, this is really happening’. People were putting life-jackets on, the cabin crew were showing us the brace position and helping us practise. This is when people started to freak out. You could just see the fear in people’s eyes.”

Even so, many passengers remained calm enough to take souvenir ‘life-jacket selfies’.

The aircraft touched down without incident before dawn at Eareckson air station, in Shemya – one of the westernmost islands in the Aleutians, more than 1400 miles from Alaska’s largest city, Anchorage.

Cathay Pacific later tweeted that a preliminary investigation had suggested a fault with a cooling fan. Following an inspection the aircraft was deemed safe to fly again, and passengers were taken to Anchorage. Meanwhile another aircraft was dispatched from Hong Kong to pick up the passengers in Anchorage and fly them to Los Angeles.