Terrified passengers have recalled the petrifying moment a Singapore Airlines flight plunged suddenly due to turbulence on Tuesday — leaving one man dead and others bloodied and screaming out in pain.

Those on board the Boeing 777 jet said there was virtually no warning before the plane made a “dramatic drop” enroute from London to Singapore Tuesday afternoon.

“Everyone seated and not wearing seatbelt was launched immediately into the ceiling, some people hit their heads on the baggage cabins overhead and dented it, they hit the places where lights and masks are and broke straight through it,” Dzafran Azmir, a 28-year-old student, said.

“There were a lot of spinal and head injuries,” he added.

Another passenger, Andrew Davies, recalled how those with medical training were desperately trying to render aid — including to the 73-year-old British man who died on board after authorities say he suffered a heart attack.

“My heart goes out to the gentleman who lost his life and his poor wife. Awful experience,” Davies, who lives in the UK, tweeted.

“Shouted for a defribulator [sic]. Passengers with medical training helping as much as they could. CPR on the poor gentleman that passed. Another passenger laid flat in aisle further behind me. Not sure what happened with them. Wish I could have helped more.”