Geoff Kitchen is believed to have been sitting next to his wife Linda when Flight SQ321 hit severe turbulence over the Indian Ocean and dropped around 1800m in three minutes.
The 73-year-old British man died in his seat of a heart attack, while his wife suffered severe spinal injuries, according to the Daily Mail.
With dozens injured, the plane was diverted to Bangkok where 79 people were taken off the flight.
Singapore Airlines chief executive Goh Choon Phong released a statement following the flight, saying: “On behalf of Singapore Airlines, I would like to express my deepest condolences to the family and loved ones of the deceased passenger.
“We also deeply apologise for the trauma experienced by all passengers and crew members on this flight.
“We are providing all possible assistance and support to them, along with their families and loved ones, during this difficult time. The wellbeing of our passengers and staff is our utmost priority.”