KLM Flight 633, a Lockheed Constellation Triton passenger flight from Amsterdam to New York City, ditches on a mudbank in the River Shannon immediately after takeoff from Shannon Airport on September 5, 1954. Twenty-eight people are killed in the accident which is caused by an unexpected re-extension of the landing gear, possibly compounded by pilot error.

The Lockheed Super Constellation Triton is piloted by Adriaan Viruly, one of the airline’s most senior pilots. After a refueling stop at Shannon, the plane takes off for the transatlantic leg of the flight at 2:40 AM. There are 46 passengers and ten crew on board. Shortly after takeoff the pilot reduces power from maximum to METO (Maximum Except Take Off). The pilot is unaware that the landing gear is not retracted, and as result the aircraft descends to land in the Shannon. It turns around on impact and breaks into two sections.

The aircraft is partially submerged and at least one of the fuel tanks ruptures during the crash. The fuel fumes render many passengers and crew unconscious, who then drown in the rising tide. In the end, three members of the cabin crew and 25 passengers perish.

Even though the crash occurs less than one minute after the plane takes off from Shannon Airport, airport authorities remain unaware of the disaster until the mud-caked navigator of the craft, Johan Tieman, stumbles into the airport two and a half hours after the crash and reports, “We’ve crashed!” Tieman had swum ashore and floundered painfully across the marshes to the airport, whose lights are clearly visible from the scene of the crash. It is not until 7:00 in the morning that the first launch reaches the survivors, who are huddled on a muddy flat in the river.

The official investigation concludes that the accident is caused by an unexpected re-extension of the landing gear and the captain’s incorrect behaviour in this situation. Viruly, who is only one year from retirement, rejects the responsibility for the crash and is bitter about his subsequent treatment by KLM. In an interview he later states that there simply had not been enough time to react.