On 8 November 1963, the aircraft serving the flight crashed in poor visibility while attempting to land on a non-precision approach at Mariehamn Airport in the municipality of Jomala, resulting in the deaths of 22 people out of 25 on board.

[1] Aero Flight 217, operated with a Douglas DC-3, was scheduled to take off at 14:50 GMT and travel along the Helsinki-Turku-Mariehamn route from Helsinki Airport.

The plane hit the ground after rotating leftwards on its longitudinal axis, landing upside down and immediately catching fire.

[2]: 20 The AIB investigation concluded that the crash happened because of lack of awareness on the part of the pilots, either of the plane's altitude or of its location.

Another Aero O/Y pilot who had flown the accident aircraft, one Captain Tamminen, had informed investigators that the altimeter had erroneously shown an altitude fifty feet higher than normal the day before the flight.

[2]: 23  However, the AIB stated that it was unlikely as Flight 217 flew very close to the beacon, which meant the signal must have been strong and that the likely reason was the pilots' misconception of the altitude instead.

[2]: 23 The AIB recommended that airlines use stricter weather standards than those prescribed by the International Civil Aviation Organization's Obstruction Clearance Limit (OCL).

[2]: 25 Wreckage from the aircraft was left in the forest in the vicinity of Mariehamn Airport for nearly 55 years, before being removed in 2018 due to environmental concerns.