Malév Flight 731

Malév Hungarian Airlines

Industry	Airline
Founded	1946
Headquarters	Budapest , Hungary

Malév Hungarian Airlines Flight 731 was operating a scheduled route from Oslo-Fornebu Airport to Budapest Ferihegy International Airport, with planned stops at Copenhagen Airport and Berlin Schönefeld Airport. On 28 August 1971, amid severe rainfall, the aircraft—a registered HA-MOC Ilyushin Il-18—plunged into the sea roughly 600 meters off the northern shore of Saltholm, approximately 10 kilometers from the airport. Out of 25 passengers and nine crew members onboard, only two individuals survived. The flight was commanded by Captain Dezső Szentgyörgyi, renowned as the top-scoring Hungarian fighter ace of the Royal Hungarian Air Force during World War II.

Aircraft

The plane involved was an Ilyushin Il-18V built in 1961, bearing the registration HA-MOC. This model had been part of Malév's fleet since its introduction. It was powered by four Ivchenko AI-20K engines. Following the accident, the aircraft wreckage was retrieved from the sea and transported to Copenhagen for detailed examination.

Flight

The flight departed from Oslo, Norway's capital, on its scheduled journey to Budapest, with intermediate stops in Copenhagen, Denmark, and East Berlin, then the capital of East Germany. The decade-old plane experienced a routine flight over the Scandinavian Peninsula before turning westward over the Øresund strait to approach Copenhagen Airport. At that time, a severe thunderstorm affected the Danish coastline, resulting in low visibility conditions. Throughout this period, communication with air traffic control remained consistent. At 19:42 local time, clearance was granted for descent from an altitude of 3,300 meters in preparation for landing. The engines’ power was reduced accordingly as the descent commenced. Upon reaching 500 meters at 19:52, the landing gear was deployed. Mere seconds later, radio contact was lost. Within less than thirty seconds after losing communication, the aircraft crashed into the sea and fragmented into three parts; most of the passenger cabin submerged underwater. The crash site was located only about ten kilometers from Copenhagen Airport.

One survivor from Germany, Jürgen Hermann, recounted to a Népszava journalist: "It was raining outside. The cabin lights were dimmed as usual when suddenly a violent shaking occurred and then complete darkness engulfed us. (...) Without hesitation, I leapt over my companion’s head and crawled toward a faint light behind me. The tail wing detached from the plane as I sought refuge from the rapidly rising water. Gradually in the darkness, I realized that the plane’s nose had plunged into the sea while its tail protruded about a meter above the turbulent water."

Initially believing himself to be alone among survivors, Hermann soon heard voices amid the water. He succeeded in pulling another survivor—a young woman from West Berlin—up to a vertical ledge where he stood; her mother-in-law, aged 59, clung to another piece of debris nearby. A flight attendant was also found in the water; although he communicated briefly with the two women, he later succumbed to drowning. Medical reports indicated that four passengers and two crew members died due to injuries sustained in impact; others perished by drowning. After radar contact was lost and no response came from the aircraft following controller calls, an emergency alert was issued immediately and rescue vessels were dispatched to the estimated crash location. Wreckage was located twenty minutes later with three survivors aboard; however, one passed away in hospital three days afterward, leaving just two survivors.

Aftermath

The majority of the aircraft's debris and its engines were retrieved from the ocean. The inquiry uncovered that the plane was not equipped with flight recorders, contravening the ICAO mandate for propeller-driven gas turbine planes exceeding 5,700 kg. Since Hungary joined the UN's International Civil Aviation Organisation in 1969, compliance with these regulations should have been enforced thereafter. Additionally, the cockpit was missing a voice recorder. Despite adverse weather conditions, no restrictions on landings were implemented, and airport operations continued without interruption. Throughout the flight, significant shifts in wind direction and velocity occurred, resulting in a phenomenon known as wind shear, which exerts a lateral force on the aircraft. Pilots can counteract this by applying full engine thrust. This effect was understood at the time of the incident, leaving investigators puzzled as to why Dezső Szentgyörgyi and his team did not respond accordingly.

The true cause of the tragedy was identified only over ten years later: a highly hazardous variant of wind shear, termed a microburst, which was not recognized in 1971. A downburst consists of an intense, high-energy downdraft confined to a relatively small area. While commonly linked to thunderstorms, it can also manifest independently. An aircraft entrapped in such a downdraft may experience descent rates of 20–30 metres per second, posing severe risks during takeoff or landing phases. The microburst’s brief duration—typically between 5 and 10 minutes—makes timely detection challenging. Presently, specialized weather radar systems are deployed around airports to identify and mitigate microbursts. Efforts to address this hazard gained momentum following the crash of Delta Air Lines Flight 191.