Sixty years ago: crash of Sabena flight SN548 (Boeing 707) in Berg, Belgium, killing 73 people

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On 15 February 1961, a Sabena Belgian World Airlines Boeing 707-329 aircraft registered OO-SJB operating flight SN548 crashed en route from New York City to Brussels, Belgium. The flight, which had originated at Idlewild International Airport (now John F. Kennedy International Airport), crashed on approach to Zaventem Airport, Brussels, killing all 72 people on board (including 11 crew members) and one person on the ground.

The fatalities included the entire U.S. Figure Skating team, who were travelling to the World Figure Skating Championships in Prague, Czechoslovakia.

The precise cause of the crash remains a mystery; the most likely explanation was thought to be a failure of the tail stabiliser-adjusting mechanism.

This was the first fatal accident involving a Boeing 707 in regular passenger service; it happened 28 months after the Boeing 707 airliner was placed into commercial use. It remains the deadliest plane crash ever to occur on Belgian soil.

Inauguration of a monument

The 40th anniversary of the crash was marked by the unveiling of a 1.50-metre-high stone monument in Berg-Kampenhout, close to the scene of the tragedy. Local dignitaries attended the unveiling ceremony which took place on 10 February 2001.

On 15 February 2021 at 10:05 (UTC+1), the municipality of Kampenhout will unveil a new monument to commemorate the Sabena crash in the Berg district. As a result of the corona measures, the ceremony takes place in a very limited circle. Only four people will be present, including Kris Leaerts, the mayor of Kampenhout. He will place a wreath at the monument and give a speech. The “Last Post” will be played. The wife of the victim who lost his leg (see hereunder) will also be present.

The accident

There were eleven crew members on board the ill-fated flight. The two pilots, Louis Lambrechts and Jean Roy, were both experienced ex-army pilots. There were no difficulties reported during the seven and a half hour trans-Atlantic flight from New York; there was no indication that the plane was in any particular trouble, although the flight crew did lose radio contact with Brussels airport about twenty minutes before coming in to land.

Under clear skies, at about 10:00 Brussels time (CET; 09:00 UTC), the Boeing 707 was on a long approach to Runway 20 when, near the runway threshold and at a height of 900 feet (270 m), power was increased and the landing gear retracted. The aeroplane had been forced to cancel its final approach to Brussels airport, as a small plane had not yet cleared the runway.

The 707 circled the airport and made another attempt to land on adjoining Runway 25, which was not operational; this second approach was also aborted. It became clear to observers that the pilots were fighting for control of the aircraft, making a desperate attempt to land despite the fact that a mechanical malfunction was preventing them from making a normal landing. The plane circled the airfield three times altogether, during which the bank angle gradually increased until the aircraft had climbed to 1,500 feet (460 m) and was in a near-vertical bank. It then levelled its wings, pitched up abruptly, lost speed and spiralled rapidly nose down, plunging into the ground less than two miles (3 km) from the airport, at 10:05 CET (09:05 UTC).

Sabena Boeing 707-329 OO-SJA on short finals in Brussels in 1960 © Wikimedia

The location of the crash was a marshy area adjacent to farmland near Berg (then an independent municipality, nowadays part of Kampenhout), seven kilometres northeast of Brussels. Eyewitnesses said that the plane exploded when it hit the ground and heavy black smoke was seen coming from the wreckage which had burst into flames.

Theo de Laet, a young endive farmer and noted amateur cyclist, who was working in a field near to the crash site, was killed by a piece of aluminium shrapnel from the plane. Another field worker, Marcel Lauwers, was also hit by flying debris which amputated part of his leg.

Father Joseph Cuyt, a local priest who had been observing the aeroplane as it came in to land, rushed to the scene but was driven back by the intense heat of the fire.[9] Airport rescue vehicles arrived at the crash site almost immediately but the plane was already a blazing bonfire. It is believed that all 72 occupants of the plane were killed instantly on impact.

Baudouin I, King of the Belgians, and his consort, Queen Fabiola, travelled to the scene of the disaster[ to provide comfort to the bereaved families. They donated oak coffins bearing the royal seal to transport the bodies back home.

In office for less than a month, President John F. Kennedy issued a statement of condolence from the White House, which read: “Our country has sustained a great loss of talent and grace which had brought pleasure to people all over the world. Mrs Kennedy and I extend our deepest sympathy to the families and friends of all the passengers and crew who died in this crash. He was particularly affected by the tragedy; pairs skater Dudley Richards was a personal friend of the president and his brother Ted.

Investigation

The Belgian Government immediately ordered a full inquiry into the cause of the accident, and an investigation was conducted by the Belgian National authorities, the United States Federal Aviation Administration (FAA), and the International Civil Aviation Organization (ICAO), who spent several months combing through the evidence. There was much speculation about what may have happened; the FBI even reportedly considered the possibility of terrorism.

The exact cause of the crash was never fully determined, but the authorities eventually agreed that the most likely explanation was a mechanical failure of one of the flight control mechanisms, probably a malfunction of either the wing spoilers or the tail stabilisers. Although there was insufficient evidence to prove beyond reasonable doubt which of the flight systems had malfunctioned, the FAA were of the opinion that the tail stabiliser-adjusting mechanism had failed, allowing the stabiliser to run to the “10.5° nose-up position“.

Sources: Wikipedia and recent Belgian media

Comment

A former Boeing 707 first officer who requested anonymity told us that:

  • the stabiliser ran away full pitch up,
  • when the aircraft neared stall at high pitch, the crew banked the aircraft in order to let the nose go down and to regain airspeed, hence some aerodynamic control,
  • they re-did 2 or 3 times, then lost control.

He added that shortly after that SN548 accident, an emergency procedure was developed that required the crew to pull-out several circuit breakers in order to stop the runaway. Months later, that procedure was enhanced by the retrofitting of two “stabiliser cutout switches“ on the aft-right of the centre pedestal, that enabled the crew to

  1. cut-off electrical power to the stabiliser
  2. manually manoeuvre the stabiliser trim wheel in the flight deck thanks to two manual handles

These switches were also installed on the B727, B737 & B747 (see green arrow on B747 pedestal pictured hereunder)

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