What happened
On the night of June 5, 1969, a Swissair DC-9-32, registration HB-IFR, was landing at Geneva Airport from Paris-Orly. As the aircraft's nose gear made contact with the runway, the crew spotted an unidentified object on the runway centerline illuminated by the nose light. Because the aircraft was already in the landing phase, an avoidance maneuver was not possible. The aircraft struck the object with its right main landing gear.
Following the impact, the crew experienced heavy vibrations. The captain immediately ordered the reversal of thrust to be stopped and attempted to reduce the load on the nose gear, suspecting damage to the nose wheel. The aircraft eventually came to a stop on the runway without the use of wheel brakes and taxied to a terminal via an access road. There were no fatalities and no injuries among the 83 passengers and 5 crew members on board.
The investigation
The investigation focused on the nature of the object and how it arrived on the runway. At the time of the incident, Geneva Airport was undergoing maintenance to install centerline lighting, which involved drilling holes into the pavement. These holes were temporarily plugged with metal caps weighing approximately 12 kg each.
Investigators identified the object as one of these metallic plugs that had been dislodged from its hole. While the hole was located approximately 960 meters from the start of runway 2/23, the plug was found further down the runway. The investigation examined several possibilities, including whether the plug was left out by workers, placed there by a third party, or moved by aircraft operations.
Findings
- The collision was caused by a metallic plug being present on the runway surface.
- The plug had been displaced from its original borehole, which was intended to be temporarily sealed to ensure safety for light aircraft.
- It was unlikely that the plug was left on the runway since the end of the previous night's work, as routine runway inspections had been conducted throughout the day without detecting any debris.
- The investigation concluded that the most likely cause of the plug's displacement was the jet blast from a large aircraft during takeoff, which provided enough force to eject the object from its socket.