A malfunction in the ground instruments at Ben-Gurion Airport nearly caused two passenger planes to crash, Haaretz has learned.
The incident took place early Wednesday morning of the week before last, when visibility at the airport was poor.
The malfunction occurred in the instrument landing system (ILS) on Runway 26, which serves airplanes flying from northeast to southwest. The ILS provides guidance to airplanes landing in difficult weather conditions, such as low cloud ceilings or fog, that prevent pilots from actually seeing the ground until seconds before landing. In such cases, the landing is carried out by the plane's automatic systems, which coordinate the process using data provided by the ILS.
An air traffic controller at Ben-Gurion's control tower discerned from his radar that two airplanes - El Al flight 104 from Toronto and Israir flight 022 from New York - were coming in too low. He informed the pilot of the leading airplane, and was told that the plane was in automatic landing mode and being guided by the ILS.
The controller then realized that because of the malfunction, the two airplanes were coming in at a dangerously flat angle, given the mountainous terrain east of the airport. He therefore redirected them to Larnaca airport in Cyprus.
Had the airplanes kept coming in at the angle recommended by the ILS, they could have hit the ground before reaching the runway.
The Israel Airports Authority has begun investigating the incident. One possible explanation is that thick, tall vegetation in the area of the ILS sensors obstructed the signals that were used to calculate instructions for the planes. Initial attempts to reset the instrument failed, and it returned to normal operation only after the ground around it had been cleared.
The airports authority said in a statement: "On June 3, 2009, Ben-Gurion Airport was operating under poor visibility due to heavy fog in the area of the airport. Two airplanes, belonging to El Al and Israir, attempted landings on Runway 26, which is equipped with ILS. As they were approaching the ground, a traffic controller at the control tower alerted the pilots to the possibility of error in their angle of approach. They understood the error, but couldn't land at the airport due to the poor weather. The slight malfunction in the ILS was fixed that very day. Two calibration flights confirmed that the equipment is now fully operational."
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