A instrument landing system (ILS) malfunction at Ben-Gurion Airport in Israel almost caused two aircraft to crash in poor visibility conditions.

The ILS guides the pilots in landing aircraft safely during bad weather conditions, such as low cloud ceilings or fog, that prevent pilots from actually seeing the ground until seconds before landing.

During such conditions, the landing of aircraft is carried out by the plane’s automatic systems, which coordinate the process using data provided by the ILS.

The airport’s air traffic controller detected from his radar that two airplanes – El Al flight 104 from Toronto and Israir flight 022 from New York – were coming in too low.

The controller informed the leading aircraft pilot and was told that plane was in automatic landing mode and being guided by the ILS.

The two airplanes were coming in at a dangerously flat angle due to malfunction in the ILS at the airport. The controller, however, directed the aircraft to Larnaca Airport in Cyprus.

The thick, tall vegetation in the area of the ILS sensors resulted in incorrect instructions for the aircraft.

Steps to reset the instrument failed and it returned to normal operation only after it was clear on the ground. Two calibrated aircraft have confirmed that the equipment is now fully operational.