An urgent warning has been issued after a pilot veered off course when he mistook roof-top lights on a high-rise building in Santry as Dublin airport runway approach lights.
In a preliminary report on what he describes as a "serious incident", air accident investigator Leo Murray says the roof-lights on the building in Santry resemble the red and white approach lights to runway 34 at Dublin Airport
On August 16, the pilot of the Flightline-chartered McDonnell Douglas DC9 with 117 passengers and crew abroad began to deviate left of the approach course about five miles from touchdown.
"The aircraft continued to descend below the MDA (Minimum Descent Altitude) without proper visual identification of the runway in use.
"On the instruction of Air Traffic Control (ATC) the aircraft turned right and climbed to a safe altitude."
The report says the aircraft, which had flown from Lisbon, was given radar settings for an approach to another runway and landed without further incident.
Subsequently, the Air Accident Investigation Unit conducted a series of approaches to runway 34 to see what had caused the pilot to veer off course.
"It was found that lighting from a 16-storey building situated at Santry Cross appeared, at night, to resemble the red and white lights of a runway approach light system.
"The building is equipped with four fixed red obstacle lights situated on the roof."
Earlier this month Mr Murray and the chief inspector of air accidents briefed the Irish Aviation Authority's director of safety regulation.
As a result of the investigators' concerns, he immediately issued an air traffic services operations notice.
The warning notice requires that, when runway 34 is in use, all air traffic control broadcasts should include the caution that lights on the building a mile and a half south-west of the runway "have the potential to disorientate flight crews".
Mr Murray's report also calls on the IAA to "review the suitability of obstacle lighting" installed on the 52 metre-high Santry Cross building.