CHARLESTON, W.Va. -- While the glide slope component of Yeager Airport's instrument landing system is back in operation, its approach light system remains out of service, awaiting re-certification by the Federal Aviation Administration.The approach lighting system (ALS), much of which is mounted on towers extending into neighboring Coonskin Park, was taken out of service when construction was in progress for the extension of the Charleston airport's main runway. In December, during the process of recertifying the approach lights, FAA technicians learned that a device that controls the intensity of the lights had seized up and had to be replaced.Repairs to the system have been completed, according to Yeager officials, but the lights need to be officially recertified by the federal agency before they can be put back in service."We've answered all their [FAA's] questions about the approach lights, but they still need to do something at the tower" before the lights can be put back in operation, said Brian Belcher, Yeager's marketing director. "We don't really know the reason for the delay."Yeager's glide slope system, which had been out of operation since late November and through much of December, allows pilots to complete approaches to the Charleston airport at 200 feet above runway level, with a half-mile of visibility. When both the glide slope and ALS were out of operation, a 700-foot ceiling and 1.5 miles of visibility were needed.Once the ALS is re-certified and operated in conjunction with the glide slope, landings can be completed with a half-mile of visibility and a 200-foot ceiling.A number of flights were canceled or diverted during periods of marginal visibility in December, when both systems were offline.Reach Rick Steelhammer at email@example.com or 304-348-5169.