Lighting the Way at Eglin
Replacing aging approach lights on Runway 01/19 at Eglin AFB proved a complex challenge, given the project’s location in a sensitive wetland, the need to use Enhanced Use Lease funds, and the requirement to complete construction in a shortened timeline.
By Melinda Rogers, EIT, M.SAME, and Glenn Wagner
Located in the panhandle of Florida and comprising portions of Santa Rosa, Okaloosa and Walton Counties, Eglin AFB is a gem of the Emerald Coast. Containing 724-mi² of reservation that is mostly rangeland and 126,064-mi² of over-water ranges in the Gulf of Mexico, the installation’s airspace, range and test areas are a national asset—both for the mission capabilities they offer and their environmental diversity.
Operated and maintained by the 96th Test Wing within Air Force Materiel Command, Eglin AFB serves several Department of Defense components that are responsible for the complete weapon-system lifecycle—from concept through to development, acquisition, experimental testing, procurement, operational testing, and then final employment in combat. The installation has a rich history that dates back to its beginnings in 1935. With this rich history also comes aging infrastructure.
AN INFRASTRUCTURE CONCERN
Of particular concern for Base Civil Engineers was the approach lighting at the north end of Runway 01/19. Existing creosote-treated structures, which were originally constructed in 1970, were becoming structurally unsound due to their age. They had light fixtures that were obsolete and they did not meet current Federal Aviation Administration (FAA) frangibility requirements.
Furthermore, the structures presented a safety hazard for airfield lighting craftsmen, as the lights could only be accessed by climbing up 40-ft rungs on the side of the poles. At no time, however, was there ever a safety concern or compromise to safety with respect to aircraft operations or the flying community.
Another complicating factor was that the approach lights were located in Toms Creek, a wetland area designated as habitat for the federally listed Okaloosa darter. The entire global population of this species is found in the tributaries and main channels of Toms, Turkey, Mill, Swift, Turkey-Bolton and Rocky Creeks, which drain into two bayous of Choctawhatchee Bay. Eglin AFB has management responsibility for 90 percent of the 176-mi² drainage area. The remaining portions of the watershed are within the urban areas of Niceville and Valparaiso. At issue were the timber approach light structures, which were pressure-treated with creosote that was leaching into the water. This presented a major concern for the Okaloosa darter habitat.
The primary purposes of the renovation project were mission-driven: to bring aircraft approach lighting up to current FAA frangibility standards and to provide a safe platform for craftsmen to perform maintenance on the aircraft approach lights. Additionally, the project sought to prevent environmental impacts to the wetlands and to improve the Okaloosa darter habitat.
The scope of the repair work was to replace the eight light structures at the end of Runway 01/19 with new FAA-approved frangible fixtures and add ladders with safety cages for ascending and descending the light platforms. For several years, this requirement remained unfunded due to limited sustainment, restoration and modernization dollars available for base infrastructure as a result of funds being allocated to overseas contingency operations.
Meanwhile, Eglin AFB’s Enhanced Use Lease (EUL) Program started gaining steam. Through EULs, the U.S. Air Force leases under-utilized, non-excess real property assets to commercial developers or municipalities for fair market value rent. This rent is normally received by the Air Force as payment-in-kind projects. At Eglin, an easement was granted to the Mid-Bay Bridge Authority for an 11-mi toll road across federal property. As payment for this easement, the Mid-Bay Bridge Authority performed numerous infrastructure projects around the base that were requested by Eglin’s civil engineering leadership. Reinvesting EUL dollars into aging base infrastructure is a concept that can be modeled at other defense installations.
Beginning in 2011, Eglin’s civil engineers teamed with HDR to provide the environmental assessment, design and permitting services. The HDR team, including environmental, electrical, airfield, and structural design experts, worked closely with the base team to ensure success. The synergy among so many base components—including operations, asset management, environmental, planning, design and construction personnel, along with the close involvement of the airfield manager—was a unique and rewarding aspect of the work.
The project presented a number of technical challenges to overcome: a limited construction area and equipment access; the need to bridge the creek during construction activities; maintaining a bad weather landing capability; maintaining a full flying schedule; and working in an environmentally sensitive area.
The design team excelled in overcoming each of these challenges. The site is constrained on all sides. The creek meanders right through the middle while there are wetlands on the north and south sides. The east side is constrained by the base commercial access drive and the west side is constrained by a steep hill that leads up to Runway 01/19. To provide safe access to the lights for maintenance, HDR’s design included platforms 15-ft to 20-ft above the boardwalk, and light structures that crank down to the platform level. The design also required that the existing creek be temporarily bridged during construction in order to access and install the two structures closest to the runway.
The project’s truncated timeline presented another challenge. The renovation was scheduled so that the bulk of heavy construction involving lighting structures was conducted through the fall and winter months (September 2013 to February 2014), when winds patterns are predominantly from the north. Because most aircraft land from the south approach, possible north approach runway closures would be significantly reduced or eliminated. Air traffic controllers had to continue a normal fly schedule with only one runway and limited use of the other.
Additionally, with the work being conducted in an environmentally sensitive area, an Environmental Assessment needed to be performed for the Air Force. Regulatory agencies were consulted early about the approach to replacing the lighting structures. Headquarters Air Force Materiel Command signed a Finding of No Practicable Alternative for the project.
The project team turned each of the challenges into opportunities to excel. The Air Force awarded construction to EMR Inc. on Aug. 29, 2013, for $1.7 million, with work beginning on Sept. 17, 2013. The approach lights construction was completed on Sept. 16, 2014, and the system has been in operation since that time.
Airfield lighting craftsmen no longer have the safety concerns they once had, the waters of Toms Creek are cleaner, and the habitat is safe for the Okaloosa darter.