About 15 years ago a group of artisans assigned to Fleet Readiness Center Southwests (FRCSW) Voyage Repair Team (VRT) boarded the USS Carl Vinson (CVN 70) to complete overhaul training to the Improved Fresnel Lens Optical Landing System (IFLOLS).
IFLOLS is a visual landing aid that uses lights to assist pilots in determining the proper glide slope when landing on flight decks or airfields. Pilots use IFLOLS within three nautical of landing aboard ship.
The unit is comprised of an aluminum frame display that houses lights that are located on the edge of the flight deck, and a computerized control center located in a protected area of the ship.
The first Fresnel Landing System was designed almost 60 years ago to replace the Mirror Optical Landing System (MOLS). MOLS used a large curved mirror used in conjunction with three source lights. Pilots established a glide slope by the position of a reflected light off the mirror.
A primary difference between the two systems is the lens. The MOLS plastic-type Fresnel lens was subject to weathering more easily than the fiber optics and glass lenses of the IFLOLS.
Exposure to the harsh environment of deployed Navy ships and the corrosive effects of seawater often result in overhaul to the deck edge portion of IFLOLS that are in fleet service for more than five years.
If a shipboard IFLOLS fails, Sailors substitute the Manual Visual Landing Aid System, which is similar to IFLOLS, only portable.
The difference between shore and ship-based systems are the Stabilized Optic Tables (SOT), which hold 12 fiber optic units that house two 80-watt bulbs each. The ship-based IFLOLS system has a ball screw assembly that moves the SOT in relation to the vessels movement, using the ships gyro system. SOTs on shore-based systems are fixed.
FRCSWs VRT overhauled its first shore-based IFLOLS in 2015.
That system belonged to Naval Auxiliary Landing Field (NALF) on San Clemente Island, and was modified by the Naval Air Warfare Center under the engineering guide of Naval Air Systems Command (NAVAIR).
The NALF system is comprised of five parts: The first houses all 12 SOTs; the datum arms that hold the aviation green lights on the port and starboard side of the SOTs; electronic and transformer enclosure assemblies; and a movable trailer. Overhaul to the unit took about six months.
Overhauled ship and shore-based IFLOLS -- and all other landing aids -- require certification from the Carrier Air Field Support Unit (CAFSU). CAFSU serves as the liaison to the fleet and VRT.
FRCSWs VRT is the only facility on the West Coast certified to work on the IFLOLS.