"Roger Ball" high tech style

Wings of Gold, Summer 2002 by Holland, Art

Wings of Gold Feature

"On the Flight Deck-aircrews are manning for the Event two, Case one launch! It's time for all personnel to get into the proper Flight Deck uniform. That's helmets on, goggles down, sleeves rolled down ..."

With this emphatic announcement over the 5MC Flight Deck announcing system the Air Boss begins the next evolution of the Aircraft Carrier's cyclic flight operations. As the last aircraft from this cycle are launched, the Flight Deck crew hustles to secure the catapults and man recovery stations for aircraft returning from the previous cycle. The hard work is just beginning; both for the flight deck crew and the aviators that will bring the returning aircraft back aboard.

Landing a high performance jet aircraft aboard a pitching, moving runway at sea is one of the most precise and demanding flying tasks in all of aviation. The ability to project effective combat power from the sea depends heavily on the ability of pilots to safely recover back aboard the ship, regardless of weather, sea conditions, or time of day. To ease their workload in this critical phase of Carrier operations, an impressive array of equipment is now being used. This article describes some of the latest information and aircraft data management systems being fielded to allow aircrew and carrier personnel to operate more efficiently and safely around the ship. Each of the advanced systems described has been installed aboard the carrier fleet or will be in the near future.

From the Landing Signal Officers' (LSO) first use of paddles to the LSO-- controlled mirror that relies on a reflected light beam to represent the optimum approach path, landing systems have been steadily evolving to provide the pilot with consistently better visual approach and landing information. The first major improvement was the Fresnel Lens Optical Landing Sys- tem (FLOLS) introduced in the early 1960's. Named after its inventor, Augustin Fresnel, this system uses compound lenses instead of mirrors. The five optics cells that make up the Fresnel Lens are confined within a stabilized frame located on the port deck edge of the Flight Deck. With FLOLS, there are five separate light cells that indicate the aircraft's relationship to a central glide slope. When on optimum glide path, the pilot sees an amber light, commonly referred to as the "meatball," centered between two fixed green horizontal datum line reference bars. If the aircraft is above glide path, the pilot perceives the meatball above the datum line, and when the aircraft is below the optimum glide path, the pilot sees the amber light below the datum line. When the pilot sees a red light in the bottom cell, the aircraft is dangerously low.

The original FLOLS used an analog computer-stabilization system to produce a stable beam of light in space. With the introductionof the Im- proved Fresnel Lens Optical Landing System (IFLOLS), landing guidance technology has progressed from a mechanical analog computer to an internally stabilized, digitallycontrolled system.

Where FLOLS uses large servomotors to move the entire indicator assembly to compensate for ship movement, IFLOLS is stationary, using internally stabilized optics to move the lamps and image forming fiber optic blocks. This innovative design provides vast improvements instabilization, control and reliability.

Critical to system performance is display sensitivity which is how far the meatball will move above and below the datum lights for a given displacement of the aircraft. IFOLS is one and one-half times more sensitive than FLOLS.

Another important factor is the increased vertical dimension of the IFLOLS system - 72 inches high versus the 50-inch height of FLOLS. While glide slope coverage for both systems is the same - 1.7 degrees high by 40 degrees wide - the larger IFLOLS display can be seen at a greater distance from the ship. FLOLS has a useful range of about three quarters of a nautical mile (nm), whereas IFLOLS visual cues are usable out to 1.25 nm. Earlier acquisition of the ball coupled with increased sensitivity allows the pilot an opportunity to detect smaller deviations from glide slope much sooner, allowing more timely corrections.

IFLOLS met its Initial Operational Capability (IOC) in March 2001 aboard USS John C. Stennis (CVN-74), and will be installed on all remaining carriers by 2003.

Another new landing aid for the pilot is the Long Range Lineup System (LRLS). It is mounted just below the flight deck on the aft end of the ship. The main unit contains an optical head containing 10 Lasers (4 Red, 1 Yellow, 5 green), masks, and filters which form 7 corridors indicating position of aircraft relative to flight deck centerline. A base houses the power supply and the pitch/ roll stabilization system.

LRLS provides line-up information to the pilot from six nm to about .65 nm astern the ship. LRLS complements IFLOLS by providing visual cues to the pilot that facilitate the early interception of centerline at night. When on centerline the pilot sees a yellow light. When deviations occur, the pilot will see either a steady green light, if right of centerline, or a steady red light when the aircraft is lined up to the left. As deviation increases to the left or right, the corresponding light begins to flash. The more rapidly the lights flash, the further the pilot is away from an optimum flight path. LRLS augments the existing Automatic Carrier landing Sys- tem (ACLS), Instrument Landing System (ILS) and Visual Landing Aids (VLA) by allowing a more seamless transition from instruments to visual cues for landing. Because it provides a more accurate means of evaluating position left or right of centerline, LRLS ensures lineup remains a prominent part of the pilot's visual scan. By reducing the requirement for closein line-up corrections, as well as minimizing radio transmissions between the pilot and the LSOs, LRLS is effective in decreasing pilot workload and increasing con- fidence.