A Safer Way for Ships to Do Plane Guard

By Captain Maurice Joyce, U.S. Navy (Retired)

CV NATOPS directs the surface ship serving as plane guard be in “lifeguard station”—yet lifeguard station is not defined in the manual! The definition is in ATP-1(E) Vol. II Allied Maritime Tactical Signal and Maneuvering Book , which identifies lifeguard station as Station LIMA 4: 180 degrees relative 1,000 Yards. All would agree stationing a ship that close to a carrier is not advisable at night. Most carriers have defaulted to stationing plane guard ships on the extended centerline of the landing area known as the “Final Bearing, 170 Relative” to the carrier around 4,000 yards. This stationing likely comes from well-intentioned but misdirected efforts to provide a nighttime reference for landing signal officers (LSOs).

This LSO reference is not mentioned in CV NATOPS either. It finds its origin in two sentences in the lesser-known, lesser-read LSO NATOPS Manual. The LSO manual suggests the use of a plane guard destroyer or helicopter, or even Mk 58 Marine Markers for a reference if needed.

Nonetheless, carriers have coined and institutionalized the term “horizon reference unit” (HRU) to mean a ship acting as a multibillion dollar light bulb for LSOs. (Imagine instead an LSO-controlled drone with a lightbulb hovering at 75 feet as a reference—the strike group would gain a warship!) Without standardized guidance, general practice assumes that since the LSOs are looking down the Final Bearing, that would be ideal. Although LSOs allegedly are remarkable for their exceptional visual acuity, closer mistakenly is assumed to be better.

To train the surface force how to drive ships around the CVN, carriers created the operational tasking (OpTask) Plane Guard, adding dimension to the NATOPS requirement and assigning both HRU and Plane Guard to the same astern station. This guidance was billed as a collaboration between representatives of carrier navigation and air operations departments with the destroyer squadron staff. Absent from this effort were LSOs as well as ship commanding officers (COs).

There are consequences to stationing a destroyer or cruiser so close to the carrier, especially when running fast to make launch and recovery winds. It virtually guarantees the non-carrier CO will be on the bridge closely monitoring the manuevers, instead of in the combat information center (CIC) ready to fight the ship.

More important, though, are health and safety issues for the bridge team and sailors on the destroyer.

On a Case III carrier approach, aircraft begin final descent out of 1200 feet on the final bearing at 3 nm. Bridge team and lookouts of ships on the Final Bearing at 4,000 yards are exposed to the noise of aircraft in a landing configuration flying directly overhead at 500 feet altitude for approximately 10 to15 seconds of each minute during aircraft recovery. Since tactical jet aircraft produce sound pressure levels 130 to 150 dB(A), one can extrapolate sound pressure levels on a ship so stationed could routinely exceed 125 dB(A). Beyond the negative effects on internal and external communications, continuous exposure to such noise levels can be permanently harmful. Aircraft adjusting fuel load for landing weight—dumping JP-5—poses an additional hazard.

In phone interviews with this author in 2013, the LSO School officer-in-charge and the LSOs on the staff of the commanders of Naval Air Atlantic and Pacific all agreed that 4,000 yards is too close to be useful as a horizon reference. The collective conclusion of these fleet experts was that a ship providing horizon reference should be stationed 3 to 5 nm (6,000 to 10,000 yards) astern, on a relative bearing anywhere from the 150 to 210 degrees. The manual for CVN officers-of-the-deck (OODs) offers similar guidance for HRU, but made no refinement of the ambiguous label “Lifeguard Station for Plane Guard.”

Aircraft on final approach at this range of 3 to 5 nautical miles are at an altitude of 1,200 feet. That increased altitude alone more that doubles the distance between the aircraft and ship compared to the aircraft’s 500-foot altitude 4,000 yards astern. Although there are many variables to sound propagation, rule-of-thumb suggests sound pressure level is reduced by half when distance doubles.

Larger safety margins are gained by stationing the ship off the final bearing. The table below, calculated using a radian rule, shows that stationing 10 to 20 degrees off final bearing at 4 nm dramatically increases safety cushion from the high-sound sources. These lateral changes fall within the LSOs’ peripheral sight line. (It also may reduce interference with the carrier’s approach radar induced by a ship parked on final bearing.)

All of this discussion helps position a ship to serve safely as horizon reference. Helicopter are the primary responders to aircraft incidents; thus, it follows logically that nimble surface combatants can be “on station” when within 10 nm (day) or 5 nm (night)—not 4,000 yards.

Beyond attending to the safety of the plane guard ship and her crew, the Navy can save a lot of ship fuel by eliminating tedious “follow-the-leader” reset directives in the OpTask.

A carrier assigned a specific operating area plays a daily dance for sea room and winds. Cyclic air operations usually call for a new launch/recovery cycle to begin every 90 minutes. After chewing up sea room launching and recovering, the less agile carrier usually has to slow before turning and accelerating to run downwind to recapture sea room, and then slow again to turn back to “Foxtrot Corpen” (the course for flight operations) 10 minutes ahead of the next launch cycle. OpTask Plane Guard unimaginatively has the plane guard ship follow behind the carrier, initially turning in the opposite direction of the carrier, then regaining station and chasing through the downwind reset for the inevitable slowing for turn back to Foxtrot Corpen. The carriers are less manueverable than the smaller ships but much faster. These high speed runs are fuel intensive for gas-turbine ships.

With a little bit of math, communication, and imagination the strike group can reduce fuel consumption for the plane guard ship.

Start a 1+30 (90-minute) cycle clock as a carrier starts the launch. In a normal air operations cycle, the carrier will complete the launches and recoveries in 15 minutes. After 5 minutes of slowing, she will commence a 180-degree turn, accelerate for 10 minutes, run for reset, decelerate, and turn again to be on Foxtrot Corpen 10 minutes prior to the next launch. This leaves, at best, 40 minutes for the CVN to run downwind. At a sustained 30 knots, she could cover 20 nm. Through this process, a plane guard cruiser or destroyer in trail would spend most of the time with four gas turbines sucking down fuel at a flank bell.

Alternatively, during aircraft recovery, the CVN OOD would calculate a direction of turn for reset along with a downwind reset course and pass that signal to the plane guard now appropriately stationed no closer than 150 to 210 degrees relative bearing at 3 to 5 nm. The drop down lights on the transom of the carrier (controlled by the air boss)—rather than the masthead tasking lights (controlled by the bridge)—would become the visual cue for the plane guard or reference ship. Completion of fixed-wing ops would be signaled when the air officer turns off the drop down lights.

With the drop down lights extinguished, fixed-wing operations would be secured and plane guard no longer required. That ship could then detach without signal and turn opposite the carrier’s anticipated turn to a course perpendicular to the carrier’s downwind course. At a 17-knot standard bell, this opening move for 7 minutes would add two miles horizontal separation should the carrier overtake during the downwind run. After initially opening the carrier’s downwind course, the ship would turn to parallel the carrier’s downwind, keeping a 17-knot standard bell.

Because the surface combatant doesn’t give up the time to slow, turn, and accelerate twice as the carrier does, the ship has approximately 70 minutes to reposition for the next launch on the air plan. At 17 knots, the ship gets a head start in time and distance, covering 23 nm. In aviation parlance, it’s a “breakup and rendezvous.” Bridge teams have learned to execute this maneuver superbly in the simulator after a 15-minute briefing. In real-world practice, the fuel savings over a workup and deployment cycle would be substantial.

It is counterproductive to have an OpTask for each carrier doing what CV NATOPS and the CVN OOD Manual should be doing. It is time to standardize guidance, nomenclature, and operations. In the absence of clear direction, another maxim of carrier-based aviation—“Take care of your wingman!”—should govern. In this case, keep the safety of the ships and crews in company in the forefront.

Captain Joyce commanded VS-30, the USS Camden (AOE-2), and the John F. Kennedy (CV-67). Since 2011 he has worked for Anchor Innovation Inc. as an Instructor in the Navy’s Navigation, Seamanship, and Shiphandling (NSST) program. He works at the Naval Station Mayport NSST simulator.

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