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 | 1.00k | An SH-60B Seahawk helicopter lifts off from the guided missile destroyer Mason (DDG-87) to conduct an aerial security patrol over the Central Persian Gulf. LAMPS Mk.III with the SH-60B Seahawk ASW helicopter, a far more capable aircraft than the smaller Seasprite, was the weapon to attack convergence- zone contacts made by the SQR-19 TACTAS towed-array sonar. The TACTAS sonar detected contacts in the second and third convergence zones and the Seahawk helicopter could localize and prosecute contacts at those ranges. The second convergence zone was a practical limit. Distance to a third-convergence zone contact was around 100 miles, so the tactical commander of an ASW force would prefer to send a faster fixed-wing ASW aircraft such as the S-3 Viking, the P-3 Orion or an allied counterpart. The backbone of LAMPS Mk.3 was the “Hawk Link” microwave data link, between the shipboard SRQ-4 and the SH-60B's ARQ-44 data link radios. It superseded the LAMPS Mk.1 one-way sonobuoy signal relay and eliminated the need to use TACAN (tactical air navigation) beacons and UHF (ultra-high-frequency) voice radios during LAMPS missions. The ship transmitted contact data from all sensors over the Hawk Link directly into the Seahawk's mission computer for immediate display on the aircraft's consoles. Similarly, the helicopter transmitted contacts from its sensors to the ship. The helicopter had better surface-search radar coverage than the ship and provided an automatic cross-fix on ESM rackets (detected electronic signals) and did not reveal the location of the ship to enemy targeting systems. These were extremely useful services. Force ASW coordinators often found that SH-60B missions were oriented toward surface patrol than ASW patrol. Helicopters gave ships a long-range, fast-response ASW capability; A plan for a helicopter ASW mission balanced range, payload and time on station. Sonobuoys transmitted their signals over VHF radio channels. In high sea states waves quenched sonobuoys and could block the radio to the ship. The SH-60B carried an acoustic-signal processor to analyze sonobuoy signals independently. A new acoustic-signal processor, SQQ-28, analyzed sonobuoy contact data aboard ship. Often the ship would monitor the sonobuoys so that the Hawk Link was free to transmit the helicopter's surface radar picture. The 99-channel capability let the ship and aircraft monitor multiple sonobuoy fields simultaneously and switched attention to new sonobuoys while old ones were still transmitting. During a ASW patrol a destroyer kept a helicopter on deck on alert, loaded with sonobuoys, fuel, smoke floats and a torpedo. Given a sonar contact or intelligence report of a submarine, the helicopter launched. The operations watch in the combat information center used the Command and decision System to vector the helicopter to the contact area and to plan sonobuoy drop patterns. A major value of LAMPS was that the helicopter could fly quickly to the contact area to start determining whether a contact could in fact be a target. The ship had to spend less time tied down by false alarms and was les likely to waste ordnance on urgent shots against false contacts. The combat information center estimated the target's position, course and speed and vectored the helicopter to drop sonobuoys around that location. Data were entered into the underwater fire control system which computed a torpedo drop point. The helicopter dropped patterns of sonobuoys until the target was redetected or until the original contact was evaluated as a false alarm or as having escaped. The helicopter could detect the submarine's steel hull magnetically or make an above-water detection with radar, ESM equipment or aircrew sighting. The aircraft commander would drop the torpedo when sensor data or unambiquous detection gave confidence that the submarine was within the torpedo's acquisition range. Helicopter takeoffs and landings were limited to sea states in which the ship did not roll prohibitively. Acceptable conditions occurred in the North Atlantic only 69 percent of the time during winter or less considering precipitation, icing and limited visibility. Frigates were more affected than destroyers and could operate helicopters just 25 percent of the time in the same seas. Since oceanic storms were neutral and covered large areas, this situation was acceptable if Soviet naval forces were themselves unable to attack with long-range antiship missiles in the same weather. The Canadian RAST (recovery assist, secure and traversing) system was installed for landing and flight deck handling of the heavier SH-60B helicopters. RAST supported helicopter operations during sea state 5 conditions that would ground helicopters flying from conventional shipboard flight decks. The landing signal officer worked in a station with bulletproof windows that gave a view of the deck. To land, the SH-60B hovered about 15-20 feet above the deck and dropped a messenger line from a probe on the bottom of the fuselage. Flight deck crewmen hooked the line to a cable from the RAST deck trolley (recovery securing device or RSD). RAST winched the helicopter down to the deck trolley and latched onto the probe. After the helicopter shut down and folded its rotor blades, the trolley pulled the helicopter into the hangar. The pilot could release RAST and land without it. RAST was still necessary to traverse the aircraft into the hangar. Launch was similar. The trolley moved the SH-60B onto the flight deck, where the helicopter spread its rotor blades and started its engines. When the pilot signalled ready for takeoff, the landing signal officer released RAST's grip on the probe. The helicopter ascended, received a visual check from the landings officer, turned 45-60 degrees off the centreline and departed. Keel slamming could restrict ASW operations during heavy weather, sea state 6 (12-foot waves) or worse. The ship had to steer a parallel course to hold a submarine in a convergence zone or in direct pursuit, but frequent slamming could deter the ship from keeping that course. A dominant feature of the Arleigh Burke (DDG-51) design is its broad waterplane hull that improved seakeeping in the rough northern seas. Arleigh Burke's design sacrifed speed, range and at first, helicopter facility which suggest its operational importance. | Photographs & text courtesy of Pieter Bakels. | |
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