During the Second World War the Royal Air Force developed a radar equipped Hudson bomber to seek out German U-boats. These explorations into anti-submarine warfare aircraft led to the Lockheed PV-1 Ventura and PV-2 Harpoon which was a major redesign of the Ventura. The United States Navy contracted Lockheed near the end of the war to design prototypes of a land-based patrol bomber. Originally called Guardian by Lockheed, their prototype XP2V-1 would become known as the Neptune, which first flew on the 17th of May, 1945. Production aircraft were delivered to the United States Navy in July 1946 and entered service in March 1947.
The first Neptunes to enter service with the United States Navy demonstrated impressive performance for the time – with a maximum range of 6,649 kilometres (or 4,131 miles) with a cruising speed of 281 km/h (175 mph) and a maximum speed of 486km/h (302mph).
A heavily modified third production P2V-1 aircraft nicknamed ‘The Truculent Turtle’ flew from RAAF Pearce in Western Australia to Columbus, Ohio. The fifty-five hour and seventeen-minute flight, which started on the 29th of September 1946, flew non-stop and without refueling, across Australia and the Pacific, a distance of 18,081 km (11,235 miles). The flight also carried a gift from Australia to the Washington National Zoo – a kangaroo!
By 1949 the P2V-4 variant was fitted with more powerful engines, the AN/APS-20 radar and could drop and monitor sonobuoys. The following variant, the P2V-5, would be the most produced variant and the first to be exported. The RAAF needed a long-range maritime patrol aircraft to replace the aging Avro Lincolns and to cover Australia’s Maritime Surveillance Area of Responsibility, which was enormous. By February 1951, orders were placed for Neptunes to re-equip No. 11 Squadron, and deliveries started to arrive in November of that year. The 12 aircraft were up to P2V-5 standard and sported the standard United States Navy scheme of overall gloss Sea Blue.
The Neptunes anti-submarine and anti-surface capabilities included the AN/APS-20 search radar with a range of 370km, the AN/APS-31 attack radar with a range of 45km, Electronic Counter Measures, searchlight, 40 sonobuoys and acoustic receivers, bomb bay mounted torpedoes, sea mines, depth charges and underwing rails for rockets.
It was quite a leap in technology from the Lincolns and the ten-man crew required a significant amount of training in both systems and tactics, which would ultimately culminate in complex joint multi-national exercises. Neptune crews found themselves operating from remote bases such as the Cocos Islands, Christmas Island, Papua New Guinea, and regular deployments to Malaya, Philippines and Thailand. They maintained a Search and Rescue standby commitment as well as routine maritime patrols and joint training exercises with the Royal Navy and the Royal Australian Navy.
In May 1954, 11 Squadron moved to RAAF base Richmond to be closer to the Royal Australian Navy units around Sydney.
In 1957, three 11 Squadron Neptunes conducted perimeter patrols around a British nuclear testing area at the Montebello Islands off the north-western Australian coast. The two tests which were conducted in May and June the previous year, named Operation Mosaic, would be the largest nuclear test in Australia (the second test yielding 60 kilotons).
It was also in 1957 that three RAAF Neptunes completed an around-the-world flight, known as Operation Westbound, covering 50,000km and showcasing the Neptune’s long-range ability and navigation prowess.
In November 1958 and February 1959, four Neptunes provided coverage and radio homing for 35 Sabres flying from Williamtown in New South Wales to Butterworth in Malaya. Sadly, on the 4th of February 1959, at Richmond, an engine fire burned through a wing spar causing the wing to fold and the aircraft inverted at low level while attempting an emergency landing. Squadron Leader Geoffrey Cullen and his crew were killed on the banks of the Hawkesbury River, not far from the perimeter of Richmond Air Base. This was the only Neptune to be lost in RAAF service.
It was also in 1959 that Neptunes of 11 Squadron participated in the Joint Australian Anti-Submarine School research off the South Australian coast with British Warships. These exercises trained Neptune crews in anti-submarine tactics and included the Weapons Research Establishments research trials in anti-submarine radars.
The original mark one P2V-5s were upgraded with the Magnetic Anomaly Detector tail boom, providing the capability to localise submerged submarines for accurate targeting. The nose turret was also replaced with a clear nose and the dorsal turret removed. From June to December 1959, 11 aircraft were upgraded at the Lockheed facility at Ontario, California, to be fitted with Westinghouse J34 turbojets under the wings.
By September 1960, number 10 Squadron had ordered 12 P2V-7 Neptunes to replace the ageing, Lincolns. Between March and May, 1962, the new Neptunes arrived in Townsville for the squadron, proving major improvements for anti-submarine tasking. The AN/AQA-4 passive acoustic Jezebel system could localise and classify submarines with passive sonobuoys. Also equipped with the AN/ASA-20 Julie active short range explosive echo ranging system and AN/AQA-1 for active range-only sonobuoys, a state-of-the-art suite for the time. With a range of other electronic support measures and a diesel fuel ‘sniffer’ system, this aircraft, now re-designated SP-2H, became the primary maritime patrol aircraft for Australia. Operations such as Gay Rover and Galley Slave saw the Neptune operate out of Learmonth, Cocos Islands, and Butterworth, where Soviet submarines would often be encountered.
On the 10th of February, 1964, number 11 Squadron P-2Es were involved in the response to the collision between HMAS Melbourne and HMAS Voyager off Jervis Bay in New South Wales. And in 1971, 10 Squadron searched for the crew of the abandoned ketch ‘One and All’, off the Queensland coast. A Neptune sighted the survivors and vectored the RAN submarine HMAS Otway onto their position where they were rescued.
In 1965, the 1st Battalion of the Royal Australian Regiment was being transported to Vietnam on HMAS Sydney. Due to the threat from Soviet and Chinese submarines, Neptunes of both 10 and 11 Squadrons provided continual escort, along with navy destroyers, from Townsville to Vung Tau in South Vietnam. To achieve continual cover the Neptunes were deployed from the Philippines, Singapore, Butterworth, and three flew between Lae in Papua New Guinea and Agana in Guam.
Number 11 Squadron would re-equip their P-2E fleet with P-3B Orions by 1968. Meanwhile, number 10 Squadron continued to operate the SP-2H for another decade, monitoring waters close to Australia during that Cold War period. The last operational flight was on the 30th of November, 1977, a fisheries surveillance sortie, before the fleet was retired, being replaced by the P-3B Orion.
