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Mk54 HAAWC
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American maritime patrol aircraft currently carry torpedos as part of their armament, which serve as key weapons against enemy submarines. As any high-diver of cliff-jumper knows first hand, however, water can feel surprisingly solid after a long fall. Torpedos still have to be released from low altitude, typically 100 feet or less above the waves. Two recent developments, however, are making this approach less practical for the US military. One is tests of sub-launched anti-air missile systems, using modified short-range air-air missiles that do not require radar guidance. The other is its selection of the 737-based P-8A Poseidon as its next maritime patrol and surface surveillance aircraft. The P-8A can perform low swoops if necessary, but its airframe is really optimized for cruising at altitude.

As these trends developed, someone in the US military asked the logical next question:

P-3: Bermuda 1985
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“what if we could attack a JDAM-ER style glide kit with GPS guidance to a lightweight torpedo, launch from high altitude, then let the kit maneuver it into attack position and release it near sea level instead? Not only would this fit the P-8A’s strengths, it would also let us reduce airframe fatigue on the old P-3C fleet.”

Enter Lockheed’s Longshot, aka. the High Altitude ASW Weapons Concept (HAAWC).

The LongShot system is a low-cost, self-contained wing adaptor kit that can provide these capabilities to a range of existing air-to-surface munitions, including sea mines, gravity bombs, laser-guided bombs and cluster bomb dispensers. The system is self-contained and includes a flight control computer, a GPS-based navigation system, and power sources; range is up to 50 nautical miles. This makes the LongShot kit a potential competitor to Boeing’s JDAM-ER offerings.

GBU-87 WCMD-ER Test
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It’s a competitor with a major difference, however. LongShot does not require a MIL-STD-1760 interface, or even an electrical interface with the aircraft. This means LongShot offers instant GPS capability and compatibility to a wide range of aircraft that would not otherwise be capable of launching GPS-guided weapons, without requiring a costly and time-consuming process of re-wiring the aircraft and/or setting up a weapons interface with its onboard systems. Targeting information can be input via a laptop computer, or through an in-aircraft knee pad device that plugs into the aircraft intercom. The knee pad device establishes two-way communication with LongShot via the aircraft’s UHF radio.

This procedure is an inconvenience to a fighter pilot when compared to fully-integrated weapons, but it works excellently well on aircraft like the P-3C, P-8A, and other bombers or specialty aircraft that have multiple crew and more work space.

Lockheed Martin had already been developing this extended range kit for the WCMD GPS-guided cluster bomb, and leveraged the “Longshot” kit it picked up in the Leigh Aerosystems acquisition as a starting point. The HAAWC wing kit is attached to the torpedo by two metal bands. A device forces open the bands, enabling the wing kit to jettison normally from the torpedo. In actual operation, the wing kit jettisons when the torpedo reaches its normal launch altitude close to the surface of the water. At that point, the torpedo simply performs normally.

Contracts and Key Events

P-8A: oncoming
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May 29/07: Lockheed Martin reports success in a single point concept demonstration conducted at the Atlantic Undersea Test and Evaluation Center (AUTEC) in the Bahamas. A MK-54 HAWC torpedo was launched from the internal weapons bay of a P-3 Orion aircraft flying above 8,000 feet, navigated via GPS into position, then self-jettisoned as the fully functional MK-54 exercise torpedo successfully splashed down. Lockheed Martin release.

Sept 26/06: Lockheed Martin announces successful wind tunnel and wing separation tests of its High Altitude Anti-Submarine Warfare Weapons Concept (HAAWC) system, using the Lockheed Martin LongShot® Wing Adapter Kit on the MK-54 torpedo. In the wind tunnel test at the San Diego Air and Space Technology Center’s Low-Speed Wind Tunnel, HAAWC demonstrated expected performance that would enable the torpedo to be launched at cruising speeds, at the maximum desired range from the target.

Lockheed Martin is working under a 7-month, $3 million contract for the U.S. Navy to demonstrate delivery of the MK-54 lightweight torpedo from a P-3C aircraft operating at high altitudes (approximately 20,000 feet).

June 13/06: Lockheed Martin announces a 12-month, $3 million US Navy contract for its High Altitude Anti-Submarine Warfare Weapons Concept (HAAWC). The program will demonstrate delivery of the MK-54 lightweight torpedo from a P-3C aircraft operating at high altitudes (approximately 20,000) feet. The demonstration will include a high-altitude launch, where the HAAWC-equipped torpedo will glide to its normal launch altitude close to the surface, and then jettison the LongShot wings prior to water entry.

March 11/03: Lockheed Martin announces its acquisition of certain assets of Leigh Aerosystems in Carlsbad, CA. Terms of the sale were not disclosed. Privately held Leigh Aerosystems designs, tests and produces the LongShot Wing Kit that can be attached to existing “dumb” bombs to increase accuracy and range.

Lockheed’s release says that the kit will be adapted into Lockheed Martin’s $102 million Wind Corrected Munitions Dispenser, Extended Range (WCMD-ER) program to be used on CBU-87, -89, and -97 dispenser weapons. WCMD-ER is expected to go into production in 2005. The Air Force has requested 7,500 of these systems.

Additional Readings & Sources

• Lockheed Martin – Longshot

• DID (updated) – Team Torpedo: Raytheon Partners to Support MK48 and MK54 Requirements. Used as our central article for developments.

• Deagel – Mark 54

• Federation of American Scientists – MK-54 Lightweight Hybrid Torpedo

• Seapower Magazine (June 2005) – Boeing Eyes High-Flying Torpedo. For the P-8A Poseidon program. The 737-based P-8A is a capable aircraft, but isn’t well suited to flying just 100 feet above the waves.

• Undersea Warfare Magazine (Winter/Spring 2002) – Torpedoes and the Next Generation of Undersea Weapons