Here at the Singapore Airshow, Raytheon Missile Systems (Stand U01) is showcasing its Fish Hawk standoff antisubmarine torpedo.  While the weapon has been under development for some time, this is its inaugural promotion at a major international exhibition, highlighting the interest in it from the Asia-Pacific region.

Development of the Fish Hawk began in answer to the changing nature of antisubmarine warfare, with a greater emphasis being placed on operations against quiet submarines operating in littoral waters. The nature of ASW patrol aircraft operations is also changing as the U.S. Navy gears up to welcome the Boeing P-8 Poseidon into its ranks as a replacement for the P-3 Orion.

Under the high-altitude ASW weapon concept (HAAWC) program the U.S. Navy is looking for a torpedo that can be air-delivered from high altitude and standoff range. By removing the need to descend to low level in proximity to the submarine and inshore defenses, the ability to launch in the high-altitude regime enhances aircraft survivability, increases time on station and reduces stress on the airframe.

Rather than rig an existing wing/guidance kit to the Navy’s Mk 54 lightweight torpedo (also supplied by Raytheon), the company started from scratch in designing an all-new, low-profile pivot wing kit tailored to the P-8. Although it is aimed principally at the Poseidon, the Fish Hawk can also be carried by the P-3 and other maritime patrol aircraft as its streamlined form mirrors that of the standard Mk 54.
While the Fish Hawk is a new weapon, its modular nature allows the incorporation of proven guidance components, such as those gathered from the AGM-154 JSOW standoff weapon. This approach provides the all-new weapon with a healthy measure of system maturity and the ability to move swiftly to production if required.

According to Mark Borup, head of the Fish Hawk’s business development, “this maturity allows us to build it to requirement and to cost, with low risk.” It also enhances system reliability, he maintained.

The Fish Hawk’s modularity also allows a range of options to be incorporated to match customer requirements. A key option is the provision of a data link, which would allow the weapon to transmit health and status data in flight back to the control aircraft. Working in the opposite direction, the link allows updated or alternate target data to be fed to the weapon, mission abort signals to be sent, or control to be handed off to other platforms.

After release, the Fish Hawk pivots its wings to the spread position and glides by GPS/inertial guidance to either a pre-planned target location, or to a new point transmitted to the weapon via the link. Once descended to low level the wing kit is jettisoned and a chute is deployed to decelerate the torpedo for water entry. When in the water the Mk 54’s sonar and inertial systems take over. Although the weapon is designed to give standoff capability, it has a substantial launch envelope and can be released right above its target, employing a spiral pattern to descend rapidly.

The Fish Hawk was first tested on March 21, 2008, during a flight over the Gulf of Mexico from Eglin AFB, Florida. The trial exceeded all requirements and demonstrated a high level of accuracy, validating the weapon’s guidance algorithms.

Now Raytheon and its main competitor, Lockheed Martin (offering a proposal based on its Longshot wing kit), are waiting for the Navy to take the next step. “This requirement will most likely go forward,” said Borup, “and we are very comfortable with where we perceive the Navy to be going with this program. We offer the best standoff range, high off-boresight capability and a mature and cost-effective proposal. And it could be available quickly if needed.”