Newly acquired Boeing Chinook CH-47F heavy-lift helicopters supplied to the royal Netherlands air force are to be fitted with a state-of-the-art modular pod designed to protect it from missiles fired by hostile ground forces. Developed by Terma and building on its previous experience in protecting Apache helicopters in a similar way, the pod solution has been tailored to the needs of forces operating in the difficult environments found in Iraq and Afghanistan.

Dubbed the Chinook Aircraft Survivability Equipment (CHASE), the system comprises three missile sensors and one laser turret installed on each side of the helicopter. This not only provides a 360-degree spherical coverage but also a mechanical integration between the missile warning sensors and the Directed Infra-Red Countermeasures (DIRCM) produced by Northrop Grumman.

After initial flight tests to be conducted next month, Terma will provide CHASE as an integrated part of Boeing’s delivery of the new helicopters starting in 2008. The pods are mounted directly on to the helicopter main frame to minimize dynamic in-flight impact that can cause optical sensor distortion.

Alternative installations of sensors on the fuselage will need to deal with airframe twist, which can be significant during extreme maneuvers in the Chinook. This can cause misalignment between the sensors and the DIRCM system, which again can result in distortion of overall performance and an increasing number of false alarms.
Terma notes that CHASE can be installed with minimum downtime, while the possibility exists for sharing the units across a fleet of helicopters rather than install fixed aircraft survivability equipment assets to each individual aircraft.