New technology from BAE Systems to help choppers evade small arms fire

BAE Systems has unveiled a new technology aimed at enabling helicopter pilots to detect and evade small arms fire. The acoustic-based Hostile Fire Indicator (HFI) is yet to become operational but the company appears to have made some progress.

A company video of the system in action shows a MD520 helicopter taking evasive action, presumably after detecting rounds fired within a few hundred feet from an AK-47 rifle.

BAE says: "In live-fire tests in the United States, an HFI system measured acoustic data and accurately detected threats in each test case. Further testing on military aircraft, using additional sensing technologies and techniques, will make the system more robust and improve its detection capabilities."

Even though a growing number of military helicopters now come equipped with infrared-based sensors to detect missile attacks, they still remain vulnerable to small arms fire.

The US Army began investigating acoustic-based sniper detection systems for helicopters in 2004, following a string of fatal attacks on helicopters in Afghanistan and Iraq.

Though companies such as Lockheed Martin and Northrop Grumman have shown interest in evolving solutions nothing effective has publicly emerged.

BAE has not clarified how far advanced its HFI technology is, or how soon it would make it available for induction. "Timing would depend on any future customer requirements," it says.

The company has acknowledged that filtering out background noise from the helicopter's rotor system remains HFI's biggest technical challenge.