EC155 gets new SAR mode

 - May 25, 2010, 11:24 AM

Eurocopter is offering on the EC155 Dauphin the autopilot search-and-rescue (SAR) mode that until now could be found only on the larger EC225 Super Puma. Certified earlier this year on the EC155, the SAR mode gives better stability and precision, particularly in environments where the former SAR mode was not operational.
“We can now perform auto hovers above a boat in rough seas,” Eurocopter’s director for military lift market development and avionics expert, Jérôme Combe, told AIN. Mainly using pressure altitude and two GPS receivers, the helicopter is no longer subject to the influence of swell. As a result, hoist operations in automatic mode have improved precision–three feet rather than 16 feet.

Previously, a Doppler radar was used in conjunction with a radio altimeter, but accuracy disruption by structures such as boats meant that with that system an approach with automated transition to hover and automatic hover could be performed only above a liferaft or a survivor. Using the new SAR mode on an EC225, a CHC Norway crew performed a rescue from above a 100-foot-long fishing vessel, in 25-foot waves, at night.

The new mode will also be useful for ground rescue, Combe said. When a rescue crew uses the hoist, it is because the site is too narrow to land, so the helicopter needs precision. Sometimes the pilots lacks visual reference to maintain a precise and stable hover, such as when the helicopter is flying over the top of a hill. In that case, auto hover can be used. This mode can also be used to hold the helicopter next to a cliff in turbulent air, Combe pointed out.