Based on the EC 135, the Eurocopter EC 635 is a modern light utility helicopter used for military and civil purposes and which has replaced the older German Bo 105 which Eurocopter had maintained in production well into the 1990s. The EC 635 is essentially a twin-engined multi-role helicopter constructed extensively with composite material and crashworthy seats and fuel systems. It is also designed with the Eurocopter traditional Fenestron ducted-fan anti-torque tail rotor for much quieter and safer operation as well as a FADEC digital electronic control system for power management. These features allow for high operational efficiency as well as day or night all-weather capability in roles such utility and troop transport, reconnaissance, and search and rescue (SAR) although, like its predecessor, can also be equipped for light attack missions with cannon, rocket, and even missile loads. Current foreign operators are Jordan and Switzerland.
First flight of the civilian EC 135 (based on the Bo 105) was on 15 February 1994 with production commencing two years later. Military versions known as the EC 635 entered service early in the current decade and come in two different variants which differ only on their powerplant configuration. The EC 635 P1 features Pratt & Whitney 206B engines while the EC 635 T1 has slightly more poweful Turbomeca Arrius 2B1 engines, both FADEC-controlled. Performance figures are nearly identical with the EC 635 P1 having marginally greater range.