In the late 1970s, Aerospatiale introduced the AS350B as a replacement for the company’s Alouette II helicopter. Named Ecureuil (Squirrel) it used a Turbomeca Arriel 1B engine rated at 641 shp. For the U.S. market Aerospatiale gave it the name AStar and the model number AS350C. Both models had a maximum gross weight of 4,300 pounds, however, the C model used the Lycoming LTS 101-600A engine rated at 592 shaft horsepower (shp) for takeoff. Six months later the helicopter was upgraded to the D model with the installation of the Lycoming LTS 101-600A-2 engine, boosting its takeoff rating to 615 shp.
In 1987, Aerospatiale discontinued the D model and upgraded the B to a B1. This new version had a more powerful Arriel 1D (684 shp) engine and a higher gross weight of 4,850 pounds. The rotor system was upgraded with larger (more inertia) asymmetrical rotor blades and rotor rpm was increased slightly. This resulted in increased performance and better autorotation characteristics. The company also produced the BA model that had the larger blades, but retained the B model’s Arriel 1B engine. Three years later the B1 was replaced with the B2, using a more powerful Arriel 1D1 (712 shp) engine and gross weight jumped to 4,961 pounds. The B2’s cruise speed at MCP (maximum continuous power) is 133 knots. In 1992, Aerospatiale merged with MBB to form Eurocopter.
In the late 1990s Eurocopter introduced the B3, a high altitude version. It was powered by an Arriel 2B engine equipped with a single channel DECU (Digital Engine Control Unit) with a mechanical backup system. Although the gross weight remained the same, take off power increased to 747 shp. This was followed by a variant using the 2B1 engine with a dual channel FADEC (Full Authority Digital Engine Control). This version had a dual hydraulic system available as an option which when combined with high skid gear allows a gross weight increase to 5,225 pounds. The latest version, B3e, was introduced in late 2011 and is outfitted with a dual channel FADEC equipped Arriel 2D engine. Take off power rating jumped to 847 shp boosting its MCP cruise speed up to 137 knots and adding extra lifting capability.