Already for more than fifty years, the AS350 helicopter, now marketed as the Airbus H125, has been a sales success for Aérospatiale and its successors. Although the Gazelle was intended as replacement for the Alouette II, it was no success on the civil market. Hence, Aérospatiale designed the AS350, that was named Écureuil. The twin engined AS355 is also part of the family.

The AS350 is similar in size as for example the Bell 206 and the earlier Alouette III. The fuselage shape and window pattern is one of the key recognition points. The fuselage has not distinct nose; the cockpit front windows form a straight line to the nose. The fuselage is then curved from the nose, along the bottom to the root of the tail boom. The windows at the feet of the crew are also very typical for the Écureuil. The turboshaft engine is placed on top of the fuselage. It has an air intake at the front of the cowling, and an exhaust at the rear. The engine powers a three blade main rotor, of which the rotor blades are attached to the rotor mast by upper and lower blade. This is called the Starflex design. The covered tail boom is nothing special, perhaps except for the covered drive shaft on top and the highly swept vertical fin up. There is a two blade tail rotor at the end on the right. In front are plain horizontal stabilisers without end plates. The AS350 has skids as landing gear. 

The Écureuil is built under license in Brazil, United States and India.

The different versions of the AS350 and AS355 can be identified by looking at

• the number of engines
• the shape of the gear box/engine housing
• the shape of the exhaust(s)
• the presence of a long strake along the right side of the tail boom
• the size of the main and tail rotor blades

More details will follow later.