The Aérospatiale and Eurocopter (now Airbus Helicopters) collaborated to design and produce the Eurocopter AS350 Écureuil, also known as the Squirrel.
This single-engine light utility helicopter has now been rebranded as the Airbus Helicopters H125.
In the North American market, it is commonly referred to as the AStar.
During the early 1970s, Aérospatiale embarked on a development project aimed at creating a successor for the ageing Aérospatiale Alouette II.
Although the Aérospatiale Gazelle, which had been developed in the 1960s and 1970s, had received significant orders from military clients, its commercial sales fell short of expectations.
The new rotorcraft project, led by Chief Engineer René Mouille, prioritized creating an economical and efficient aerial vehicle.
Aérospatiale’s production and procurement departments played a significant role in the design process.
One key aspect was implementing a rolled sheet structure, inspired by the automotive industry, and introducing the innovative Starflex main rotor.
On June 27, 1974, the initial prototype, an AS350C with a Lycoming LTS101 turboshaft engine, completed its first flight in Marignane, France; the second prototype, equipped with a Turbomeca Arriel 1A engine, followed suit on February 14, 1975.
The AS350B, powered by the Arriel engine and designed for global sales excluding North America, received certification in France on October 27, 1977.
Meanwhile, the AS350C with the Lycoming engine was certified by the US Federal Aviation Administration on December 21, 1977.
Deliveries of the AS350B commenced in March 1978, while deliveries of the AS350C started in April 1978.
The AS350 Écureuil has undergone continuous development over the years, with enhancements made to the rotor system, powerplants, and avionics while maintaining a similar design.
A significant milestone was achieved on February 6, 1987, when a prototype AS350 flew with a fenestron tail-rotor instead of the traditional one.
Another milestone was reached on March 1, 1997, when the first AS350 B3, featuring an Arriel 2B engine, completed its maiden flight.
Third-party ‘aftermarket’ aerospace firms have developed conversion programs and addons for AS350s, in addition to the options provided by the prime manufacturer.
Variants of the Arriel-powered AS350B, AS350 BA, AS350 B1, AS350 B2, and AS350 B3 have been successively introduced, with the B3 model incorporating more digital systems like the Garmin-built G500H avionics suite and FADEC engine control system.
Prior to 2013, Eurocopter primarily manufactured the type at its Marignane facility in France.
However, in an effort to decentralise its helicopter production operations, Eurocopter decided to shift AS350 production and final assembly to its Columbus, Mississippi factory for the U.S. commercial helicopter market.
Variants
AS350
Prototype.
AS350 Firefighter
Firefighting version.
AS350B
Powered by one Turbomeca Arriel 1B engine.
AS350 B1
An improved version of the original AS350B, which is powered by one Arriel 1D engine, type also fitted with AS355 main rotor blades, AS355 tail rotor with tabs and a tail rotor servo.
AS350 B2
The higher-gross weight version is powered by one Arriel 1D1 engine over the B1 version, with an aerodynamic strake fitted to the tail boom along the starboard side and an angled engine exhaust duct for better yaw control.
AS350 B3
High-performance version is powered by an Arriel 2B engine equipped with a single channel Digital Engine Control Unit (DECU) with a mechanical backup system.
This helicopter is the first ever to land on the summit of Mount Everest.
AS350 B3/2B1
Variant introduces an enhanced engine with dual channel Full Authority Digital Engine Control (FADEC), dual hydraulics, and a 2,370 kg (5,225 lb) maximum take-off weight.
AS350 B3e
(introduced late 2011)
Equipped with the Arriel 2D engine; AS350 B3e renamed H125.
AS350 BA
Powered by an Arriel 1B engine and fitted with wider chord AS355 main rotor blades and tail rotor servo.
AS350 BB
AS350 B2 variant was selected to meet the rotary-wing training needs of the UK MoD through its Defence Helicopter Flying School in 1996.
Powered by a de-rated Arriel 1D1 engine to improve the helicopter’s life cycle.
Eurocopter Squirrel HT.1
The AS350BB operated by the British Military as a training helicopter.
Eurocopter Squirrel HT.2
The AS350BB operated by the British Army Air Corps as a training helicopter.
AS350 C
The initial variant of Lycoming LTS-101-600A2 powered version was developed for the North American market as the AStar.
Quickly superseded by AS350D.
AS350 D
Powered by one Lycoming LTS-101 engine for the North American market as the AStar.
At one stage marketed as AStar ‘Mark III.’
AS350 L1
A military derivative of AS350 B1, powered by a 510kW (684shp) Turbomeca Arriel 1D turboshaft engine.
Superseded by AS350 L2.
AS350 L2
A military derivative of AS350 B2, powered by a 546 kW (732shp) Turbomeca Arriel 1D1 turboshaft engine.
Designation superseded by AS550 C2.
HB350 B Esquilo
Unarmed military version for the Brazilian Air Force.
Brazilian designations CH-50 and TH-50. Built under licence by Helibras in Brazil.
HB350 B1 Esquilo
Unarmed military version for the Brazilian Navy.
Brazilian designation: UH-12.
Built under licence by Helibras in Brazil.
HB350 L1
Armed military version for the Brazilian Army.
Brazilian designation: HA-1.
Built under licence by Helibras in Brazil.
Specifications
Écureuil 1
Crew
1
Capacity
5
The 6-passenger configuration replaces the single passenger forward seat with a two-person bench seat.
Length
10.93 m (35 ft 10 in) (fuselage)
Height
3.145 m (10 ft 4 in)
Empty weight
1,174 kg (2,588 lb)
Max take-off weight
2,250 kg (4,960 lb)
Powerplant
1 × Turbomeca Arriel 2B turboshaft engine,
632 kW (848 hp)
Main rotor diameter
10.7 m (35 ft 1 in)
Main rotor area
89.75 m2 (966.1 sq ft)
Performance
Cruise speed
245 km/h (152 mph, 132 kn)
Never exceed speed
287 km/h (178 mph, 155 kn)
Range
662 km (411 mi, 357 nmi)
Endurance
4 hours, 6 minutes
Service ceiling
4,600 m (15,100 ft)
Rate of climb
8.5 m/s (1,670 ft/min)
Sources Helicopters: An Illustrated History of their Impact-S S McGowen. How the Helicopter Changed Modern Warfare-W Boyne. National Air and Space Museum of France.
