Eurocopter AS355 Écureuil 2
| Company type | Company (defunct) |
|---|---|
| Industry | Aerospace, Helicopter manufacturing |
| Founded | 1970s |
| Defunct | Error: All values must be integers (help) |
| Fate | Merged into Eurocopter |
| Successor | Eurocopter (later Airbus Helicopters) |
| Headquarters | Marignane , France |
Area served | Worldwide |
Key people | René Mouille (Chief Engineer) |
| Products | Helicopters (including AS355 Écureuil 2) |
The Eurocopter AS355 Écureuil 2, also known as the Twin Squirrel and later rebranded as Airbus Helicopters AS355, is a twin-engine light utility helicopter initially developed and produced by the French company Aérospatiale.
This model evolved from the single-engine AS350 Écureuil and completed its first flight on 28 September 1979. In North America, it was marketed under the name TwinStar. After Aérospatiale merged into the multinational Eurocopter group during the 1990s, manufacturing persisted under this new organization. Production ceased in 2016, shortly after Eurocopter transitioned to the Airbus Helicopters brand.
Design and development
In the early 1970s, Aérospatiale initiated a project aimed at replacing the outdated Aérospatiale Alouette II, targeting civil aviation markets where the military-oriented Aérospatiale Gazelle had not achieved significant commercial success.
Under the leadership of Chief Engineer René Mouille, development focused on cost-efficient production methods, incorporating automotive manufacturing techniques such as rolled sheet metal structures and pioneering the Starflex main rotor design. The program intended to produce both civil and military versions to satisfy defense requirements.
The initial prototype, an AS350C equipped with a Lycoming LTS101 turboshaft engine, conducted its maiden flight on 27 June 1974 in Marignane, France. A subsequent prototype powered by a Turbomeca Arriel engine followed in February 1975. The twin-engine AS355 variant made its first flight on 28 September 1979 and was marketed as Écureuil 2, Twin Squirrel, or TwinStar in North America.
Internationally, production was extended through Brazilian manufacturer Helibras, which assembled both AS350 and AS355 models under license from Eurocopter, integrating locally sourced components. During the 2000s, Eurocopter explored establishing an additional production facility for the AS355 in China to broaden market access.
Although Eurocopter introduced the newer Eurocopter EC130 in 2001, manufacturing of the AS350/355 series and their military derivatives—the AS550/555 Fennec—persisted. In 2007, Eurocopter launched the enhanced AS355 NP, designed for corporate transport and utility missions as a competitive response to Bell Helicopter's Bell 417.
Several aftermarket providers have developed upgrade packages for the AS350 family, including advanced digital avionics such as Garmin's G500H suite, which improve operational functionality.
In September 2015, Airbus Helicopters declared it would discontinue AS355 production to concentrate on models with higher sales volumes. Manufacturing continued through 2016 to complete outstanding orders. Meanwhile, production of the single-engine AS350 variants not only continued but expanded during this timeframe.
Variants
- AS355
- Prototype version of the twin-engine Écureuil 2 or Twin Squirrel
- AS355 E
- Initial production model featuring single hydraulic system, powered by two Allison 250-C20F turboshaft engines
- AS355 F
- Upgraded with dual hydraulic systems; maximum takeoff weight of 2,300 kg (5,070 lb)
- Equipped with two Allison 250-C20F engines; maximum takeoff weight increased to 2,400 kg (5,291 lb)
- AS355 F2
- Powered by two Allison 250-C20F engines; maximum takeoff weight raised to 2,540 kg (5,600 lb) and fitted with yaw compensation system
- AS355 M
- First armed variant based on AS355 F1
- AS355 M2
- Armed version derived from AS355 F2, later succeeded by AS555 Fennec
- Incorporates two Turbomeca Arrius 1A engines and FADEC system for enhanced maximum takeoff weight (2,600 kg/5,732 lb) and improved single-engine performance; includes tail rotor strake for better yaw control
- AS355 NP Ecureuil 2
- Introduced in 2007 featuring two Turbomeca Arrius 1A1 engines and main gearbox based on AS350 B3; maximum takeoff weight increased to 2,800 kg (6,173 lb)
- HB.355F Esquilo Bi
- Produced under license in Brazil by Helibras (a Eurocopter subsidiary); designated UH-13 by the Brazilian Navy, with cargo and VIP versions designated CH-55 and VH-55 by the Brazilian Air Force
- HB.355N Esquilo Bi
- Brazilian license-built version assembled by Helibras
Aftermarket modifications
- Heli-Lynx 355FX1
- Equipped with Allison C20F engine; certified by FAA, TC, and EASA
- Heli-Lynx 355FX2
- Powered by Allison C20F engine; holds FAA, TC, and EASA approvals
- Heli-Lynx 355FX2R
- Features Allison C20R engine; approved by FAA and TC
- Starflex AS355F1R
- AS355 F1 model fitted with Allison C20R engine; authorized by FAA, TC, and EASA
- Starflex AS355F2R
- AS355 F2 variant incorporating Allison C20R engine and enhanced tail rotor blades; certified by FAA, TC, and EASA
Operators
The AS355 Écureuil 2 is utilized by private individuals, corporate entities, helicopter charter services, flight training organizations, as well as various law enforcement and governmental bodies.
Military and government users
- Border Guard
- Ministry of Emergency Situations
Previous operators
Accidents and incidents
- On 8 May 1992, the Polair One helicopter operated by the Western Australian Police crashed during a landing attempt in Kelmscott, Western Australia. The aircraft was consumed by fire after impact due to a likely vortex ring state. The pilot and crew sustained minor injuries while two passengers were seriously hurt.
- On 22 October 1996, an AS355 F1 Squirrel (registration G-CFLT) crashed near Middlewich, England, resulting in the death of all five occupants including businessman and Chelsea F.C. vice chairman Matthew Harding. The UK's Air Accidents Investigation Branch determined the pilot was insufficiently qualified for adverse weather conditions and recommended prohibiting commercial VFR helicopter night operations.
- In July 1998, the AS355 F1 of the Kent Air Ambulance struck power lines near Burham, killing all three crew members while returning to Rochester Airport following an aborted mission.
- On 2 May 2007, Philip Carter, Chelsea FC Vice President and founder of training firm Carter and Carter, died in a crash involving his partially owned Twin Squirrel (G-BYPA) as it returned from a football match.
- On 18 August 2011, an AS-355F-2 (VH-NTV) operated by the Australian Broadcasting Corporation crashed close to Lake Eyre, South Australia. Three people onboard perished including ABC chief pilot Gary Ticehurst and journalist Paul Lockyer. This incident prompted stricter regulations on helicopter night flying in Australia.
- On 20 October 2011, a Belarus border patrol twin-engine Eurocopter crashed near the Lithuanian frontier, resulting in five fatalities including three members of a television crew.
- On 29 March 2017, a Eurocopter AS-355F-1 Ecureuil 2 vanished over Snowdonia National Park in Wales while en route from Luton to Dublin carrying five individuals.