Eurocopter AS355 Écureuil 2

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AS355 Écureuil 2/Twin Squirrel/TwinStar
Aérospatiale AS-355 F2 Ecureuil 2 Héli Béarn SARL F-HJLD - MSN 5064 (5387445580).jpg
An AS355 departs Toulouse–Blagnac Airport
Role Light utility helicopter
National origin France
Manufacturer Aérospatiale
Airbus Helicopters
First flight 28 September 1979
Status In service
Produced 1975–present
Developed from Eurocopter AS350 Écureuil
Developed into Eurocopter AS555 Fennec 2

The Eurocopter (now Airbus Helicopters) AS355 Écureuil 2 (or Twin Squirrel) is a twin-engine light utility helicopter originally manufactured by Aérospatiale in France (later part of Eurocopter Group, now Airbus Helicopters). The AS355 is marketed in North America as the TwinStar.

Design and development[edit]

Development at Aérospatiale began in the early 1970s to replace the Aérospatiale Alouette II, and the first flight took place on 27 June 1974. A twin-engined version, known as the Écureuil 2, Twin Squirrel, or in North America as the TwinStar, first flew on 28 September 1979.[1]

Despite the introduction of the Eurocopter EC130 in 2001, production of both the AS350 and AS355, and of their AS550 and AS555 Fennec militarized counterparts, was continued for some time. In 2007, the more capable AS355 NP variant with FADEC engines was introduced to service. In September 2015, Airbus Helicopters announced that it was to terminate the manufacture of the AS355 as part of an effort to focus on stronger-selling rotorcraft – production of the AS350 is to continue. Production of the AS355 is to continue through 2016 until the existing order backlog is fulfilled.[2]


Twin engine[edit]

AS355N Twin Squirrel
AS355 Ecureuil 2
Prototype of the twin-engined Écureuil 2 or Twin Squirrel.
AS355 E
Initial production version, with single hydraulics, powered by two Allison 250-C20F turboshaft engines.
AS355 F
Improved version, with dual hydraulics and increased maximum weight of 2,300 kg (5,070 lb).
AS355 F1
Powered by two Allison 250-C20F engines, 2,400 kg (5,291 lb) Maximum weight.
AS355 F2
Powered by two Allison 250-C20F engines, 2,540 kg (5,600 lb) Maximum weight and a yaw compensation system.
AS355 M
Initial armed version of AS355 F1.
AS355 M2
Armed version of AS355 F2. Superseded by AS555 Fennec.
AS355 N Ecureuil 2
Version fitted with two Turbomeca Arrius 1A engines and a Full Authority Digital Engine Control (FADEC) system for better M.T.O.W (2,600 kg or 5,732 lb) and better single engine performance, tail rotor strake added along starboard side of tail boom for better yaw authority.
AS355 NP Ecureuil 2
Introduced in 2007, this version is fitted with two Turbomeca Arrius 1A1 turboshaft engines and a new AS350 B3-based main gearbox, increasing maximum take-off weight to 2,800 kg (6,173 lb).[3]
HB.355F Esquilo Bi
Assembled in Brazil by Helibras (part of Eurocopter).
HB.355N Esquilo Bi
Assembled in Brazil by Helibras.

Aftermarket conversions[edit]

Heli-Lynx 355FX1
Powered by the Allison C20F engine. FAA, TC, and EASA approved.
Heli-Lynx 355FX2
Powered by the Allison C20F engine. FAA,TC and EASA approved.
Heli-Lynx 355FX2R
Powered by the Allison C20R engine. FAA and TC approved.
Starflex AS355F1R
AS355 F1 powered by the Allison C20R engine. FAA, TC and EASA approved.
Starflex AS355F2R
AS355 F2 Powered by the Allison C20R engine with optimised tail rotor blades. FAA, TC and EASA approved.


The AS355 Écureuil 2 is used by both private individuals and companies, helicopter charter and training organizations as well as law enforcement and government use.

Military and government operators[edit]

 New Zealand
 United States

Former operators[edit]


Accidents and incidents[edit]

  • On 8 May 1992, the Western Australian Police Polair One helicopter crashed while attempting to land on a sports oval for a public display in Kelmscott. The helicopter was destroyed after a fire started in the engine bay following ground impact. The Bureau of Air Safety Investigation report determined "The helicopter probably entered a vortex ring state during the final approach". The pilot and crewman received minor injuries, and the two passengers serious injuries, as a result of the accident.
  • On 22 October 1996, an AS355 F1 Squirrel, registration G-CFLT, crashed in bad weather near Middlewich, Cheshire, England, killing all five on board. The people on board included Matthew Harding, a businessman and vice chairman of English football club Chelsea F.C. (the flight was returning to London from a Chelsea match in Bolton). The UK's Air Accidents Investigation Branch found that the pilot had insufficient qualifications and experience to fly in such poor conditions.[18][19]
  • In July 1998, the Kent Air Ambulance, an AS355 F1 Squirrel, crashed in good weather after colliding with power cables near Burham whilst returning to Rochester Airport following an aborted call to attend a road accident.[20] All three crew – the pilot, Graham Budden, and two paramedics, Tony Richardson and Mark Darby – were killed on impact.[21]
  • In May 2007, Chelsea Football Club Vice President Philip Carter, founder of training company Carter and Carter, crashed in his part-owned Twin Squirrel registration G-BYPA returning from Liverpool John Lennon Airport after watching Chelsea play Liverpool F.C..[22]
VH-NTV in December 2010
  • On 18 August 2011, an AS-355F-2 (reg No/ VH-NTV) crashed near Lake Eyre in South Australia resulting in three fatalities.[23] The helicopter was owned by the Australian Broadcasting Corporation. On board were, Gary Ticehurst (ABC chief helicopter pilot for 25 years), John Bean (cameraman) and Paul Lockyer (journalist). All three had 20 years or more experience working for the ABC.[24]
  • On 20 October 2011, a Belarus border patrol Eurocopter twin-engine helicopter crashed close to the village of Vileity near the Lithuanian border and burst into flames, killing all five people on board, including three members of a television crew.[25]
  • On 29 March 2017, a Eurocopter AS-355F-1 Ecureuil 2 was lost over the Snowdonia National Park in Wales whilst en route from Luton to Dublin, carrying five people on board.[26]

Specifications (AS355F2)[edit]

Cockpit of AS355 F1 Ecureuil 2

Data from Jane's All The World's Aircraft 1988–89[27]

General characteristics

  • Crew: 1
  • Capacity: 6 /
  • Length: 12.94 m (42 ft 5 in) inc. main and tail rotors
10.93 m (36 ft) fuselage and tail rotor only
  • Height: 3.14 m (10 ft 4 in)
  • Empty weight: 1,305 kg (2,877 lb)
  • Max takeoff weight: 2,540 kg (5,600 lb) internal load
2,600 kg (5,732 lb) with max. slung load
  • Fuel capacity: 730 l (190 US gal; 160 imp gal) usable, in two tanks
  • Powerplant: 2 × Allison 250-C20F turboshaft engines, 313 kW (420 hp) each
  • Main rotor diameter: 10.69 m (35 ft 1 in)
  • Main rotor area: 89.75 m2 (966.1 sq ft)
  • Blade aerofoil section: ONERA OA211 : root ; ONERA OA209/OA207 : tip[28]


  • Cruise speed: 224 km/h (139 mph, 121 kn) (max cruise)
  • Never exceed speed: 278 km/h (173 mph, 150 kn)
  • Range: 703 km (437 mi, 380 nmi) with max fuel no reserve
  • Service ceiling: 3,400 m (11,200 ft)
  • Rate of climb: 6.5 m/s (1,280 ft/min)

See also[edit]

Related development

Aircraft of comparable role, configuration and era

Related lists


  1. ^ Taylor 1988, p.61.
  2. ^ Perry, Dominic. "Airbus Helicopters ditches AS355 light twin." Archived 5 September 2015 at the Wayback Machine Flight International, 4 September 2015.
  3. ^ Eurocopter Press Release – Eurocopter Upgrades Its Most Affordable Twin, The AS355 Ecureuil/TwinStar Archived 23 December 2008 at the Wayback Machine
  4. ^ a b c d e f g "World Air Forces 2016". Flightglobal Insight. 2016. Archived from the original on 19 January 2016. Retrieved 28 May 2016.
  5. ^ "Argentine Coast Guard Receives its First Ecureuil". Air International. Vol. 80 no. 3. March 2011. p. 28. ISSN 0306-5634.
  6. ^ "Austrian Federal Ministry of Internal Affairs". Archived from the original on 5 September 2018. Retrieved 5 September 2018.
  7. ^ "Государственный пограничный комитет вооружается европейскими вертолетами". Archived from the original on 17 May 2013. Retrieved 1 March 2013.
  8. ^ "Парк воздушных судов". Archived from the original on 13 October 2018. Retrieved 13 October 2018.
  9. ^ "Ontario Provincial Police upgrade from AS355F2 to EC135P2+". Archived from the original on 4 June 2013. Retrieved 1 March 2013.
  10. ^ "Ontario Provincial Police AS-355F". Demand media. Archived from the original on 4 March 2016. Retrieved 1 March 2013.
  11. ^ "JDF AS-355". Archived from the original on 24 December 2013. Retrieved 1 March 2013.
  12. ^ "Royal Malaysian Police wants more helicopters". Archived from the original on 3 June 2013. Retrieved 1 March 2013.
  13. ^ "NZ Civil Aircraft". nzcivair .com. Archived from the original on 4 March 2016. Retrieved 1 March 2013.
  14. ^ "Russian Military Plans to Buy Foreign Helicopters". Archived from the original on 18 May 2013. Retrieved 1 March 2013.
  15. ^ "AS355 NP Overview". Archived from the original on 19 September 2012. Retrieved 1 March 2013.
  16. ^ "World's Air Forces 1987 pg. 28". Archived from the original on 16 May 2013. Retrieved 1 March 2013.
  17. ^ "About the Air Support Unit". Archived from the original on 22 February 2012. Retrieved 1 March 2013.
  18. ^ "Pilot disorientated on impact". BBC News. Retrieved 17 September 2007.
  19. ^ "Aircraft Accident Report 4/97" (PDF). Retrieved 7 December 2019.
  20. ^ "Bulletin No:2/2000 Aerospatiale AS355 F1 Ecureuil II G-MASK" (PDF). Air Accident Investigation Board. Archived from the original (PDF) on 17 March 2009. Retrieved 14 May 2009.
  21. ^ "UK Helicopter crash kills three". BBC News. 27 July 1998. Retrieved 4 January 2010.
  22. ^ "Millionaire Chelsea fan and his son die in helicopter crash". Daily Mail. 2 May 2007. Archived from the original on 21 December 2009. Retrieved 15 August 2010.
  23. ^ "Collision with terrain – Aérospatiale Industries helicopter, VH-NTV, near Lake Eyre, SA, 18 August 2011". Australian Transport Safety Bureau. 19 August 2011. Archived from the original on 21 August 2011. Retrieved 20 August 2011.
  24. ^ "ABC chopper crash probe could take a year". ABC News. Australian Broadcasting Corporation. 19 August 2011. Archived from the original on 20 August 2011. Retrieved 20 August 2011.
  25. ^ Helicopter crash in Belarus kills 5[permanent dead link]
  26. ^ "Missing helicopter: Police launch Snowdonia ground search". BBC News. Retrieved 22 June 2018.
  27. ^ Taylor, John W.R., ed. (1988). Jane's All the World's Aircraft 1988–89 (79th ed.). London: Jane's Information Group. pp. 60–62. ISBN 0-7106-0867-5.
  28. ^ Lednicer, David. "The Incomplete Guide to Airfoil Usage". Retrieved 16 April 2019.

Further reading[edit]

External links[edit]