Eurocopter AS355 Écureuil 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
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.

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.

Twin engine



 * AS355
 * 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).


 * Powered by two Allison 250-C20F engines, 2,400 kg (5,291 lb) Maximum weight.
 * 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 Superseded by AS555 Fennec.


 * 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.
 * 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).


 * HB.355F Esquilo Bi
 * Assembled in Brazil by Helibras (part of Eurocopter).


 * HB.355N Esquilo Bi
 * Assembled in Brazil by Helibras.

Aftermarket conversions

 * 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.

Operators
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

 * Algerian Air Force
 * Argentine Naval Prefecture
 * Border Guard
 * Brazilian Air Force
 * Brazilian Navy
 * Royal Cambodian Air Force
 * Ontario Provincial Police
 * Djibouti Air Force
 * Jamaica Defence Force
 * 🇲🇼 Malawi
 * Malawi Air Wing
 * Royal Malaysia Police
 * Ontario Provincial Police
 * Djibouti Air Force
 * Jamaica Defence Force
 * 🇲🇼 Malawi
 * Malawi Air Wing
 * Royal Malaysia Police
 * Malawi Air Wing
 * Royal Malaysia Police
 * Royal Malaysia Police
 * New Zealand Police
 * Ministry of Interior
 * National Navy of Uruguay
 * Massachusetts State Police
 * National Navy of Uruguay
 * Massachusetts State Police
 * Massachusetts State Police
 * Massachusetts State Police

Former operators

 * Bophuthatswana
 * Bophuthatswana Air Force
 * Garda Air Support Unit
 * Garda Air Support Unit

Accidents and incidents

 * On 22 October 1996, Chelsea Football Club Vice chairman Matthew Harding together with five companions were killed when their AS355 F1 Squirrel, registration G-CFLT, crashed near Middlewich, Cheshire.
 * In July 1998, the Kent Air Ambulance, a 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. All three crew – the pilot, Graham Budden, and two paramedics, Tony Richardson and Mark Darby – were killed on impact.
 * 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..
 * On 18 August 2011, a AS-355F-2 (reg No/ VH-NTV) crashed near Lake Eyre in South Australia resulting in three fatalities. 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.
 * 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.
 * 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.