text: Development Originally designated AS365 N4, the EC155 was developed from the Eurocopter AS365 N3 Dauphin 2 with the aim of significantly increasing the cabin space of the Dauphin. Development began in September 1996 with the helicopter officially announced by Eurocopter at the Paris Air Show in June 1997. The first EC155 helicopter, a modified Dauphin airframe, made its maiden flight at Marignane on 17 June 1997 and the first pre-production EC155 B flew on 11 March 1998. The aircraft received safety certification by the French and German civil aviation authorities on 11 December 1998 and went into production soon after, with a price tag of US$7–8 million depending on installed equipment.
  In March 1999, deliveries of the EC155 B commenced, the German Federal Police became the first operator of the type. Between March 1999 and June 2003, roughly 50 EC155 Dauphins were sold, mainly to VIP and off-shore customers.
  The EC155 B1 was developed with uprated engines, giving it improved performance at high altitude and in hot temperature conditions; this derivative also features a higher maximum take-off weight (10,846 lb vs. 10,580 lb). Deliveries of this model began in November 2002 with the Hong Kong Government Flying Service becoming the first operator. In early 2003, Eurocopter completed studies for an even more powerful version of the EC155 B1, designed to better compete with new rotorcraft such as the AgustaWestland AW139 and to better meet military customer's requirements.
  Several major elements of the EC155, such its rotor system (albeit modified to operate at slower rotational speeds), were used in the Eurocopter X3, an experimental high-speed compound helicopter which set an unofficial speed record of  in 2013. In 2015, an EC155 was also used by Airbus Helicopters as a flying testbed for new aerodynamic features, such as the rotor blades, biplane stabilizer and canted fenestron, for the developing Airbus Helicopters H160 helicopter.