The EC 135 is a lightweight five/seven seat twin-turbine-engine multi-role helicopter with a radius of 720 km. The EC 135 is offered with either Turbomeca Arrius 2B2 or Pratt and Whitney Canada PW206B2 engines. Development of the Eurocopter EC135 started in the 80s as the MBB Bo.108 Advanced Technology Helicopter. The prototype BO108 with conventional tail rotor flew first on 15 October 1988. When the helicopter divisions of MBB from Germany and Aerospatiale from France merged in January 1992 to form the Eurocopter Group, the Bo108 program was transferred as well. An advanced low noise ducted 10-blade Fenestron tail rotor was, next to other modifications, incorporated into the design and the name of the helicopter was changed into Eurocopter EC135. The prototype of the EC135 (D-HBOX s/n S-01) flew first on 15 February 1994 and went into series production in 1996 at Donauwörth. After German certification was granted on 14 June 1996, on 31 July that year was the first customer delivery. Over 600 have been delivered since the helicopter entered service with the German rescue company DRF - Deutsche Rettungsflugwacht e.V. in 1996.

NAH (Notarzthubschrauber) EC135T1 OE-XEA "Christophorus 1" of the ÖAMTC Christophorus Flugrettungsverein was photographed at the helipad of the Heliair location at Innsbruck Airport in Austria that was opened on 22 May 2005. The "Christophorus 1" is based at Innsbruck Airport Kranebitten since 1 July 1983. The callsign "Christophorus" is used for the Austrian lifeliner helicopters since 1983 and is derived of Saint Christophorus, the Patron Saint for all travellers. This in 1997 built EC-135T1 was registered first D-HECK with Eurocopter Germany for test flying. On 26 August 1997, the D-HECK was delivered to Helicopter Air Transport GesmbH (heliair) and re-registered OE-XEA in August 1997. The OE-XEA was the first EC135 for Christophorus Flugrettungsverein and entered service at Innsbruck as "Christophorus 1" on 5 September 1997. The OE-XEA was registered with the Christophorus Flugrettungsverein in October 1997. After the EC135 was re-registered D-HECN in late 1997 it was registered OE-XEA again with the Christophorus Flugrettungsverein, Wien, in January 1998. In October 2007, the OE‑XEA was registered with Helkopter Air Transport, Innsbruck.