The Eurocopter 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 at Donauwörth in 1996. After German certification was granted on 14 June 1996, was the first customer delivery on 31 July that year. Over 600 have been delivered since the helicopter entered service in 1996 with the German rescue company DRF - Deutsche Rettungsflugwacht e.V.

RTH (Rettungstransporthubschrauber) EC135P1 D-HSOS "Christoph Europa 2" was photographed during the 74th Dutch TT at the helipad of the "Circuit van Drenthe" near Assen in the Netherlands. The D-HSOS was operated as the HEMS-helicopter during the Dutch TT from 23- 26 June 2004. The D-HSOS "Christoph Europa 2" is stationed at the ADAC-Luftrettungszentrum Rheine located near the "Mathias-Hospital" in Rheine in Germany. The call sign "Christoph" is used for the German lifeliner helicopters since 1970 and is derived of Saint Christophorus, the Patron Saint for all travellers. The 1998-built EC-135P1 was registered D-HSOS with ADAC Luftrettung GmbH in September 1998.