Editing Eurocopter EC135 (section)

===Origins===
The H135 started development prior to the formation of Eurocopter, under [[Messerschmitt-Bölkow-Blohm]] (MBB) under the designation Bo 108 in the 1970s. MBB developed it in partnership with [[Aérospatiale]], the Bo 108 was initially intended to be a technology demonstrator, combining attributes of the successful [[MBB Bo 105]] with new advances and an aerodynamically streamlined design.<ref name="pope">Pope, Stephen. [http://www.flyingmag.com/aircraft/helicopters/eurocopter-ec-135 "Eurocopter EC 135"]. {{Webarchive|url=https://web.archive.org/web/20210420223830/https://www.flyingmag.com/aircraft/helicopters/eurocopter-ec-135/ |date=20 April 2021 }} ''Flying'', 18 May 2012.</ref><ref name="Benenson">Benenson, Tom. [https://books.google.com/books?id=3bYAtMRVj0cC&pg=PA86 "The EC135: Melding form & Function"]. ''Flying'', April 2004. Vol. 131, No. 4. pp.&nbsp;86–91.</ref> Technologies included on the Bo&nbsp;108 included the first full-authority digital engine controls ([[FADEC]]) on a helicopter, a hingeless main rotor, and the adoption of a new transmission.<ref name="pope"/> The first prototype made its first flight on 17 October 1988, powered by two [[Allison Engine Company|Allison]] [[Rolls-Royce Model 250|250-C20R]]/1 engines. A second Bo&nbsp;108 followed in June 1991, this time with two [[Turbomeca]] TM319-1B Arrius engines. Unlike later production aircraft, both technology demonstrators flew with conventional tail rotors.<ref name="autogenerated1"/>

[[File:MBB Bo 108.jpg|thumb|A Bo 108 prototype]]

In the late 1990s, the design was revised with the introduction of the ''[[Fenestron]]'' tail rotor system, an advanced rigid main rotor, composite materials, and resonance isolation systems.<ref name="pope"/> It was decided to pursue a full certification program, resulting in the production of two pre-production prototypes. At the same time, the Bo 108 was given a new designation of EC135, to correspond with the newly created Eurocopter company.<ref name="pope"/> At this point, it was decided that the EC135 should be developed with the option of being powered by two competing engines, the [[Turbomeca Arrius]] 2B and the [[Pratt & Whitney Canada PW206B]] engines. Two pre-production prototypes were built in 1994 powered by either engine, both powerplants proved to be successful and were used on subsequent production aircraft.<ref name="Benenson"/>

In January 1995, the EC135 made its first public appearance at the Heli-Expo convention at [[Las Vegas, Nevada|Las Vegas]], at which prospective buyers were reportedly impressed with its appearance and performance figures.<ref name="pope"/> Another feature which became apparent upon entering service was the low noise levels produced, in part due to its Fenestron tail, the EC135 was the quietest aircraft in its class for more than 15 years.<ref name="pope"/> Despite the helicopter's design being primarily oriented towards emergency medical operators, the EC135 had considerable appeal to a wide range of operators.<ref name="pope"/> European [[Joint Aviation Authorities|JAA]] certification was achieved in June 1996, with [[FAA]] approval following in July.<ref name="Benenson" />

In December 1999, the EC135 was granted single-pilot IFR (SPIFR) certification by Germany's [[Luftfahrt-Bundesamt]] (LBA). In December 2000, the United Kingdom's [[Civil Aviation Authority (United Kingdom)|Civil Aviation Authority]] also gave the EC135 SPIFR certification.<ref>Rimmer, David. [https://web.archive.org/web/20150531164954/http://connection.ebscohost.com/c/articles/3999599/ec-135-gains-single-pilot-certification "EC 135 Gains Single-Pilot Certification"]. ''Business & Commercial Aviation'', January 2001, Vol. 88 Issue 1. p. 17.</ref>