was destroyed in a mid-air collision in 1995. In service with Perimeter Aviation in Canada, this long-term operator of the Metro II and III made a number of modifications to suit its use in northern and remote Canadian sites where rudimentary gravel "strips" were common. Some of the many innovative changes to the design of the Metro allowed the aircraft to fly more efficiently, as well as cutting down on the "noise factor" that was attributed to the early models. The airline installed Garrett engines with quieter and more efficient four-bladed Hartzell propellers. More recently, in 2016, 5-blade composite propellers are being installed, further enhancing performance and reducing noise levels. Their Metros are also all equipped with modern avionics suites, including the recent installation of Garmin 950 glass cockpits and GPS satellite tracking. Many of the improvements resulting in the Metro 23 came about during work to produce the military C-26B model for the United States Air Force. A Metro III aircraft was modified for the Colombian Air Force for counternarcotics reconnaissance purposes. The Colombian National Police also operates several Metro 23 aircraft for counternarcotics reconnaissance purposes. In addition, the Peruvian Air Force operates a Metro 23 and the Trinidad and Tobago Coast Guard operates a Metro III, both similarly configured. A "Regional Security System" Metro III with a large belly radome has been seen in the Caribbean. In civilian service the type has proved to be popular, with sales in the 19-seat airliner market rivalled only by the Beechcraft 1900. It is especially popular in Australia. Since the first example (a Merlin IVA) arrived in 1975, almost 20% of the fleet has operated there, and, as of December 2008, 61 Metros and Expediters are registered in Australia, more than all of its market rivals combined. Metro production ended in 1998; however, by this time, regional jets were in vogue and turboprop types were out of favour with airlines. At the time, several airframes remained unsold at the factory. In 2001, the last aircraft, Metro 23 c/n DC-904B, was finally delivered to National Jet Aviation Services of Zelienople, Pennsylvania, an air charter operator. A total of 703 Metro, Expediter, Merlin IV series and C-26 series aircraft were built. In addition, 158 other SA226- and SA227-series aircraft were built as short-fuselage Merlin IIIs, IIIAs and IIIBs. Variants SA226 series SA226-TC Metro and Metro II - 198 built SA226-AT Merlin IVA -