Despite the fact that production ceased in 1967, hundreds of Beavers are still flying—many of them heavily modified to adapt to changes in technology and needs. Kenmore Air of Kenmore, Washington provides Beaver and Otter airframes with zero-hour fatigue-life ratings, and owns dozens of supplemental type certificates (STCs) for aircraft modifications. These modifications are so well known and desirable in the aviation community, rebuilt Beavers are often called "Kenmore Beavers" or listed as having "Kenmore mods" installed. The original Wasp Jr radial engine of the Beaver is long out of production, so repair parts are getting harder to find. Some aircraft conversion stations have addressed this problem by replacing the piston engine with a turboprop engine such as the PT6. The added power and lighter installed weight, together with greater availability of kerosene fuel instead of high-octane aviation gasoline, make this a desirable modification, but at a high financial cost. The Beaver was deployed by the British Army Air Corps during the Troubles at least until 1979 for photo-reconnaissance missions. One of them was hit seven times by machine gun fire in South County Armagh, near the border with the Republic of Ireland in November 1979, while taking valuable photos of an IRA checkpoint. The border crossing where the action took place was known by the British Army as "Beaver Junction" since then. Operators of significant numbers of piston-Beavers in early 2008 include Air Saguenay and Harbour Air in Canada and Kenmore Air in the USA. Harrison Ford owns a DHC-2 Beaver and has called it his favourite among his entire fleet of private aircraft. The United States military continues to operate two DHC-2s at the United States Naval Test Pilot School, where they are used to instruct students in the evaluation of lateral-directional flying qualities and to tow gliders. The DHC-2 Beaver is sometimes used by skydiving operators due to its good climb rate.