This Hughes 500C (369HS), construction number: 105-0773S, was taken into service by the Landhelgisgælan (Icelandic Coast Guard Service) on 7th April 1976. It was fitted with floats and its main role was to provide light transport duties and support to the Coast Guard Cutters. After crash-landing near Búrfell Hydropower station located in the Þjórsádalur valley on 17th November 1980 it was repaired and withdrawn from service. The Hughes 500C was sold to a buyer in the USA and replaced by a Hughes 500D with same registration, which itself was withdrawn in early 1986 and replaced by a Eurocopter AS.350B Ecureuil. 
The Aviation database  provides this additional information:
On 10th November 1998 it was subject of a new ‘N’ number assignment to N2644, the pending registration was for a private individual in Pleasant Hill, Oregon USA.
On 5th May 2004 the ‘N’ number assignment and registration was recorded with the details of Trafficopters Inc. based in Okeechobee, Florida. It shows the Hughes as being fitted with an Allison 250-c20 SER turbo-shaft engine.
On 14th June 2004 Trafficopters Inc. notified ‘N’ number assignment and registration as N500RT. On 29th August 2007 sale was notified showing details of a private individual with a contact details of MRI Centre Barringtons Hospital, County Limerick, Ireland. An image of this Hughes showing this registration was taken off airport at Newmarket-on-Fergus, Ireland on 21st August 2008, painted blue with white trim . The image may be viewed here.
On 31st October 2007 the ‘N’ number was assigned and registered to Southern Aircraft Consultancy Inc. Cornwall, United Kingdom and again to them on 16th September 2010 in Dereham, Norfolk. Sale was notified on 15th November 2011 showing details of a private individual in Dochgate, Ireland. On 9th January 2012 a second notice for registration renewal records the registrant as Avant Media Group Inc, Navarre, Florida USA.
Images © BBC Scotland, © Baldur Sveinsson 5th July 1977 Reykjavík RKV/BIRK
1. Aeroflight (2011). Hughes 500 [online]. URL [Accessed Dec. 25th 2014]
2. Aviation Database (2012). N Number 500RT [online]. URL [Accessed Dec. 25th 2014]
3. Airliners.net (2009). Hughes 500 (369HS) [online]. URL [Accessed Dec. 25th 2014]