On October 21, 2014, at about 2005 universal coordinated time, a BAE Jetstream 41, registration HK-4503, operated by EasyFly S.A., experienced a No. 1 (left) engine stoppage during cruise after departing from Enrique Olaya Herrera Airport (EOH)- Medellin, Colombia. The flight crew declared an emergency and returned to EOH for an uneventful single engine landing. After landing a visual inspection of the No. 1 engine was performed and a hole was observed in the engine gearbox. The flight was a regularly scheduled flight from EOH to El Caraño Airport (UIB), Quibdó, Colombia. The investigation is being conducted by the Grupo de Investigación de Accidentes Aéreos (GRIAA) of Colombia. The NTSB has appointed an accredited representative to assist the GRIAA's investigation as the state of design of the airplane powerplants. All inquiries concerning this investigation should be directed to: Grupo Investigación de Accidentes Unidad Administrativa Especial de Aeronáutica Civil Aeropuerto Internacional Eldorado Avenida 26 No. 103 -23 Edificio CEA Oficina 204 Bogotá, D.C. Colombia Tel.: (57) 1 296-2138 / 2013 Tel.: (57) 1 296-2138 / 2013 (57) 317 517-1162 (mobile 24 hrs) (57) 317 517-1087 (mobile 24 hrs) E-mail: investigación.accide@aerocivil.gov.co Website:http://www.aerocivil.gov.co