The route is operated by SATA, the airline for the Açores. It is possible that there may be changes to the route following the recent liberalisation of commercial air services serving the islands, which is resulting in the restructuring of the airline.
SATA's current (January 2015) fleet equipment can be seen here: https://www.sata.pt/en/sata/fleet
A dummy reservation on the SATA web-site, shows that the route is operated by Bombardier(formerly De Havilland Canada) Q400 twin Turbo-Prop aircraft.
Tuesday, April 14, 2015
Departure: 08:55 Ponta Delgada Azores, Portugal - Joao Paulo II
Arrival: 13:50 Gran Canaria, Spain - Gran Canaria
SATA International S45502 e
Aircraft: De Havilland DHC-8 400 Series
More about the aircraft type here:
Photo By Aero Icarus from Zürich, Switzerland [CC BY-SA 2.0], via Wikimedia Commons