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.
Dummy Booking:
Tuesday, April 14, 2015
Departure: 08:55 Ponta Delgada Azores, Portugal - Joao Paulo II
Arrival: 13:50 Gran Canaria, Spain - Gran Canaria Airline:
SATA International S45502 e Aircraft: De Havilland DHC-8 400 Series
More about the aircraft type here: en.wikipedia.org/wiki/Bombardier_Dash_8

Photo By Aero Icarus from Zürich, Switzerland [CC BY-SA 2.0], via Wikimedia Commons