It's a Shorts 330.
At first sight, similiar to the Shorts Skyvan, but a totally different plane. Bigger than the Skyvan, and uses different engines. The Skyvan uses Garrett TPE331 series engines, while the 330 and 360 use PWC PT6A series engines.
The 330 is a cargo/passenger plane with an aft cargo ramp , the 360 is basically a stretched 330 with a normal cruciform tail, and no cargo ramp.

More info and pics here: http://www.air-and-space.com/Shorts%...0330%20360.htm