The DeHavilland Twin Otter (DHC-6) is a highly maneuverable, versatile aircraft which can be flown slowly (80-160 knots/150-300 km/hr) and in tight circles. The Twin Otter is a high-winged,
... unpressurized, twin-engine turboprop aircraft equipped with color weather radar, radar altimeter, dual GPS/Loran-C navigation systems with scientific data drops, and camera ports in the nose and belly areas. A standard flight crew consists of two NOAA pilots. In support of NOAA or NOAA-related missions, this platform has conducted low-level slow speed aerial surveys of marine mammals, aerial video surveys of coastal erosion, various remote sensing missions, atmospheric air chemistry sampling, and atmospheric eddy flux and concentration gradient assessments.
[Photo and text provided by NOAA,
http://www.aoc.noaa.gov/aircraft_otter.htm ] 
