Airborne geophysical surveys aid geological mapping by rapidly measuring physical properties of underlying bedrock and surficial materials over vast areas. Starting in the 1960s, the Geological Survey of Canada’s Magnetic Methods Group and Radiation Geophysics Section were tasked with developing instrumentation and methodologies to improve airborne magnetic and airborne gamma-ray spectrometry (AGRS) surveying.
To accomplish their research goals, the groups acquired two aircraft: a light twin-engine Beechcraft B80 Queenair aircraft for magnetics, and a twin-engine turboprop Skyvan for gamma-ray spectrometry.
Magnetic survey developments tested on the Queenair included digital data acquisition, improved active compensation systems, and vertical gradient techniques. The Skyvan anchored the Survey’s efforts to design and build in-house at least two generations of AGRS systems, and to develop a set of survey specifications for AGRS that became an industry standard and were adopted worldwide.
The Queenair flew 65 test and production magnetic surveys and the Skyvan flew approximately 175 AGRS surveys, before both were retired during the 1980s.