Airlift support for the US Air Force Academy cadet parachuting program is provided by three UV-18B aircraft which carry a pilot, copilot and up to 17 jumpers. These Twin Otters are the only three owned by the Air Force. In the MSAG Antenna Test and Evaluation conducted 25-31 August 1998 in Marina CA, the NPS/CIRPAS UV-18A Twin Otter provided the surrogate UAV function during a test and evaluation of the MSAG ITT Antenna under development by the Joint Projects Office. Imagery from the Twin Otter was received by the multi- source capable antenna based at the CIRPAS facility in Marina. In the Alaska Army National Guard the UV-18As have been replaced by the C-23B+.
https://fas.org/man/dod-101/sys/ac/uv-18.htm
and:
Because the DeHavilland DHC-6 Twin Otter is a highly maneuverable aircraft which can be flown slowly (80-160 knots/150-300 km/hr) and in tight circles, these aircraft are considered extremely versatile survey airplanes....
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Thanks for the expanded data, Enigo54!
All credit to The Nerds, I only report what seems important!