The Citation Airbourne Field Mill system includes a complement of mills. The two starboard side mills are shown with the Cloud Particle Imager located below. The aft down mill is not shown in the photos.
The area around each flush-mounted mill has had the white paint replaced with black conductive paint. This reduces the interference due to the slow relaxation of electrical charging of the insulating painted surface.
The electric field mills used on the UND Citation incorporate dual 16-bit digitizers to achieve a measurement range of +/-2 v/m to 1.1 Megavolts/m.