Final answer:
Viscous hydroplaning occurs on smooth runway surfaces where a fine texture prevents water dispersion, creating a slippery layer that can lead to loss of control.
Step-by-step explanation:
Viscous hydroplaning is more likely on a smooth runway surface. When a layer of water on the runway cannot be dispersed, due to the surface texture being too fine, this can lead to viscous hydroplaning. This situation is most common when the water layer is over 1/10th of an inch and the aircraft is moving at a low speed. Adequate tread depth on aircraft tires and proper runway maintenance, including grooving the pavement, can help prevent this dangerous phenomenon.