Visual Flight Rules require that pilots flying VFR must maintain visual contact with the ground at all times. This precludes flight above any cloud layer that constitutes a ceiling (i.e.: broken or overcast). In some cases this may prevent the completion of a VFR flight, despite the fact that prevailing weather at both the departure and destination aerodromes is VFR.
The VFR OTT rating may be added to the Canadian Private Pilot License and allows a rated pilot to transit above a broken or overcast layer provided that certain conditions are met. These conditions relate to the minimum weather requirements as well as essential equipment that must be carried and serviceable.
VFR-OTT does not permit flight into cloud, and must be conducted with reference to a visible horizon. However, navigation must be conducted without visual reference to the ground. Furthermore, there is an increased risk of inadvertent flight into Instrument Meteorological Conditions (IMC). Aviation Regulations (CARS) therefore specify that following requirements must be satisfied to obtain a VFR OTT Rating:
The instructor will then recommend the candidate for the rating.