Flight information will be made available, whenever practicable, to any
aircraft in communication with an ATC unit, prior to takeoff or when in flight,
except where such service is provided by the aircraft operator. Many factors
(such as volume of traffic, controller workload, communications frequency
congestion and limitations of radar equipment) may prevent a controller from
providing this service. VFR flight will be provided with information
concerning severe weather conditions along the proposed route of flight, changes
in the serviceability of navigation aids, conditions of airports and associated
facilities, other items considered pertinent to safety of flight.
Canadian Glider Pilot Groundschool