Question 139, Communication - Quiz SPL - Sailplane Pilot License

When a pilot has flown into cloud or fog unintentionally and therefore would like to request navigational assistance from a ground unit
When the traffic situation at an airport allows the transmission of information which does not need to be acknowledged by the ground station
When no radio communication can be established with the appropriate aeronautical station, but when evidence exists that transmissions are received at that ground unit
When a transmission containing important navigational or technical information is to be sent to several stations at the same time