Question 22, Communication - PPL(A) English - Private Pilot License

Concerning aircraft and their passengers which face a grave and imminent threat and require immediate assistance.
Concerning the safety of an aircraft, a watercraft or some other vehicle or person in sight.
Concerning the operation or maintenance of facilities essential for the safety or regularity of aircraft operation.
Sent by a pilot or an aircraft operating agency which have an imminent meaning for aircraft in flight