Notification to aircraft owner/operators of a known safety issue with a particular model of aircraft, engine, avionics or other system. In the U.S.A are issued by the FAA and may be categorized as voluntary, mandatory or emergency
EESiFlo North America, Terminology and Glossary: Aviation Terms General Aviation, Pennsylvania, USA 2002. flowmeterdirectory.com/flowmeter_terminology, (Avn - Amer) {550}