Proteus Airlines Flight 706
In documentation published by the Aeronautical Information Service in 1997 and 1998 and probably used by the pilot of the Cessna, the use of a transponder while operating under visual flight rules could be interpreted as optional. As a result of the transponder being off, the Cessna was not depicted on the radar screen of the Lorient approach controller and its traffic information could not be relayed to the crew of the Beechcraft.