A Lufthansa Flight 429, enroute from Charlotte/Douglas Airport in US to Munich, Germany has turned around just off the Newfoundland Coast and is returning reportedly to Boston. Ambulances and police are standing by at Moncton, New Brunswick Airport, but aircraft is indicating it will divert to Boston. Aircraft currently over the Gulf of St. Lawrence just north of PEI and proceeding toward Boston. Operating on 133.550 mhz