The FAA is changing their RVSM height monitoring flight requirements in conjunction with ICAO. Initial monitoring of all N-registered aircraft still must be completed within 6 months of issuance of the RVSM Letter of Authorization. After initial monitoring, and after May 18, 2011, operators must accomplish an RVSM height monitoring flight (via AGHME/HMU overflight or GMU flight) at least once every two years or within intervals of 1,000 flight hours per airplane, whichever period is longer. This new monitoring requirement goes into effect on May 18, 2011 and operators have until November 18, 2012 to comply. If an operator does not comply with the two year or 1,000 hour monitoring requirement, they risk suspension of their RVSM Letter of Authorization until a monitoring flight can be accomplished.