Monitoring height keeping performance is to estimate and evaluate the Altimetry System Error (ASE) of an aircraft operation in the Reduced Vertical Separation Minimum (RVSM) airspace. AEROTHAI provided the Readiness Assessment for Implementation of RVSM of ATC for Operation Service to airlines and freight forwarders in many countries, which are Bhutan, China, Hong Kong, India, Indonesia, Malaysia, Myanmar, Nepal, Pakistan, Singapore, Vietnam, and Thailand.

Monitoring Agency for Asia Region (MAAR) was established by AEROTHAI under the approval of the Asia/Pacific Air Navigation Planning and Implementation Regional Group (APANPIRG) to assume the duties and responsibilities of the Regional Monitoring Agency (RMA) for the Asia Region. 

The principal role of the MAAR is to assist the International Civil Aviation Organization (ICAO) in the continuation of the safety assessment program for the implementation of RVSM and other monitoring requirements as determined by the APANPIRG.