EASA 2019-0269

Requires amendment of the aircraft flight manual to introduce additional limitations for operation within RVSM airspace and also modification of the airplane by installing improved air data computers (ADCs) and detachable configuration modules. Prompted by monitoring of P.180 Avanti II fleet by Eurocontrol that identified a mean altimetry system error and singular measurement exceedances outside of RVSM limits. Subsequent investigation determined that the static source error correction curves embedded in the pilot and copilot ADCs, as well as that in the standby instrument system, did not ensure the required RVSM performance of the airplane.