System and method for aircraft contaminant monitoring

An aircraft operation scheduling system includes a computing arrangement operable to compute a measure of contaminant exposure for estimating aircraft contamination. The computing arrangement receives schedule information for a plurality of flights and interrogates a database of contamination data as a function of location and time to derive an estimated historic contamination for the aircraft or each aircraft engine to at least one contaminant and an estimated expected contaminant exposure for the aircraft or engines. The computing arrangement is further operable to (i) identify at least one aircraft or engine with higher or lower estimated historical contamination, (ii) identify at least one route with higher or lower expected exposure to the at least one contaminant, and (iii) provide recommendations on route allocation by assigning an aircraft with the higher estimated historical contamination to a route with lower expected exposure to the contaminant. Preferably, route allocation recommendations ensure that an aircraft or engine's total exposure to contamination is maintained within a required range and/or aims to minimise variation in exposure across a fleet. The system may assign aircraft with lower estimated historical contamination to routes with higher expected exposure.