A method for generating, in an aircraft in flight, a feasibility display indicative of the feasibility of a weapon carried on the aircraft successfully engaging a target and/or the feasibility of a weapon carried on the target successfully engaging the aircraft, the method comprising: providing, for use by one or more first processors (21, 25, 29, 33) remote from the aircraft, a generic test algorithm, the generic test algorithm specifying a set of multiple possible tests for testing feasibility data, the feasibility data being indicative of the feasibility of a weapon carried on the aircraft successfully engaging a target and/or the feasibility of a weapon carried on the target successfully engaging the aircraft; determining, by the one or more first processors (21, 25, 29, 33) remote from the aircraft, configuration data for configuring the generic test algorithm to specify one or more particular tests from the set of multiple possible tests; uploading the configuration data from the one or more first processors (21,25, 29, 33) to one or more second processors, the one or more second processors being on the aircraft; providing, for use by one or more second processors on the aircraft, the feasibility data; configuring, by the one or more second processors on the aircraft, the same generic test algorithm using the uploaded configuration data, thereby determining, on the aircraft, the one or more particular tests; modifying, by the one or more second processors on the aircraft, the feasibility data to satisfy the one or more particular tests, thereby generating modified feasibility data; and generating, by the one or more second processors on the aircraft, the feasibility display using the modified feasibility data. providing, for use by one or more first processors (21, 25, 29, 33) remote from the aircraft, a generic test algorithm, the generic test algorithm specifying a set of multiple possible tests for testing feasibility data, the feasibility data being indicative of the feasibility of a weapon carried on the aircraft successfully engaging a target and/or the feasibility of a weapon carried on the target successfully engaging the aircraft; determining, by the one or more first processors (21, 25, 29, 33) remote from the aircraft, configuration data for configuring the generic test algorithm to specify one or more particular tests from the set of multiple possible tests; uploading the configuration data from the one or more first processors (21,25, 29, 33) to one or more second processors, the one or more second processors being on the aircraft; providing, for use by one or more second processors on the aircraft, the feasibility data; configuring, by the one or more second processors on the aircraft, the same generic test algorithm using the uploaded configuration data, thereby determining, on the aircraft, the one or more particular tests; modifying, by the one or more second processors on the aircraft, the feasibility data to satisfy the one or more particular tests, thereby generating modified feasibility data; and generating, by the one or more second processors on the aircraft, the feasibility display using the modified feasibility data.