A system for generating, in a first aircraft in flight, a display indicative of the feasibility of a weapon carried on the first aircraft or a second aircraft successfully engaging the other aircraft, the system comprising: a first generator configured for generating a database describing a performance envelope of the weapon; a second generator configured for creating coefficients characteristic of that performance envelope using a generic algorithm, wherein the generic algorithm has the form of a polynomial, by a) generating candidate polynomials the variables of the polynomials being some or all of a group of weapon or aircraft firing condition parameters, b) for each candidate polynomial, computing coefficients for that candidate polynomial which best fit that candidate polynomial to a characteristic of the performance envelope of the weapon using a criterion of least square error, c) for each candidate polynomial, generating a candidate score according to the quality of the fit of that candidate polynomial to the characteristic of the performance envelope of the weapon, d) applying a genetic algorithm to the candidate polynomials and scores including selecting the best scoring polynomials and discarding the other polynomial(s), thereby identifying a best candidate polynomial and coefficient set, and e) repeating said identifying process until all the required characteristics of the performance envelope have corresponding polynomial models; an uploader configured for uploading the coefficients to the first aircraft; and a reconstructor on the first aircraft containing the same generic algorithm and configured to select the coefficients for the generic algorithm according to conditions of both aircraft (1, T) and, using the selected coefficients, generate the feasibility display. a first generator configured for generating a database describing a performance envelope of the weapon; a second generator configured for creating coefficients characteristic of that performance envelope using a generic algorithm, wherein the generic algorithm has the form of a polynomial, by a) generating candidate polynomials the variables of the polynomials being some or all of a group of weapon or aircraft firing condition parameters, b) for each candidate polynomial, computing coefficients for that candidate polynomial which best fit that candidate polynomial to a characteristic of the performance envelope of the weapon using a criterion of least square error, c) for each candidate polynomial, generating a candidate score according to the quality of the fit of that candidate polynomial to the characteristic of the performance envelope of the weapon, d) applying a genetic algorithm to the candidate polynomials and scores including selecting the best scoring polynomials and discarding the other polynomial(s), thereby identifying a best candidate polynomial and coefficient set, and e) repeating said identifying process until all the required characteristics of the performance envelope have corresponding polynomial models; a) generating candidate polynomials the variables of the polynomials being some or all of a group of weapon or aircraft firing condition parameters, b) for each candidate polynomial, computing coefficients for that candidate polynomial which best fit that candidate polynomial to a characteristic of the performance envelope of the weapon using a criterion of least square error, c) for each candidate polynomial, generating a candidate score according to the quality of the fit of that candidate polynomial to the characteristic of the performance envelope of the weapon, d) applying a genetic algorithm to the candidate polynomials and scores including selecting the best scoring polynomials and discarding the other polynomial(s), thereby identifying a best candidate polynomial and coefficient set, and e) repeating said identifying process until all the required characteristics of the performance envelope have corresponding polynomial models; an uploader configured for uploading the coefficients to the first aircraft; and a reconstructor on the first aircraft containing the same generic algorithm and configured to select the coefficients for the generic algorithm according to conditions of both aircraft (1, T) and, using the selected coefficients, generate the feasibility display.