Patent ID: 6937924

Claim:
A method for analyzing aircraft flight data, the method comprising: (i) receiving flight data for measurements of each of P selected parameters {m(t;k;q)} (k=1, . . . , P) at each of N selected times (t=t n ) (n=n0, . . . , n0+N−1; N≧2) for one or more selected flights (q) of one or more aircraft; (ii) for each continuous-valued parameter p(t;k1) of each flight, numbered k1=1, . . . , K1 (K1≧0), and for a selected sequence of the times t=t n (n=n 0 , n0+1, . . . , n=n0+N− 1 , providing a polynomial approximation p(t;k1; app)=a (t n0 ;k1)+b (t n0 ;k1)·(t−t n0 )+c(t n0 ;k1).(t−t n0 ) 2 +e ( t n0 ;k1), where e(t n0 ;k1) is an error term, whose sum of the squares d(t n0 ;k1)=(N−3) −1 *Σe(t n ;k1) 2 , is minimized by the choice of the terms a(t n0 ;k1), b (t n0 ;k1) and c(t n0 ;k1); (iii) forming vectors A={a(t n0 ;k1)} n0 , B={b(t n0 ;k1)} n0 ,C={c(t n0 ;k1)} n0 , and D={d(t n0 ;k1)} n0 , forming an M1×1 vector E1 including a first order statistic m1(v), a second order statistic m2(v), a minimum value min(v) and a maximum value max(v) for each of the vectors v=A, v=B, v=C and v=D; (iv) for each discrete-valued parameter, numbered k2=1 . . . , K2 (K2≧0) and having L(k2) discrete values, and for the selected sequence of times, forming an L(k2)×L(k2) matrix whose entries are the number of transitions between any two of the L(k2) discrete values of this parameter, dividing each of the original diagonal entries by a sum of the original diagonal entries of the L(k2)×L(k2) matrix to form a modified L(k2)×L(k2) matrix, and forming an L×1 vector E2 of entries from the modified L(k2)×L(k2) matrices, where L is the sum of the values L(k2) 2 ; (v) forming an M×1 data vector E with entries including m1(v), m2(v), min(v) and max(v) for each of the vectors v=A, v=B, v=C and v=D, and including the entries of the modified L×1 vector, where M=M1+L; (vi) computing a covariance matrix F=cov(E); (vii) computing eigenvalues, λ=λ1, λ2, . . . , λM, for an equation F·V(λ)=λV(λ), where λ1≧λ2≧ . . . ≧λM; and (viii) computing a transformed matrix G=DM·F, where DM is a selected data matrix.