  In recent work, Baird et al. have introduced a generalized Maslov index which
allows oscillation techniques that have previously been restricted to
eigenvalue problems with underlying Hamiltonian structure to be extended to the
non-Hamiltonian setting [T. J. Baird, P. Cornwell, G. Cox, C. Jones, and R.
Marangell, Generalized Maslov indices for non-Hamiltonian systems, SIAM J.
Math. Anal. 54 (2022) 1623-1668]. We show that this approach can be implemented
in the analysis of spectral instability for nonlinear waves, taking as our
setting a class of equations previously investigated by Pego and Weinstein via
the Evans function [R. L. Pego and M. I. Weinstein, Eigenvalues, and
instabilities of solitary waves, Phil. Trans. R. Soc. Lond. A 340 (1992)
47-94].
