Chuck Yeager was a famous test pilot. The expression means that the author will be serving as a substitute for a skilled test pilot---a poor substitute, perhaps, but the best the town can muster. It's a somewhat ironic expression.
Mrs. Smith's famous chicken casserole, made with canned mushroom soup, sour cream, and
five chicken breasts, instead of the four less generous ladies used, was Farmdale Methodist's answer to Escoffier.
Another useful expression is "poor man's ____________," which means roughly the same thing.