A nifty couple of ideas for domestic-aviation extortion are buried deep under acres of sawdust in this swollen thriller from Gruenfeld (Irreparable Harm, 1993). When an Alpha Airlines 727, guided by the latest in computerized guidance systems, overshoots its landing field and nearly crashes into the campus of Western Washington University, the troubleshooters--headed by National Transportation Safety Board investigator Amy Goldberg and FBI agent Jack Webster (ex-Navy, ex- NTSB)--soon realize (nifty idea #1) the problem is with the guidance system itself: Somebody's been able to send the plane signals misdirecting its landing with unnerving predictability. How unnerving? Well, a demand for a $5 million payoff describing the plane's erratic behavior was sent to the NTSB hours before the near-fatal mishap. As Goldberg and Webster hustle to satisfy the terms dictated by the blackmailer they've come to call Captain Marvel, and as they watch the $5 million they've deposited in the FundsNet interbank system get siphoned off in (nifty idea #2) a series of ATM withdrawals, they scramble to figure out who Marvel is, why the blackmail figure is so low, how anybody could tamper with the AutoNav systems, and what action they can take to prevent another catastrophe. But after the mass AutoNav reprogramming they've relied on falls disastrously short, after they cut off the ATM withdrawals at $2 million (at the insistence of a know-nothing senator), and after Marvel choreographs a fatal Alpha crash outside Indianapolis, they realize they'll have to rely on outsized individual heroes like ATM designer Florence Hartzig, maverick microchip designer Phyllis Dalek (but where is she, and why won't she call her office?), and, ultimately, veteran fighter pilot Bo Kincaid. Throughout, beefy chunks of flashback substitute for character development and head off the threat of sustained suspense. The result is a lumpy, lumbering union of John Waynes of both sexes.