"I've seen all 33 Clint Eastwood movies," a dismayed friend confessed after the screening of "Firefox," "and I've never felt more disappointed." Both loyal fans and neutral observers may agree that Eastwood has steered himself into a peculiarly murky flight path on this occasion. Literally murky, too. Much of the picture is so miserably underlit, even before the action reaches the Soviet Union, where gloom is meant to prevail.

The basic plot device is a Mission Impossible of self-evident wackiness, augmented by ominous gleanings from the John Le Carre' inventory and futuristic aerial spectacles that borrow heavily from "Star Wars," perhaps because the special effects supervisor, John Dykstra, made his reputation on that credit.

Eastwood plays an American jet pilot named Mitchell Gant, who is introduced as a quivering traumatic question mark, so haunted by the memory of combat, capture and a napalmed little girl in Vietnam that he cowers in the corner of his cabin in the Alaskan woods when an Army helicopter drops in for a call.

Despite his apparent psychological dysfunction, officially diagnosed as delayed stress syndrome, Gant has been chosen by desperate superiors as the flier most likely to save the West from imminent surrender to Soviet intimidation. His mission, should he accept it, a foregone conclusion: Infiltrate a top-secret air base somewhere in Russia and hijack one of the two prototypes for an awesomely advanced fighter-bomber, the Mig31, nicknamed Firefox, which threatens to tip the balance of power decisively, irrevocably, once and for all to Soviet militarism.

Assuming that his delayed stress syndrome won't flare up at an inconvenient moment--naturally, it flares up repeatedly to provide brief, ludicrous injections of suspense--Gant is supposed to be "the best we've got" for this do-or-die mission on the strength of flying experience and skill, Russian parentage and command of a unit called the Aggressor Squadron, which routinely assumes the role of hostile pilots in jet combat exercises. Nevertheless, these "qualifications" fail to satisfy certain common-sense objections to the premise right from the start, and they fail even more emphatically once the hero is slipped into Russia and escorted to his target by intrepid, selfless dissidents, curiously indistinguishable from the idealized Resistance fighters in action melodramas devoted to World War II.

For a personality of obvious professional astuteness and patriotic sincerity, Eastwood betrays a peculiarly far-fetched sense of anxiety about Soviet inventiveness. There's something not only exaggerated but also insulting about the very concept of American and British military strategists finding themselves so trumped by the hi-tech Russians that they must resort to an utterly impossible hijacking to avert disaster.

Eastwood's slant on the strategic situation is decidedly topsy-turvy, and this dizziness could have unintended consequences. For example, the craven pointlessness of Gant's mission tends to enhance sympathy for the Soviet security personnel entrusted with protecting the new planes. Whether Eastwood appreciates it or not, a sentiment operates here that was once described to me as follows by a friend who'd worked for a national security agency: "The guys hired to protect your secrets tend to be nobler sorts than the guys hired to steal their secrets."

If the Firefox is really an Ultimate Weapon, it's clear to see that sabotage would be an easier and more reliable countermeasure than Gant's shenanigans. Wouldn't the same dissidents who willingly sacrifice their lives assisting Gant do the same to obstruct the development or deployment of the Firefox? Why ask them to smuggle around this klutzy, flaky American pilot? As a matter of fact, the movie early on costs itself the willing suspension of disbelief. When a grim-lipped intelligence officer described two dazzling features of the Firefox--it can fly at Mach 6 and has a weapons system triggered by the pilot's thought waves--it seemed to me that the game was up. Why would such wrinkles recommend themselves to Soviet authorities? It seems more likely that they'd be paralyzed at the latitude these improvements would give their pilots. The Firefox sounds like an irresistible temptation to defect at six times the speed of sound and thought-control a missile or two at Party headquarters as a farewell gesture.

Actually, the Firefox doesn't look all that formidable on the screen. On the ground it appears too ponderous to get off the ground. The Flying Blockhouse would be a better nickname. Dykstra and the model designers seem to have fabricated it by combining Darth Vader's helmet with the space fighters in "Star Wars." The only in-flight special effect that stirs the imagination is the parallel curtains of water that suddenly erupt in the wake of the plane as it whooshes across the surface of the ocean.

If memory serves, the Ultimate Mig has been a threat that has never quite become operational for the last three decades. When I was a schoolboy, I recall being vaguely alarmed by stories from Korea intimating that our pilots were at a dreadful disadvantage compared with the Chinese pilots in their lickety-split new Migs. I suppose it's never wise to get overconfident about such matters, but isn't the Mig menace frequently being shot down in real life, most recently by the Israeli Air Force?

Ironically, the Israelis may have shot down "Firefox" at the same time. This isn't the ideal launching time for a movie that depends on a nightmare of Mig supremacy. The irony is weirdly enhanced by the fact that Eastwood makes a special, ultimately mawkish effort in "Firefox" to glorify Soviet dissidents, whom his character identifies exclusively with Jews. "What is it with you Jews, anyway?" he asks at one excruciating point. "Don't you ever get tired of fighting City Hall?" As dumb luck would have it, the dissident he's quizzing doesn't happen to be Jewish after all (his wife was, and he's trying to carry on in her memory), so these eloquent questions go begging for suitable answers.

Yeeeesshh, Clyde, I guess this big galoot means well, but could you please haul him away and get his mind back on something more frivolous?