By Paul Watkins

Houghton Mifflin. 310 pp. $18.95

Paul Watkins seems well on his way to becoming an exceptionally prolific novelist. His first book, "Night Over Day Over Night," was published to critical acclaim when he was 23. "In the Blue Light of African Dreams" is his third; he is now 26. Each book has had a different setting and perspective. "Night" was told by a World War II soldier -- who happened to be in the German SS. Charlie Halifax, the hero of "Blue Light," is an American World War I fighter pilot who attempts, in 1927, a nonstop flight from Paris to New York. His history, and the reason for his effort, form the substance of this book. It's the work of a vivid imagination.

Halifax has fled his hometown in Pennsylvania to escape his brother's fate, death in the coal mines. He joins the Lafayette Escadrille -- the famed corps of Americans who served in the Great War while America was still officially neutral. After winning the Croix de Guerre, he's badly burned and half disfigured by fire aloft. In the hospital, he concludes his luck is up -- the war is nearly over, after all -- and he attempts to catch a boat home; to desert, in a word.

He's caught halfway up the gangplank and given a choice: the firing squad or 20 years in the Foreign Legion. The Legion is where we find him at the beginning of the book, in North Africa. Under the thumb of the despicable Capt. Serailler, Halifax is smuggling arms by airplane to the very Arabs against whom the French are engaged in desperate warfare.

The tone of the narrative is emotionally flat: Halifax's spirit has been deadened by war, its inequities and the injuries he has suffered. Nevertheless, the language bursts with color, and the story is never short of plot and characterization. It's an easy read. The short, declarative sentences are evocative of Hemingway, but without the fanciful macho. Watkins is a writer of formidable gifts.

However, if someone sets out to write a realistic novel in which the act of flying an airplane is frequently at center stage, he should probably know just a little bit about the subject -- or enlist the aid of someone who does. Had he done so, Watkins might not have embarrassed himself and his otherwise excellent prose with sentences such as "If his engine gave out, either he'd be close enough to the ground to land the plane before it dropped into a tailspin or he wouldn't" or "Halifax cut the throttle, keeping the stick straight in case they nosed into a dive." The book is laced with such dissonances and for any pilot, they will constitute fatal flaws.

So what about non-pilot readers? To what extent does a writer have the duty to be true to his subject?a

If a reader can't trust the writer to tell the truth about the physical world -- if he's too careless, just doesn't care -- how can he be trusted to tell any other kind of truth, psychological or philosophical? In a work of serious literary intent -- and you can tell this is such, because the hero doesn't have any fun -- it seems that the writer should be held to a higher standard of accuracy than in the action fantasies that populate bestseller lists.

Years ago, a physics student found the following sentence, somewhere in Lawrence Durrell's "Alexandria Quartet": "The city had two centers of gravity: the true and magnetic north of her personality." The student threw the book down in disgust. If a writer displayed such disrespect for the meaning of language, the student thought, it was a waste of time trying to unravel his intent. For readers who disagree, "In the Blue Light of African Dreams" offers language that is original and often highly pleasurable -- if not necessarily true.

The reviewer, a longtime pilot, is finishing a book about her experiences as a driver in the Indianapolis 500.