Breaking the Sound Barrier is a very misleading title. Those who expect a documentary on the development of supersonic aircraft will be only partially satisfied (1 for one don't even know whether the documentary is true).Others who will undoubtedly stay away from the film because they anticipate a dull, dry scientific account will miss an intense and subtle human drama.

Breaking the Sound Barrier does deal with a British aircraft company's attempts to design a plane faster than the speed of sound. More than this, though, it is concerned with the company owner's persistence in launching new attempts, even at the cost of human life.

Sir Ralph Richardson is cast as John Ridgeway, a manufacturer who was once a dare-devil aviator and who feels the same way about breaking the sound barrier as some men would about exploring virgin territory. Ridgeway must send more planes and aviators to attempt the seemingly impossible, even after his son-in-law crashes in the first test plane. Although he alienates his daughter and wonders himself whether or not his vision is an evil spirit, he continues. When one of his planes finally beats the barrier, Ridgeway feels no clation--only, perhaps, relief.

Richardson, who won the New York critics' award, treats his role with a remarkable restraint. Ridgeway is not a scientist himself; he is a single-minded industrialist who carries scientists, designers, and pilots along in the wake of his enthusiasm. He has no sympathy with failure or timidity, and although he suffers at his son-in-law's death, one feels that he considers it a cheap price for the ultimate gain. This is a difficult part to play. Some actors might make Ridgeway a bare, two-dimensional character, since Terrence Rattigan's script alone does not delineate him sufficiently. But Richardson, by his voice inflection, doodling at his desk, and various other mannerisms fills out the role.

Ann Todd, as Ridgeway's daughter, is the sympathetic character, the woman who watches her husband and brother die for something she considers very unimportant. She seems to be purposely underplaying, but since the part has such highly emotional possibilities, I think this is probably better than the other extreme.

The picture has some flaws. It sometimes seems that the camera is swinging like a pendulum from homelife to airport life and back again. The airshots are not varied, and the pilot and his instruents are usually shown from the same angle. But these are minor defects. And with the tension generated by the action, you may not even notice them.