What separates us from lower animals and higher machines is that neither are capable of human error. Only humans are, and the great story of this race is that never in a million years will it be able to protect itself against itself.

A small case in point over the span of eternity but a large one from most other perspectives occured in September of 1976, when 176 people died over Zagreb, Yugoslavia, in the worst mid-air collision in aviation history. The story is retold tonight from the viewpoint of the air-traffic controllers who were blamed for the crash, and for whom the extinguishing of 176 souls appeared as nothing more concrete than the disappearance of two blips from a radar screen.

"Collision Course", at 8:30 on channel 5, is the first of eight programs, all getting their first television exposure in this country (though a few were actually produced here) as part of "Summershow", a bequest of sorts from Mobil Oil. Future syndicated programs on succeeding Monday nights will range from "A Party With Betty Comden and Adolph Green" to Philby, Burgess and Maclean," a real-life spy, saga.

Tonight's program, produced last year by England's Granada Television, is certainly a grim way to begin the series, but also a fairly compelling one. If docu-dramas must be done -- reconstructing actual events and playing them out with scripts and actors -- perhaps they should all have this film's cold, methodical and yet not unaffecting style; "Collision Course" is so dry it almost cracks, but it builds to two climaxes with precision and authority.

The first half of the 90-minute film leads to the crash itself, seen mostly from the control tower vantage point where the Yugoslav flight controllers controllers do their jobs and exchange small talk. Dialogue spoken between flight controllers and aircraft is taken from actual transcripts, the prologue has informed us; the small talk, one assumes ("Have you seen the price of denim lately?") was fabricated.

Without any real melodramatic filigree, director Leslie Woodhead and writer Martin Thompson tighten the screws deftly, focusing on the role of an air-traffic controller named Tasic, who is movingly and hauntingly played by Anthony Sher and who, in the second half of the program, is tried, under Yugoslav law, on criminal charges of negligence that could have earned him 20 years in prison.

The film is not an expose of laxness on the part of airline personnel; it turns out that a "system" was to be blame. Still, we do see the pilots of the British Trident involved in the crash doing a crossword puzzle in the cockpit moments before it occurred, while in the DC-9 cockpit, there's a discussion of "cheap tomahtoes." The last nine minutes efore the crash are painstakingly and grippingly played out in real time. The look on Sher's face when he realizes that an error has brought about a terrible calamity is a striking embodiment of human helplessness.

In the trial portion of the film, a gallant British lawyer, friend to one of the crash victims, strides forward a bit too grandly to defend the air- traffic controllers. The crash is blamed on an unholy alliance between men and machines (including malfunctioning radar) -- on "a system which has grown into a monster which we have not had the time to learn how to control.

There's no conscious attempt to wreak parallels here, but systems that have grown into monsters seem more populous on this planet every day, and so though the focus of "Collision Course" is finally quite small -- reforms did come about in the Yugoslav air-traffic system, we are told -- the repercussions are as large as one cares to make them. And in a technocratic wonderland that grows more techno and cratic every day, it is easy to make them enormous.

James Earl Jones is the imposing and agreeable host of Summershow," and although Mobile has kept commercials to a gratifying minimum, the spots that do appear are those tired old "fables" first used on the "Edward and Mrs. Simpson" show. In one, an oil company is protrayed as a friendly elephant who says, "I'm large, not fat," and we learn that oil companies deserve "a profit proportionate to their size." Could it also be that oil companies are part of a system that has grown into a monster that we have not had the time to learn how to control? I'm only asking.