The bright display system presented raw radar returns overlaid by a video map showing airspace, routes and other important features. There was no labelling of returns, however SSR returns were displayed with a geometric symbol (e.g. rectangle, triangle) depending on the code being squawked. Target identification was done mostly by distance reports or observing a directed turn. Ident was maintained using 'shrimp boats' - pieces of perspex with the target's callsign written on them in chinagraph pencil, moistened and stuck on the screen by surface tension. The shrimp boats had to be manually moved along as the target moved. Two shrimp boats can be seen on the display in this photograph, as can a number of the 'slash' marks indicating a primary radar return.
Dick, did you look at any of the links provided? Did you read any of the posts?
Do you remember how primitive the ATC radar really was circa 1980? Are you really suggesting that
wherever radar coverage existed the aircraft should have been under positive control, as that would have been the only option in those days? It was CTA or not, no "sort of". That's why we had CTA steps. Can you imagine how this system would have coped with multitudes of light aircraft going where ever they pleased? How many "shrimp boats" would be stuck on that screen, being physically kept track of and moved around by the operator? It was designed as a tool to manage aircraft on fixed routes in fixed airspace doing predictable things. You were cranky enough back then when ATC wouldn't let you go where you wanted in your chopper. Imagine if every where you wanted to go was controlled?
why couldn't BASI recommend such a change in the accident report!
Because it was 1981, not the 90's, BASI obviously didn't think it was a contributing factor, and probably realised it was impossible to implement a change like that at that time anyway, especially as a result of one accident that had a multitude of other causes. By the time you started changing things in the 90's, technology had moved on a lot.