Calibre 280

Notes

At the end of the 1950s, Longines was again thinking of reorienting its calibres and making thinner automatic winding calibres a priority. The 22A and 19A automatic calibres had been reasonably successful but were significantly thicker than competitors automatic calibres and there was a felt need from both the technical and marketing department to make thinner automatics.The 290/280 family was the first of this new set of calibres and it did away with subsidiary seconds offerings making the base version of the movement central seconds. Additionally it changed the design of the main plate such that adding a date function would no longer increase the thickness of the calibre as it had in the 19 ASD. The 290 and 280 families are essentially the same, the 280 family being the manual wind version of the 290. All were designed and planned at about the same time and released to the market the same year. A hacking version of the 280 called the RR280 was made for the Canadian Pacific Railway.
280: center seconds
281: date
284: excenter regulator
285: excenter regulator, date