Did you mean "Clacks"? Or was it an attempt to point to <a href="https://fr.wikipedia.org/wiki/Sudac_air_service" rel="nofollow">https://fr.wikipedia.org/wiki/Sudac_air_service</a> which has no English version AFAIK?<p><a href="https://parisianfields.com/2018/03/25/a-question-of-time/" rel="nofollow">https://parisianfields.com/2018/03/25/a-question-of-time/</a>
Video reference: <a href="https://www.youtube.com/watch?v=gol_p2aWrJg" rel="nofollow">https://www.youtube.com/watch?v=gol_p2aWrJg</a>