ECET

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The ECET (End of civil evening twilight), the "end of civil evening twilight " , is a term used in aviation that defines the point in time at which the center of the sun disk is 6 degrees below the mean horizon .

Civil twilight ends - depending on the time of year - in Central Europe around 30 minutes after sunset . Their duration depends on the season and latitude . The lighting conditions at the ECET allow prominent landmarks to be seen from the air, but at the same time bright stars are already visible in the sky. In aviation , especially in Austria and Switzerland , it is important insofar as, at the time of ECET, the daytime visual flight conditions are no longer given and flights only according to the specifications for night vision flight (NVFR) or instrument flight rules (IFR) must be carried out.

Example Zurich:

  • June 15, 2012: ECET 10:05 p.m. (summer time)
  • December 15, 2012: ECET 5:11 p.m. (winter time)

The opposite of the ECET is the BCMT ( Begin of civil morning twilight, "beginning of civil dawn" ). It takes place accordingly before sunrise .

Example Zurich:

  • June 15, 2012: BCMT 4:48 a.m. (daylight saving time)
  • December 15, 2012: BCMT 7:31 am (winter time)

Web links

Individual evidence

  1. ↑ AIP Austria, Part GEN 2.7-1 .