Thanks for the reply (and so fast!).
That they serve as approach lights.... totally forgotten about that!
We are required to count the lights before we go in take-off.
But how do I know when the lights are 30m apart?
On the LIDO charts there is only a statement of CL 15m. And the lowvis charts doesn't come with any nr of spacing of the CL.
Strange thing (in my opinion) is that we need an RVR of 125m and only a visual segment of 90m, 6 lights (+ 12 m obscured on the 737) is a total of 102m visual segment. Where is the other 23m?