Thanks, I wasn't aware that there is still a human observer method in the UK. I have not seen the IRVR term used anywhere else. In fact, the Jepp approach charts for LHR just use RVR(including for CAT II/III approaches) but the term IRVR is used in the reference pages. Not sure why.
Does the RVR minimum value for approaches at the bottom of the page just mean the lower of the RVR or IRVR value available?
Human observation? Is that someone in a shack near the end of the runway?
Last edited by JammedStab; 25th Nov 2016 at 16:23.