IRVR and Absolute Minima (UK Only)

[niknak]

We have a Cat One ILS on one end and NDB approach on the recipricol runway therefore we have to apply Abslute Minima when the RVR dictates.

Our IRVR gives us a Touchdown and a Stop End (we dont have a mid point), MATS Pt 1 states that:

If only two values are to be passed, they are to be individually identified, e.g.
“RVR runway (designator) Touchdown 650 — Stop End 550 metres”.

But which is to be used to determine Absolute Minima?

I know that logic dictates that you should use the Touch Down reading and the pilot would use the Stop End for information purpose only, but does anyone know where this is written down in CAA Doc's?

Thanks.

[Spitoon]

I'm pretty sure that it's the TDZ - mainly because that's the only one that's required for Cat I and non-precision ops.

There was an ATSIN (no 19, I think) which I recall explained it all very clearly - but this is now withdrawn and I've never seen it incorporated in any other doc.

[Sir George Cayley]

Have you sought clarification from your CAA ATS Ops Inspector? He or she would love to ponder such a question before referring it to the big grey building sat abeam LGW 26L

You could always send a Firefighter out to count lights in the old fashioned way or persuade the bean counters to buy a 3rd IRVR - or shut when it gets a bit murky.

'Course if the a/c on approach has EVS and HUDLS then let them get on with it.

The above is guidance not to be inserted in MATS Pt 2

Sir George Cayley

[niknak]

We await a reply from SRG.............

[LXGB]

Don't hold your breath!

[BOAC]

If it is any help, EU OPS Table 6a in Appendix 1 (New) to OPS 1.430 (EUOPS) states that failure of mid, stop AND TD have no effect on Cat I ops, so either TD RVR or CONVERTED met vis would be acceptable. Stop end is not required.