Approach lighting failure at night
 

Mornin'

Reference EU-Ops with the following scenario:

It's night, weather/cloud not sparkling but should be OK. Cat1 ILS and the approach lighting has failed leaving fully serviceable runway edge, threshold wing bars, stop end, PAPIs etc.

What are the legalities of making an approach to this r/w? What if they failed before dispatch or at a time after commencement of the approach? I assume that maybe higher minima might apply and that there might be further constraints if the flight was public transport. Basically, can it be done?

Thanks for the help,
L

You will need to adjust your approach RVR requirements for "NIL FACILITIES" You can still make an approach so long as the RVR is at or above the adjusted value.

All airport lighting is interleaved. That is to comply with ICAO Annex 14 which requires that no 2 adjacent lights should both fail.

What it means is that separate circuits power 50% of each service e.g. Approach lights, Edge Threshold and End.

So the chances of both circuits failing and robbing you of all the approach lights is in to the 10 x e7 category.

EU Ops gives a table of degradation to help permit commanders decide to land or divert but it takes no account of real world command control and power supply provisions.

Sir George Cayley

The table applies at all times unless you have the req vis ref for landing on a cat I app.

Unless the backhoe operator dug up just the right(wrong!) patch of dirt.

Failure rates that assume total isolation of redundant systems are allways a bit suspect in my book.

Yes it can be done. Higher RVR minima apply but no change to the DA/H. An example I just looked at (EGPD Rwy 16) gives Cat1 RVR 550m with 'full' lighting, 750m with 'limited' and 1200m with 'ALS out'. The only difference at night is, if RVR equipment fails, then you can factor reported met vis by (I think) 1.5 to get RVR equivalent.

The whole issue about AWO is probability. Basically it means that an aircraft may not be on the RWY or close to the ground unless certain conditions are fulfilled.