View Full Version : Understanding CAT 168 Aeronautical Ground Lighting

Negative Backtrack
7th Nov 2008, 23:33
CAP168 http://www.caa.co.uk/docs/33/CAP168.PDF (http://www.caa.co.uk/docs/33/CAP168.PDF)

Chapter 6 Aeronautical Ground Lighting

Understanding CAT 168 Aeronautical Ground Lighting - Minimum Licensing Requirements

Excuse the pun; can anyone shed some light on the minimum percentage of serviceable runway light fittings for approach high intensity inner 450m and supplementary lighting?

Section 12
Maintenance of AGL Systems

In table 6.7, does the reference to App inner 450 relate to a joint percentage of inner 450 and supplementary lighting? I ask because I can’t see a reference to supplementary lighting on its own.

I have linked to an excel table (http://airsideoperations.com/AO/agl/compliance_table.xls) to assist with my explanation so that I can hopefully better understand the text book description.view here (http://airsideoperations.com/AO/agl/compliance_table.xls)

The instance I use lets user’s input un-serviceable light fittings in the yellow column, depending on where and how I interpret the combined or independent percentage results in different outcomes.

I receive different results for CATII/III compliance depending on how I distinguish the data. I have 7 outages as an example.

Views and explanations welcome…

Negative Backtrack
21st Nov 2008, 10:27
There are three types of people in the world!

Those that can count
And those who cant count
Would this question be better placed in another forum topic. :confused:

Chris Scott
21st Nov 2008, 14:13
Hi Negative Backtrack:

Think you're in the right part of PPRuNe, but maybe we don't have many aerodrome-lighting experts: I am not one. There is an airfield-expert forumite called OverRun, who may pick up your thread eventually.

CAP 168 is an impressively large document; not the sort of tome that pilots tend to take and read on layovers. There are various technical study groups, however, in BALPA, and there may be one dealing with AGA. The Air Study Group is interested in lighting, but mainly from a pilot's perspective.

Finally found Table 6.7 on Page 38. My guess is that, as you are making a study of it, you've a better chance of interpreting what the 85% relates to than I have. I doubt you would have missed anything I'm likely to find.

My advice is to ring the CAA Safety Regulation Group, if you haven't already. You may be pleasantly surprised how nice they are, and might even find yourself talking eventually to one of the authors of the CAP. Good luck.


24th Nov 2008, 09:56

I can answer your question. The SALS are counted as being part of the INNER 450m therefore in CAT2/3 criteria the max percentage of lights u/s is 5 %. 95% being the minimum percentage of lights serviceable within the final 450m (SALS and HIA 5 CL) . Less than this and the runway cannot be used for landing in CAT2/3 conditions.

I agree CAP 168 is a monster. Even getting into the depths of correct circuitry for AGL systems. One of those books that when you put it down , you don't want to pick it up again.