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GraemeBr

Cat II/III approaches

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I have a question regarding if autoland is available for all ILS approaches (RW and in the sim). While landing in low vis at PAEI last night I configured for an autoland which I don't use very often. I didn't get a LAND3 announced at the appropriate point and ended up disconnecting at minimums and landing manually. Now I don't know if I just missed something in the procedure, but it got me thinking about Cat II/III landings and perhaps if some ILS approaches don't give LAND3 because they aren't certified for it. I did some searching online and now understand a bit more about the complex criteria of Cat II/III operations.So I understand that Cat I/II/III and sub-variants are related to the visibility minimums i.e. RVR and also the serviceability of the airfield equipment and that Cat III A,B (and C when/if it becomes certified) operations at minimums require full autoland due to the lack of visual references.But I couldn't find an answer to whether or not there are different grades of ILS certification i.e. which might not be accurate enough to allow a safe autoland (regardless of weather conditions). If that is the case how would a pilot know from the charts if he could use autoland or not.Secondly I looked at some charts from UK and US. On the UK charts including major runways like Heathrows there is only mention of Cat I/II i.e. no Cat III. On the US charts I couldn't find any mention of runway Cat's. I assume the stated minimums infer which category the approach is certified to. But why is Cat III not mentioned on the UK charts?And finally if there are differences if there are cases where certain ILS approaches do not support autoland is this included in the NGX and hence explain which I appeared to experience last night?Hopefully someone with some RW knowledge can help me here. ThanksGraeme

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I don't have any RW knowledge regarding this, but I know that you can fly an CAT III approach on every runway in FSX which is ILS equipped.BTW, a quick forum search will help you it's been discussed here many times.

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CATIII approaches are not on the charts because no altitude/height minima are applicable as far as the aeronautical authorities concern. Operators do have their own criteria.FSX and NGX will gladly accept a CAT III approach for all ILS's.About the different grades: all CAT III ILS approaches are autoland approaches. Charts do not indicate wether an ILS approach is CAT III certified. You need to read that in the aerodromes AIP. Furthermore, when you perform a CATIII approach, you need to inform ATC because in that case aircraft on the ground need to be kept away from "the critical area" to avoid that they disturb the ILS signal.So the controller would tell you that you cannot autoland on that approach.If you keep getting trouble autolanding, try to describe step by step what you do and make screenshots. People here will be glad to help you out.Bert Van Bulck

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Real world, you should advise ATC every time you plan an auto-land in non-LVP conditions. They need to keep ILS critical areas clear, otherwise your auto land might not be successful. Big metal objects like other aircraft will affect the ILS signals and therefore your auto land. ATC will increase separation and hold other aircraft at the critical hold lines if departing in order to keep your signal clear. They do this automatically if LVP procedures are in effect as advertised on the ATIS. That is why if you plan to use an auto land in non LVP conditions you need to let them know.

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About the different grades: all CAT III ILS approaches are autoland approaches. Charts do not indicate wether an ILS approach is CAT III certified. You need to read that in the aerodromes AIP.Furthermore, when you perform a CATIII approach, you need to inform ATC because in that case aircraft on the ground need to be kept away from "the critical area" to avoid that they disturb the ILS signal.
Most of the larger airports in the US have separate charts for CATI and CATII/III approaches.CATIII can have minima, depending on the type. The ILS critical area should be protected automatically when the weather is low, so you should hopefully only have to alert ATC if you're doing an autoland if the weather is better than 800' or 2sm in the US. In other parts of the world, they have holding points on the taxi route to keep you clear.

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Most of the larger airports in the US have separate charts for CATI and CATII/III approaches.CATIII can have minima, depending on the type. The ILS critical area should be protected automatically when the weather is low, so you should hopefully only have to alert ATC if you're doing an autoland if the weather is better than 800' or 2sm in the US. In other parts of the world, they have holding points on the taxi route to keep you clear.
"CATIII can have minima": you refer to RVR or actual altitude/height?True: in case weather is bad, the area will be protected automatically. But I believe the ATIS should state LVP in progress, no?Bert Van Bulck

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Check your plane's configuration to see if it has the proper equipment for autoland (I forget what the two settings are, but you should be able to search for it in the forum). The PMDG house liveries all have the required configuration but, for example, the Southwest liveries do not (probably a reflection of RW).

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"CATIII can have minima": you refer to RVR or actual altitude/height?True: in case weather is bad, the area will be protected automatically. But I believe the ATIS should state LVP in progress, no?Bert Van Bulck
For minima, I think it probably depends on the company's OPS Specs, but CATIII A&B can have DH and they both have RVR requirements. For my company, we can do CATIII HUD+Autoland down to 30RA.

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In real life you can't legally autoland unless the runway and ILS are certified for it. The plane doesn't know any better and will attempt it with any ILS signal, but you're not guaranteed accuracy unless everything is certified.

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Legal requirements play a large part in the reality of autolands and certification. There are stringent reuqirements that airports must be able to fulfil to obtain even CAT IIIa certification. When Cat IIIa was being certified at LZIB airport, I learnt, that even Cat IIIa was about two or three times more expensive to operate than Cat II. And all that while the ILS itself is basically the same (bar some items such as power redundancy). That means, that most CAT II ILS systems can support an autoland even in real life. The big difference, if something goes awry on a say CAT IIIb autoland, and you end up landing sideways on the grass beside the runway, it is someone elses fault unless you failed to identify for. ex. an excess deviation. on CAT II, if you autolanded and it went wrong, you had 200ft to react, and it is your fault.@Jack: All PMDG NGX are capable of autoland. There seems to be a misconception in this forum, that only a FAIL OP is autoland and that it is a common option. That is not true, triple channel FAIL OP autoland capable 737NGs are probably a double digit number out of thousands built. All other 737NGs (maybe save a few outballs such as SWA 737NGs back when they did not have A/T operative, if NGs ever did that) can and do autoland even with fail passive option, without rollout mode, and without LAND 3 annunciations (unless the airline dooes not maintain LVOps certification, in which case, I guess their NGs do not autoland, but can...). An indication of whether aircraft has FAIL OP autoland is a C/R button under SYS button. Look it up for example on a-net, very few have that.

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