CatIII ILS Landing at EGLL (Heathrow) Fails in this aircraft?

[Tabs 2,790]

I still don't understand why people are looking for a fix when there was NO problem !By editing the data in ADE and saving it just adds some text.It has nothing to do with making an autoland.An autoland is possible at the 4 Heathrow airports.If you can't autoland then you are doing something wrong !!

You're exactly right - we do not read any flags that say CATIII or anything like that in the AFCAD. Even in real life the plane will attempt to autoland on any ILS runway - there's no such thing as the plane "knowing" that it's landing on a CATIII certified runway. That only has to do with the tolerances and testing regimen of the ILS beams, the exact configuration of the runway threshold and TDZ, and the pilots' and the aircraft's certifications.

[ST1322 10]

Gentleman, he never responded go my q, which was about baro setting. If this thing is not set up, cat3 will not arm.

[Robert McDonald 167]

Yes, I always reset the barometric pressure as I descend from cruise altitude, several times. I double checked the runway threshold setting (77 feet) and length (varies between 27L and 27R) to be correct. I appreciate you mentioning it though, next time I have a CAT III refuse to arm, I will reset the baro and see if it helps :D!Of course Ryan is the 'last word' so something I did must have created the troubles... and I'm sure you are all quite right that editing the properties of the runway using ADE isn't the 'fix' for my issue.On the other hand, for some unknown reason, I can now land CATIII on either runway at EGLL, so I'm happy for that much. The why is less important now that the issue is resolved, other than I have no wish to spread wrong information.Also, I acknowledge the myriad number of hang-on software (scenery, weather, flight planning, VATSIM, etc.) combined with an amazing number of differing controllers and other PC hardware provides a number of ways that unexpected results can occur during flight.Thank goodness we have this fine forum to share experience and provide guidance for those of us newbie pilots who are still at the steep end of the learning curve.Ryan- When will PDMG release the new Boeing 787 Dreamliner? Now THAT is one bad airplane! ;) I am a huge PDMG fan btw--Since I discovered the NGX I haven't flown any other 737.

[kevinh 409]

How do you do that? The CRS window doesn't matter as far as I know.It's the frequency and what FSX says the heading is versus what the NGX thinks it is. You can put whatever you want in the course window and the a/p will follow the LOC anyway.

The CRS selection does matter. The AP will attempt to follow the localiser and fly the selected course. This creates a lateral error, so the aircraft will touch down offset from the centreline.Kevin Hall

[Thunderbird8 1]

Are you 100% sure about that? Have you actually tried it?

[janpitor 2]

Yes, I always reset the barometric pressure as I descend from cruise altitude, several times. I double checked the runway threshold setting (77 feet) and length (varies between 27L and 27R) to be correct. I appreciate you mentioning it though, next time I have a CAT III refuse to arm, I will reset the baro and see if it helps :D! Of course Ryan is the 'last word' so something I did must have created the troubles... and I'm sure you are all quite right that editing the properties of the runway using ADE isn't the 'fix' for my issue. On the other hand, for some unknown reason, I can now land CATIII on either runway at EGLL, so I'm happy for that much. The why is less important now that the issue is resolved, other than I have no wish to spread wrong information. Also, I acknowledge the myriad number of hang-on software (scenery, weather, flight planning, VATSIM, etc.) combined with an amazing number of differing controllers and other PC hardware provides a number of ways that unexpected results can occur during flight. Thank goodness we have this fine forum to share experience and provide guidance for those of us newbie pilots who are still at the steep end of the learning curve. Ryan- When will PDMG release the new Boeing 787 Dreamliner? Now THAT is one bad airplane! ;) I am a huge PDMG fan btw--Since I discovered the NGX I haven't flown any other 737.

I think he meant setting of minimums from baro to radio

[kevinh 409]

Are you 100% sure about that? Have you actually tried it?

Yes. I've not tried it in the NGX yet, but I have in a full flight sim and if the inbound course is set wrong it creates a lateral offset. Although the localiser is a fixed track, the autopilot needs to know what that track is. If you get that input wrong it can't follow the localiser properly.Kevin Hall

[Thunderbird8 1]

Reason I ask is that a few times I've forgotten to set both course buttons and it hasn't made a blind bit of difference. The LOC and AP engaged as normal and on the correct track. Hmmmm.

[N517AH 0]

Reason I ask is that a few times I've forgotten to set both course buttons and it hasn't made a blind bit of difference. The LOC and AP engaged as normal and on the correct track. Hmmmm.

Do you have the "set fsx loc crs" option enabled?

[Thunderbird8 1]

Aha Sean, yes it seems I do. So, do I disable that, then go to the FSX map and then input whatever the map says is the right ILS course?

[JRBarrett 3,124]

The CRS selection does matter. The AP will attempt to follow the localiser and fly the selected course. This creates a lateral error, so the aircraft will touch down offset from the centreline.Kevin Hall

It appears to act that way in FSX - where an ILS localizer is treated like a VOR radial. Definitely not the way a real ILS works, where the localizer center is solely a result of the modulation characteristics of the signal radiated by the directional localizer antenna located at the far end of a given ILS runway.

[Thunderbird8 1]

Right, cool. Thanks

[Spin737 102]

The AFDS does look at the CRS, but I believe it's only for the intercept calculation. I was flying in to Kodiak a few years ago and the captain didn't bother to set the FAC in the MCP on his side. So, as we arc around from the north to intercept, on LOC capture, the plane starts turning away from the course. So, it's not quite so simple.

[kevinh 409]

It appears to act that way in FSX - where an ILS localizer is treated like a VOR radial. Definitely not the way a real ILS works, where the localizer center is solely a result of the modulation characteristics of the signal radiated by the directional localizer antenna located at the far end of a given ILS runway.

Sorry, but it is that way in real life. I know a VOR and LOC are different in how they transmit. The autopilot cannot track the LOC signal properly unless it knows the inbound course. If you don't get the course input right the aircraft won't track down the centre of the localiser. I've seen this and done it myself in a full flight simulator.Kevin Hall

[kevinh 409]

The AFDS does look at the CRS, but I believe it's only for the intercept calculation. I was flying in to Kodiak a few years ago and the captain didn't bother to set the FAC in the MCP on his side. So, as we arc around from the north to intercept, on LOC capture, the plane starts turning away from the course. So, it's not quite so simple.

Yes, setting the inbound course certainly helps the intercept, but it's also necessary to track the localiser down to touch down too. If you get a chance on a coupled approach try changing the selected course a degree or two when on the localiser and see what happens to the deviation bar.Kevin Hall