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Michael Moe

Mapt- in the FMC?

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Could this situation call for a periode of catIII approach?

 

Dunno. Look at the chart. Is it below CAT I and II mins?

 

 

 


If so - is it normal to have a selfprogrammed LEG in the fmc with the Mapt or is it of no influenze afterall during cat3?

 

Not sure what you're trying to say here, but in the United States, it's frowned upon to make user entries to STAR and Approach procedures. On an ILS approach, unless it's a special procedure, your decision altitude/height is based on altitude/height, and not a specific location, directly.

 

Some procedures (usually not ILS) have a missed approach point, though.

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Some procedures (usually not ILS) have a missed approach point, though.

 

Pretty much only VOR approaches anymore, and now we fly those with GPS overlays LOL

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Yesterday in EKCH from 20.00Z and at least to 20.20z i saw RVR decreasing below 50m on 22L and vis around 2-300 meters. Vertical clouds at 300 feet whatever that meens. Could this situation call for a periode of catIII approach?

 

With an RVR of 50m, that is actually beyond CATIII territory -- you're in for a wait/diversion if there isn't another runway with better conditions! (definitions: CATI = an approach with a decision height of >=200ft and RVR >=550m; CATII = an approach with a decision height of <200ft >=100ft and RVR >=300m; CATIIIA = decision height <100ft and RVR >=200m; CATIIIB = DH<100ft and RVR <200m >=75m).

 

75m RVR is the absolute minimum; mainly because in visibility lower than that the emergency services would have trouble finding you if you had a problem after landing, not to mention the practicalities of finding your way to the gate.

 

 

 


is it normal to have a selfprogrammed LEG in the fmc with the Mapt or is it of no influenze afterall during cat3?

 

As Kyle says, it's not good form to 'build your own' approaches in the FMC; you should just load the procedure from the database. With an ILS (particularly in low visibility) you'll almost always be working to a decision height as referenced on the charts rather than a fixed missed approach point. I imagine in the cases where there is a fixed MAPt it would be coded in the procedure you load from the database.

 

You'll notice that charts don't generally state CATIIIB minima; this is because CATIII minima are airline-specific. The operator needs approval from the regulator in order to carry out CATIII approaches; each aircraft has to be certified; and the crew have to be trained and current in low-visibility ops. Most (but by no means all) of the time, those qualified to carry out CATIII approaches will be qualified down to 0ft (i.e. no DH) -- in some states (i.e. France), however, 'no DH' ops are not permitted; in those cases there would be a 'nominal' DH (perhaps around 25ft or so).

 

That's a very brief overview; low-visibility operations (and the regulations around them) are rather complex, to say the least!

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With an RVR of 50m, that is actually beyond CATIII territory -- you're in for a wait/diversion if there isn't another runway with better conditions! (definitions: CATI = an approach with a decision height of >=200ft and RVR >=550m; CATII = an approach with a decision height of <200ft >=100ft and RVR >=300m; CATIIIA = decision height <100ft and RVR >=200m; CATIIIB = DH<100ft and RVR <200m >=75m).

 

75m RVR is the absolute minimum; mainly because in visibility lower than that the emergency services would have trouble finding you if you had a problem after landing, not to mention the practicalities of finding your way to the gate.

 

 

As Kyle says, it's not good form to 'build your own' approaches in the FMC; you should just load the procedure from the database. With an ILS (particularly in low visibility) you'll almost always be working to a decision height as referenced on the charts rather than a fixed missed approach point. I imagine in the cases where there is a fixed MAPt it would be coded in the procedure you load from the database.

 

You'll notice that charts don't generally state CATIIIB minima; this is because CATIII minima are airline-specific. The operator needs approval from the regulator in order to carry out CATIII approaches; each aircraft has to be certified; and the crew have to be trained and current in low-visibility ops. Most (but by no means all) of the time, those qualified to carry out CATIII approaches will be qualified down to 0ft (i.e. no DH) -- in some states (i.e. France), however, 'no DH' ops are not permitted; in those cases there would be a 'nominal' DH (perhaps around 25ft or so).

 

That's a very brief overview; low-visibility operations (and the regulations around them) are rather complex, to say the least!

 

Thank you both. It was between 20.20z and 2040z in EKCH 22L 25.1.15.Very unusual metar in copenhagen.

 

Michael Moe

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