ILS downgraded to CAT3
Join Date: May 2004
Location: UK
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Aye down to CAT3 A.
My favourite notam (yes I do have one and yes I am sad) is the one at AMS detailing the "migrating geese" that have been crossing the airfield "between 500ft-700ft". As long as they are cleared through at 600ft, thats CPL standard migration!
My favourite notam (yes I do have one and yes I am sad) is the one at AMS detailing the "migrating geese" that have been crossing the airfield "between 500ft-700ft". As long as they are cleared through at 600ft, thats CPL standard migration!
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From the ground equipment perspective, an ILS either supports CAT 3 or it doesn't. The distinction between CAT 3 A, B or C is operational and is based on aircraft and crew capability, facilitating different decision points.
I agree with Artie, downgraded from what?
I agree with Artie, downgraded from what?
Join Date: Aug 2007
Location: The Netherlands
Age: 67
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Cat III
The full capability of Cat III is Cat III E4.
Anything less is a downgraded situation.
Full capability means that, if aircraft is certified and fully serviceable and crew is certified and authorized, Cat III b without Decision Height is possible with RVR of 75 m.
A downgrade to Cat III E3 or Cat III D4 could impose limits such as minimum RVR 125, or 200 m, or Decision Height 15 ft, or 25 ft, or Cat 3 a, DH 50 ft and RVR 200 m. You would have to check your operational manuals for details.
Anything less is a downgraded situation.
Full capability means that, if aircraft is certified and fully serviceable and crew is certified and authorized, Cat III b without Decision Height is possible with RVR of 75 m.
A downgrade to Cat III E3 or Cat III D4 could impose limits such as minimum RVR 125, or 200 m, or Decision Height 15 ft, or 25 ft, or Cat 3 a, DH 50 ft and RVR 200 m. You would have to check your operational manuals for details.
Join Date: Aug 2007
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References
Sorry, at the moment I am enroute for a couple of days and I don't have the books with me.
I do know we have, in our OM (operations manual) a table spelling out the consequences of e.g. III E3 downgrading.
A couple of years ago we had a bit more extensive info about it, but in the drive to more simplification this info was skipped from our books.
Basically the suffixes indicate to what point along the centerline of the runway, what the integrity of the localizer signal is. (1 being low integrity, 4 high, T is 'till touchdown point, D and E closer to the stop end of the runway, if I recall correctly). I think that the philosofy of NOTAM writing has gone more in the direction of stating the result. Cat 1 T3 for instance could mean " no autoland allowed" / better option is to state that restriction, rather than to notify airmen of the T3 status and let them sort it out in their own books.
I do know we have, in our OM (operations manual) a table spelling out the consequences of e.g. III E3 downgrading.
A couple of years ago we had a bit more extensive info about it, but in the drive to more simplification this info was skipped from our books.
Basically the suffixes indicate to what point along the centerline of the runway, what the integrity of the localizer signal is. (1 being low integrity, 4 high, T is 'till touchdown point, D and E closer to the stop end of the runway, if I recall correctly). I think that the philosofy of NOTAM writing has gone more in the direction of stating the result. Cat 1 T3 for instance could mean " no autoland allowed" / better option is to state that restriction, rather than to notify airmen of the T3 status and let them sort it out in their own books.
