CAT 3 auto land
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CAT 3 auto land
What is the point in having an RVR of 75m with a DH of 0ft? Who in their right mind is going to go around once they have hit the deck with spoilers deployed because they observe less than 75m? Am i missing something here?
Am i missing something here?
On a Cat IIIb (no DH) approach there is no requirement for you as the pilot to check/confirm/verify by eyeball ( or "observe" as you put it ) that you've got 75m RVR as you touchdown, or do anything about it if by chance, on landing, you just so happen to notice the vis less... wizofoz explains why below.
Last edited by wiggy; 10th Aug 2016 at 14:39.
It is the vis required to be reported prior to the ABP in order to continue the approach PAST the ABP.
There are no visual reference requirements after that in a CatIIIb (no DH) approach.
Other low vis approaches have different visual reference requirements at minima (e.g, Cat IIIa requires three center-line lights), but that is different from needing to determine that a particular RVR is available after the ABP.
There are no visual reference requirements after that in a CatIIIb (no DH) approach.
Other low vis approaches have different visual reference requirements at minima (e.g, Cat IIIa requires three center-line lights), but that is different from needing to determine that a particular RVR is available after the ABP.
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The 75m RVR is to allow you to taxi off the active runway (and then get lost on the fog). Also, once the spoliers come up you are totally committed so there will not be a go-around. Ladtly, if you land and find the actual viz is zero, you just stop and wait for an improvement.
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Low vis taxi....
I've had two Cat 3 arrivals where once we exited the runway, we had no idea of where we were. Both times ground control sent a follow-me out to lead us in. One was well done, took us right to the right gate, the second time we watched the follow-me roll into a ditch. We, fortunately, did not follow him into the ditch.
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The 75m RVR is to allow you to taxi off the active runway
Back in the early days of autoland I remember a lengthy discussion/disagreement about minimum vis and it was driven by the fire-services. They argued the minimum vis was for them to reach the runway within the required minimum time. I do not know the outcome of those discussions, just what the various limits are now.
Back in the early days of autoland I remember a lengthy discussion/disagreement about minimum vis and it was driven by the fire-services. They argued the minimum vis was for them to reach the runway within the required minimum time. I do not know the outcome of those discussions, just what the various limits are now.
CAT111B autoland we use an Alert Height of 100' RA.
No redflags / warnings and 'land 3' displayed continue with the autoland, no visual reference necessary.
DH is not used.
No redflags / warnings and 'land 3' displayed continue with the autoland, no visual reference necessary.
DH is not used.
The 75 metre figure was arrived at in the early discussions about CAT III limits at Heathrow.
The Fire Service stated they would have difficulty finding an aircraft in anything less.
The Fire Service stated they would have difficulty finding an aircraft in anything less.
Spoilers have nothing to do with 'No Go-Around' on a Boeing. You can 'Go-Around' until reverse is selected- same as a previous poster mentioned on the Airbus.
