transmissometer U/S
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transmissometer U/S
If a transmissometer is out of service how does this effect CAT 1, 2 , 3 landings ? Any ideas where to get accurate source of reference. HAPPY NEW YEAR !!!
Join Date: Jan 2007
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If Transmissometers are u/s then factored met vis may be used under certain circumstances. Tables to factor the vis are normally provided by the operator. The factors normally depend on DAY/NIGHT and runway lighting.
Join Date: Oct 2003
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Having had just this a couple of years back at a UK airfield and we ended up diverting. We were happy and legal to complete the approach based on our ops manual however the ATC guy wouldn't clear us for an approach based on his ops manual (MATS 2?). Stalemate, burning fuel in the hold waiting for a ground engineer to fix the thing.... only he took too long to get to the airfield.... something about fog on the roads. 
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Flew into Dublin one night with it reporting overcast at 100 feet, the visiblity was fine, just low cloud with LVPs in force.
Anyway they cleared the aircraft ahead for a CAT II approach (R28 is CAT III), thought nothing of it untill another aircraft ahead asked was CAT III available, to which approach replied that the Mid Point transmissometer was U\S and he could only offer CAT II. There's noting in our OPS manuals about this, so I don't know what reference he was using.
IR
Anyway they cleared the aircraft ahead for a CAT II approach (R28 is CAT III), thought nothing of it untill another aircraft ahead asked was CAT III available, to which approach replied that the Mid Point transmissometer was U\S and he could only offer CAT II. There's noting in our OPS manuals about this, so I don't know what reference he was using.
IR
According our Ops Manual for Cat 2/3 if the touchdown transmissometer is u/s the mid point value may temporarily be used if the State approves this - not sure how you find out if State do so!
