Reported Visibility and approach ban
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During the flare, you'll be looking along parallel to the runway and will only be able to see 350m.
One only gets caught once .. the first time. Thereafter, one has a heightened respect for ground fog.
One only gets caught once .. the first time. Thereafter, one has a heightened respect for ground fog.
During the flare, you'll be looking along parallel to the runway and will only be able to see 350m.
One only gets caught once .. the first time. Thereafter, one has a heightened respect for ground fog.
One only gets caught once .. the first time. Thereafter, one has a heightened respect for ground fog.
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O.O who would have thought one can go missed from 50 ft? That's what the go around is all about, isn't it? Any time you're not happy GO AROUND. There's no such a rule as one must land once below DA but there's a rule saying any time visual reference is lost go missed. Simple and very effective.
9.0G,
Yes, simple and effective- also expensive and suprisingly high risk.
Of course you should go-around if visual reference is lost, but the idea of the regs is to make that as rare an occurence as possible.
Yes, simple and effective- also expensive and suprisingly high risk.
Of course you should go-around if visual reference is lost, but the idea of the regs is to make that as rare an occurence as possible.
Exactly, the regs are there to try and ensure a landing or an 'early' missed approach. What I am saying though is that if the tower reported visibility is below the required, you are entitled to continue to the OM or equivalent.
If at that position you are actually visual with the runway and your assessment is that you have the required visibility for the approach then you should continue bearing in mind that at ANY point you lose the required visibility you should execute a missed approach whether that be at 900ft or 50ft.
If at that position you are actually visual with the runway and your assessment is that you have the required visibility for the approach then you should continue bearing in mind that at ANY point you lose the required visibility you should execute a missed approach whether that be at 900ft or 50ft.
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Forgotten the numbers exactly, but isn't the required vis/RVR supposed to represent pilot eye height over the rwy C.L. i.e. 10m-ish. The RVR transmittometers were supposed to automate this measurements, but we all know their limitations.
Now the average ATC tower is 30m high. How can this relate to pilot eye height over rwy? If the pilot has the required visual reference above DA surely that it is appropriate to be able to make a decision to land. I agree about low level fog, but the same is true; if at DA and you have the visual reference you can decide to land. A mate at GRO did this, and at 50' it all went very dark and a G/A ensued. It still did not make the decision at DA wrong.
Now the average ATC tower is 30m high. How can this relate to pilot eye height over rwy? If the pilot has the required visual reference above DA surely that it is appropriate to be able to make a decision to land. I agree about low level fog, but the same is true; if at DA and you have the visual reference you can decide to land. A mate at GRO did this, and at 50' it all went very dark and a G/A ensued. It still did not make the decision at DA wrong.
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Hi Rat 5,
Because the RVR measuring devices are located to the side of the runway, (on the grass normally) and stand about 2m high.
Runway visual range - Wikipedia, the free encyclopedia
There was a Vanguard crash at LHR in the 60s (ASN Aircraft accident Vickers 951 Vanguard G-APEE London-Heathrow Airport (LHR)), caused by attempting to do a manual landing in fog. After that accident the rules changed to stop other keen aviators from going down to "have a look".
If the reported RVR is below minima, and you have not passed the OM (or equivalent point or 1,000 ft AAL) - even if you can see through the shallow fog 10 miles out, then it's what we in the trade call an "Approach Ban".
Edit: See Follow up/ Safety action note 4.
"The system whereby no positive approval of an operator's weather minima is required to be given by the Ministry is unsatisfactory. It gives power whilst withholding responsibility. Positive approval or disapproval should be required."
So you may thank these guys for the increased operating safety by taking the decision to make the approach or not, by the OM (or equivalent position).
Now the average ATC tower is 30m high. How can this relate to pilot eye height over rwy?
Runway visual range - Wikipedia, the free encyclopedia
There was a Vanguard crash at LHR in the 60s (ASN Aircraft accident Vickers 951 Vanguard G-APEE London-Heathrow Airport (LHR)), caused by attempting to do a manual landing in fog. After that accident the rules changed to stop other keen aviators from going down to "have a look".
If the reported RVR is below minima, and you have not passed the OM (or equivalent point or 1,000 ft AAL) - even if you can see through the shallow fog 10 miles out, then it's what we in the trade call an "Approach Ban".
Edit: See Follow up/ Safety action note 4.
"The system whereby no positive approval of an operator's weather minima is required to be given by the Ministry is unsatisfactory. It gives power whilst withholding responsibility. Positive approval or disapproval should be required."
So you may thank these guys for the increased operating safety by taking the decision to make the approach or not, by the OM (or equivalent position).
Last edited by rudderrudderrat; 26th Apr 2012 at 10:51.
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Precisely, they are 2m high. I've often been on rwys with dew and fog drifting over the grass surrounding the transmittometers. The rwy was crystal clear. When I asked what the RVR was ATC replied the vis was 10k's +, but indeed the RVR was quite low. I've also had an approach ban on a RWY with RVR's 450m. Crossing the OM en-route to the hold we could see the whole rwy, but RVR's are RVR's. Fortunately there was a local CAT 3 operator following us. We set up 4nm behind him and asked for PIREPS. At all time down the G/S we could see the whole rwy. The landing captain reported vis "well in excess of what ATC was giving." We call field in sight and landed, no problems.
There was also an occasion at Luton, when the had electronic RVR's and also the old wooden tower by the threshold. The RVR's were <CAT 1. WE were visual. We asked for a visual RVR from the wooden tower. This confirmed the truth of much higher RVR's at pilot eye height and we landed.
And I'm still sure the definition if required RVR is quoted as being at Pilot eye height and is Xm's above the rwy. IMHO the transmittometers are not fool proof.
And the original question here was about ATC met vis, which when >3km's is surely not an exact science.
There was also an occasion at Luton, when the had electronic RVR's and also the old wooden tower by the threshold. The RVR's were <CAT 1. WE were visual. We asked for a visual RVR from the wooden tower. This confirmed the truth of much higher RVR's at pilot eye height and we landed.
And I'm still sure the definition if required RVR is quoted as being at Pilot eye height and is Xm's above the rwy. IMHO the transmittometers are not fool proof.
And the original question here was about ATC met vis, which when >3km's is surely not an exact science.
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Wiz, aviation is expensive but my primary concern is safety. Let the bean-counters crunch the numbers. A GA from 50 ft isn't more dangerous than one from a bounce or having no flare at 50 ft during CAT III b. Just my 2 cents. I treat it practically rather then academically.
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It is not that they do not trust...
It is more that they read the Italian AIP and used the same calculation method. The reference is AIP Italia AD 2 LIMJ 1-9. Within the local flying restriction they require a 50% increase of the aerodrome operating minima because the runway strip is not in conformity with ICAO.
It is more that they read the Italian AIP and used the same calculation method. The reference is AIP Italia AD 2 LIMJ 1-9. Within the local flying restriction they require a 50% increase of the aerodrome operating minima because the runway strip is not in conformity with ICAO.
9.G,
Saftey is my priority to- no a GA from 50ft isn't more dangerous than a bounce- they are BOTH higher than normal risk occurences that should be kept to a minimum.
Saftey is my priority to- no a GA from 50ft isn't more dangerous than a bounce- they are BOTH higher than normal risk occurences that should be kept to a minimum.
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they are BOTH higher than normal risk occurences that should be kept to a minimum.
We can go on and crack each other's heads open with sharp rhetoric however the point of this discussion would go amiss, methinks. How bout exposure of the paying folks to a higher risks during training flights? Don't you think passengers have the right to know the level of the risk exposure? I bet if it was compulsory to inform passengers about training flights no revenue pax would ever buy a ticket on a commercial flight with a cadet under training. You would agree it's safer to train pilots outside commercial operations and once ready release them to fly commercially. Well, again I wish we lived in the ideal world. Whatever you do as a skipper is you call what matters is the outcome.
Last edited by 9.G; 27th Apr 2012 at 12:22.
It is more that they read the Italian AIP and used the same calculation method. The reference is AIP Italia AD 2 LIMJ 1-9. Within the local flying restriction they require a 50% increase of the aerodrome operating minima because the runway strip is not in conformity with ICAO.
