Training for limited visibility
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Training for limited visibility
Can anyone who tell me what pilots are typically trained to understand about "RVR" today?
Do training materials and instructors specifically emphasise that if ATC passes an RVR value, this does NOT tell them “The range over which the pilot of an aircraft on the centre line of a runway can see the runway surface markings or the lights delineating the runway or identifying its centre line.” (ICAO RVR definition)?
Do training materials and instructors specifically emphasise that if ATC passes an RVR value, this does NOT tell them “The range over which the pilot of an aircraft on the centre line of a runway can see the runway surface markings or the lights delineating the runway or identifying its centre line.” (ICAO RVR definition)?
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Steve: I've operated LVO's for 35 years, so the training is a long time ago. In those days, LTN, there indeed was a man in a tower to the side of the runway and he counted the lights along the far edge to assess RVR. This was passed to the tower and to the crew. Later automatic transmisometers were introduced and these sit to the side of the runway at 2 or 3 points depending on the rwy length. The towers were removed. I do not know their precise dimensions of the auto sensors, i.e. height & space, but they transmit and receive a light beam and have some fancy circuits to convert to RVR. Their calculation is defining to the RVR given to the crew.
They have practical problems, as I have been subjected to. They are supposed to sit above a clear concrete platform. They are <2m agl. and near the often moist grass.
Some years ago, on a CAT 1 only a/c, meaning we needed 550m, I was given 450m RVR by the tower via these auto devices. I was holding at 10nm 3000' and could see the whole runway. The fog back was very very shallow, perhaps engulfing the auto sensors. However this figure is governing and is recorded, so ATC nor the pilot can cheat and it would be a licence threatening event to disobey them. Frustration? You bet, especially as we were in a CAT 3 a/c but the airline was not certified, yet. Luckily another local operator was arriving and would perform a CAT 3 autoland. I asked to be put 4.5nm behind him on finals. 4nm being the approach limit. I hoped his landing would blow the fog bank away to >550m just before I hit 4nm and so I could continue. I also asked for a PIREPS by the landing pilot. That is a report as the pilot lands of his assessment of the RVR. i.e. pilot's eye height over the CL, as you mention. Before ATC could intervene he said "the RVR is well in excess of what your giving (450m), I called "visual" and ATC said, "Land". Reported to DFO &never heard another word.
Sometimes auto systems do not make life better and more convenient. They do make to easier for the poor bloke who had to spend a night 'in the tower of doom'. Does the automatic system really reflect ICAO definition? You'll need to ask a higher authority.
For take off we are allowed to taxi to the runway and count the C.L lights and self-assess. Difficult on landing.
Were we trained in this aspect? No. Were we trained in the art of fudging? No. Once, finally, a bar-room conversation saved my day.
They have practical problems, as I have been subjected to. They are supposed to sit above a clear concrete platform. They are <2m agl. and near the often moist grass.
Some years ago, on a CAT 1 only a/c, meaning we needed 550m, I was given 450m RVR by the tower via these auto devices. I was holding at 10nm 3000' and could see the whole runway. The fog back was very very shallow, perhaps engulfing the auto sensors. However this figure is governing and is recorded, so ATC nor the pilot can cheat and it would be a licence threatening event to disobey them. Frustration? You bet, especially as we were in a CAT 3 a/c but the airline was not certified, yet. Luckily another local operator was arriving and would perform a CAT 3 autoland. I asked to be put 4.5nm behind him on finals. 4nm being the approach limit. I hoped his landing would blow the fog bank away to >550m just before I hit 4nm and so I could continue. I also asked for a PIREPS by the landing pilot. That is a report as the pilot lands of his assessment of the RVR. i.e. pilot's eye height over the CL, as you mention. Before ATC could intervene he said "the RVR is well in excess of what your giving (450m), I called "visual" and ATC said, "Land". Reported to DFO &never heard another word.
Sometimes auto systems do not make life better and more convenient. They do make to easier for the poor bloke who had to spend a night 'in the tower of doom'. Does the automatic system really reflect ICAO definition? You'll need to ask a higher authority.
For take off we are allowed to taxi to the runway and count the C.L lights and self-assess. Difficult on landing.
Were we trained in this aspect? No. Were we trained in the art of fudging? No. Once, finally, a bar-room conversation saved my day.
