Questions tagged [visibility]

The maximum distance at which objects can be seen.

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Are ILS approaches taught as part of instrument rating?

Are ILS approaches taught as part of instrument rating? What categories specifically? CAT I? CAT II? CAT III A? CAT III B? CAT III C?
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What does "half of the horizon circle" means?

The definition of Prevailing Visibility is: "Prevailing visibility is the horizontal distance over which objects or bright lights can be seen and identified over at least half of the horizon ...
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What is Tendency of RVR?

What does tendency of RVR (Runway Visual Range) mean and why down and up have the same values? This is from AWOS(Automated Weather Observing System)
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What are the Requirements for the implimentation of Low Visibility Procedures at an airport?

So I was wondering if the RVR at an airport is reported above CAT I conditions for eg 1400 Meters etc but the Visibility is 50 to 100 Meters then would the pilots carry out non instrument approach or ...
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How is Horizontal Visibility and RVR related and how does it affect the Low Visibility Operations? [duplicate]

So on my foggy landing the METAR 9 minutes before the touchdown stated Horizontal Visibility as 0000 and RVR 100 whereas the metar 21 minutes after my landing stated Horizontal Visibility 0100 and ...
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How can a touchdown zone RVR report for one runway be different than the rollout report for the runway going the opposite direction?

I saw an RVR report in KSEA where 16C was 800 1200 1800 (touchdown zone, midpoint, rollout), and 34C was 1800 1200 300. I always thought the same scatterometers used for the rollout side on runway as ...
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What is the daytime visibility from within a cloud?

I ask this question from the context of formation-flying, such as during WW2. What is the visibility in a typical cloud during daytime? Can you lose your wingman right away? Were you at serious risk ...
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Why is mid point RVR given?

I cannot understand why mid point RVR is issued and what's the significance of it
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What is the difference between mist and haze in terms of relative humidity?

I am an aviation meteorologist and I struggle to distinguish the two of them.
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Why is the position of the pilots' head (eyes) so important?

From this question: What are these Lights on Center Holm between Windows on the A320? I learn that the pilots' eye position is important. Enough to justify an extra piece of equipment. But why? Can't ...
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Is an area of localized reduced visibility considered to be a cloud?

If there an area containing visible moisture in an otherwise clear sky and that area of visible moisture is transparent is it considered a "thin cloud" or simply a "localized area of reduced ...
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What is the difference between RVR and visibility?

What is the difference between Runway Visual Range (RVR) and visibility? Looking at the definitions, both RVR and visibility tells the pilot whether they have enough visibility to land on the runway ...
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Why are there no emergency flight rules in place to prevent IFR-certified helicopters, operating under special VFR, crashing in low visibility (IMC)? [closed]

In modern times, engineering allows humans to do everything: Drive in fast cars or trains, diving into the deep sea, and even going to space. Which is a great thing indeed. But when it comes to ...
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Why do helicopters crash in low visibility (IMC)? [closed]

There are no known direct eyewitnesses of the crash of helicopter flight Sikorsky S-76B N72EX with 9 people on board, including Kobe Bryant. However, there are many earwitnesses who heard the ...
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With current technology, why is there still increased separation between aircraft and delays in low visibility conditions?

Since most (if not all) commercial aircraft are equipped with inertial and satellite/GPS navigation, why is increased separation between aircraft necessary? Can't controllers immediately identify the ...
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How useful is skyscrapers and high buildings lighting to get a visual reference for pilots by night? (not obstruction lights, just general lights)

I would like to know how useful is skyscrapers and high buildings lighting to get a visual reference for helicopter and small planes pilots by night in cities like New York. This is different from ...
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Why is autolanding ILS a thing, but not autotakeoffing ITS? [duplicate]

In this answer to the question of why zero-visibility landings are legal and routine but not zero-visibility takeoffs, the poster makes the following point: When an aircraft lands in near zero ...
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What are the consequences of turboclair system on restriction due to turbulences?

A turboclair system basically consisted of jet engines used to warm the air around the runway and dissipate the fog. I understand that better visibility due to less fog allows less-well-equipped ...
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Why can't pilots manually fly a low visibility approach instead of using auto land?

Pilots have instruments that help them land. But in low visibility they are required to use auto land. Why can't they rely on their instruments at those times?
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From how far away are the navigation lights of a large airliner typically visible? [duplicate]

I live about 22 miles away from one international airport in the UK, and just over 30 miles away from another. When I spot aircraft lights at night and check for corresponding aircraft on ...
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3 answers
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Why is there no instrument taxi system for low-visibility operations?

In one of the comments on this answer regarding ILS category IIIc operations (or, rather, the lack thereof), it's mentioned that There is no [radio] guidance for taxiing except the pilot's vision. ...
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How good is the ground visibility by a moonless night In the Grand Canyon?

My night flying experience is limited to light-polluted coastal southern California. When flying over low-population countryside on a clear, moonless night, do the stars provide enough light to ...
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What is acceptable visual cue at Decision Height when performing CAT II approach?

For CAT II approach, the decision height is below 200ft but not lower than 100ft with RVR of 300m. In this case, if the aircraft is at 100ft above the ground, should the captain of that aircraft be ...
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14 votes
7 answers
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Why can a plane land in zero visibility conditions but not take off in zero visibility?

After waiting hours for a flight departure delayed because of heavy fog, I wonder why planes can perform an instrument landing with no visibility, but cannot take off without a minimum visibility.
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What does METAR show when actual RVR is below the reporting minimum?

RVR is measured between 50m and 1500m (ICAO). When the actual RVR is below 50m, what does METAR show?
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Can the touchdown RVR be replaced by the midpoint or rollout RVR?

When there are three RVRs equipments in place and an ILS approach chart minumum for the runway simply says "RVR 800m" without any additional notes, is the touchdown RVR the only controlling RVR? If so,...
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What constitutes "the lights delineating the runway"?

ICAO defines RVR as "The range over which the pilot of an aircraft on the centerline of a runway can see the runway surface markings or the lights delineating the runway or identifying its centerline."...
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Does the definition of visibility take object size into account?

Overall, visibility is the distance at which objects may be discerned. Does this definition take into account the size of the objects? Obviously large objects can be seen from farther away than small ...
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1 answer
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What is the relationship between temperature, dew point and the formation of clouds?

What can you infer from the temperature / dew point values in this METAR? EGJG 121630Z 09012KT 9999 SCT006 15/14 Q1015 I understand the temperature is 15 degrees and the dew point is 14, and I ...
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Do any aircraft windshields have anti-reflective coatings?

Anti-reflective coatings are used in many applications to reduce glare and prevent double images. Double images in particular are a concern because of the several layers involved in a cockpit window. ...
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Why don't aircraft (commercial and military) use reflective visor windshields?

Just like those used on an astronaut's helmet, these reflective visors can help in better visibility when facing the sun (or any bright light source). But the windshields of most aircraft (commercial ...
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Can I spot the drones watching me in the sky with naked eyes? [closed]

To quote John Oliver: "Yemen, home to 26 million Yemeni people, and 27 million American drones." While these numbers may be slightly exaggerated I started to ...
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Is white/brown-out effect hazardous during the landing roll out?

Landing on unpaved runways or runways covered by snow or dust causes a white/brown-out visibility restriction. Does it disrupt the pilot's visibility during the roll out in a fixed-wing aircraft?
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9 votes
1 answer
499 views

What is an Enhanced Vision System?

I was reading something at work that said the company has installed an Enhanced Vision System on the aircraft. FedEx Express added Enhanced Vision Systems to 250 aircraft, which will greatly ...
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19 votes
2 answers
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How is the visibility at airports measured?

What tools are being used by airports to measure visibility precisely? Do we have some kind of tools on aircraft as well for measuring visibility?
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4 answers
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Is there a database of airport ceilometer raw data?

I am interested in obtaining raw ceilometer data, to test some cloud/aerosol layer identification algorithms. Is this type of data freely available or will I need to ask for it directly from the ...
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2 answers
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Which airports have ILS Cat IIIC?

Are there any airports with ILS working CATIIIC? What do the charts for this procedure look like? Is there a missed approach procedure?
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3 answers
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Why are aircraft external lights round, not tear-drop shaped?

I saw this image of a Cessna 172's tail posted on another question and it made me wonder why the beacon light is basically a cylinder, and not a more aerodynamic, teardrop shape? Image source
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Are zero visibility landings a possibility for the future of commercial aviation?

Airports usually close or slow down activities in fog conditions, e.g. this seems to be a significant problem in winter at Delhi airport. Large commercial aircraft would be able to land with no ...
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24 votes
8 answers
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How do pilots see at night if airplanes don't have front lights?

How can pilots identify threats ahead of them if they don't have front lights like cars?
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2 answers
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How can landing in zero visibility be safe?

I recognise that autoland and ILS can enable landings in zero visibility, which I presuppose in this question (e.g. in this video where touchdown happens around 5:22). Further, suppose that the fog is ...
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34 votes
5 answers
10k views

What happened during this foggy landing?

Several years ago, I was flying from the USA to Buenos Aires. That's a very long flight, and it was overnight for us. When I woke up it was early in the morning and we were over Argentina. I don't ...
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1 answer
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Are red obstacle lights near an airport required to be lit during the day?

What are the FAA Beacon Light Requirements for 80 foot tall High Mast Poles Near an Airport? Specifically, do the RED beacon lights need to be illuminated 24 hours per day? Or, do they only need to ...
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7 votes
2 answers
10k views

What is the definition of visibility as seen in aviation weather reports?

If you look at the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) page for Washington D.C., Reagan National Airport (KDCA), it shows hourly weather ...
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