Questions tagged [weather]

Weather means the atmospheric conditions, including wind, temperature and precipitation, in a specific area at a specific time.

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34 votes
3 answers
6k views

What happens when an airplane gets struck by lightning?

I know that they certify airplanes for lightning strikes (at least some of them anyway), but does it cause any damage to the airplane or to the electronics? Are there any required inspections if an ...
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10 votes
3 answers
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How Earth's rotation affect flight times? [duplicate]

How much does Earth's rotation affect flight times in going East or West, and how could you calculate if zero winds?
43 votes
5 answers
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How common are cancelled landing attempts?

I recently traveled from Stansted, UK to Skavsta, Sweden with Ryanair, and was informed that depending on the weather (it was very foggy), we might end up landing at Arlanda (~150 km from Skavsta) ...
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39 votes
6 answers
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How do pilots foresee turbulence?

During a normal flight at cruise speed and altitude, amid the delicious airline meal and the enjoying a latest movie, all of a sudden the seat belt sign turns on. Then a few seconds later we enter ...
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21 votes
1 answer
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Why are some contrails longer than others?

I've often noticed that planes flying on more or less the same track, headed in the same direction leaves different contrails. By different I mean how long they stay visible and the length of them. ...
20 votes
4 answers
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Can I use cellular data to receive in-flight weather on my iPad?

I would like to use an iPad for preflight planning. Can I also use the iPad to check weather while I'm en route?
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17 votes
2 answers
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How does radar detect turbulence and wind speed?

In an answer to a questions about turbulence this answer mentioned that aircraft use radar to help detect the most turbulent areas of a storm so that pilots can avoid them. How does radar do this? ...
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12 votes
4 answers
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Why don't we get more user-friendly weather reports than METARs?

This question is not about how to decode METARs or what software or tools can be used to decode METARs. It is about why we are still using METARs today. Given that we have smartphones with video ...
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9 votes
2 answers
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Why is there a disparity in the conversion from runway visual range (RVR) to statute miles?

TBL 5-4-1 in the Aeronautical Information Manual (AIM) provides conversion from RVR to visibility in statute miles. I've reversed the first two columns from the AIM table to allow for comparison of ...
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28 votes
3 answers
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What causes a plane's wing tips to leave a small white vapor trail?

What is the source for what looks to be small trails of smoke or condensation sometimes coming from the very tips of a jet aircrafts wing tips?
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22 votes
2 answers
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What is turbulence, and how does it happen?

I'm not a pilot, so I always wonder when I'm flying why does it happen... Is it because of bad weather, or something else?
21 votes
2 answers
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When is pre-heating a piston engine important, and how does one pre-heat correctly?

As temperatures here in New York plunge toward (and below) freezing it's time for those of us without nice heated hangars to start thinking about pre-heating our aircraft before we turn the key. ...
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13 votes
2 answers
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To receive an SVFR clearance, does the airport need to be reporting IFR conditions?

If conditions at a towered airport are not IFR, can pilots request a special VFR clearance? For example, at a Class D airport, ceiling 1300 broken, 10 sm visibility is technically too low to remain in ...
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12 votes
1 answer
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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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8 votes
1 answer
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Do airlines continue operating in the vicinity of a hurricane?

Have hung around some of the aviation interest groups (like airliners.net) and tried to research this but haven't found very clear answers. Typically when a hurricane (tropical, peak wind-speed in ...
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28 votes
6 answers
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Do jet contrails impact weather?

Do jet contrails impact weather at the ground?
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25 votes
3 answers
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Why would ASOS have a caution for Low Density Altitude?

I did my initial training in a high altitude area, where it got pretty hot in the summer, so I'm not at all surprised when I hear an ASOS announce: Caution: Density Altitude (a few thousand above ...
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20 votes
1 answer
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How does NOAA's P3 Orion safely navigate hurricanes?

I've been watching NOAA's P3 Orion fly though Hurricane Matthew a bit on Flight Radar 24. Looks a bit like this for the curious: source It's the only plane actually in Hurricane Matthew. What I'm ...
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17 votes
5 answers
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Are sun's UV rays more harmful on an airplane at high altitude?

Most airplanes fly at >30k feet, way into the stratosphere / mesosphere where sun's UV rays aren't filtered by lower atmosphere layers. If the windows of the plane are open and the sun is shinning ...
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16 votes
3 answers
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Can commercial airliners fly over hurricanes?

When Patricia was making landfall yesterday I opened up Flight Radar 24 to see if there were any planes flying around or near it. As I had expected, there were a couple of storm watching planes near ...
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15 votes
2 answers
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How is an on ground lightning strike test conducted?

Whenever a design company is obtaining an STC for an aircraft (Supplemental Design Certificate) for an electrical installation, one of the required tests to obtain the STC is a lightning strike test. ...
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11 votes
3 answers
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How do I determine the best altitude to fly for fuel economy?

If you fly low, air is dense so you can get more thrust from your engines, but you get more drag. On the other hand if you fly higher you have less drag but the output of engine decreases as well. So ...
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11 votes
1 answer
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How can a pilot anticipate cloud formation?

I read a few articles and a book about cloud forming, but I didn't really understand it. Can anybody explain in simple terms how clouds form? As a pilot, what factors that contribute to cloud ...
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9 votes
1 answer
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What are the different kinds of de-ice fluid?

When frost adheres to the airplane or it is snowing, you need to make sure the airplane is clean when you depart. You've probably seen the trucks spraying aircraft in the winter before departure, but ...
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8 votes
1 answer
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What sources of weather are approved by the U.S. National Weather Service?

Part 135 and (I believe) Part 121 operations all have a requirement to use a source of weather that has been approved by the U.S. National Weather Service: §135.213 Weather reports and forecasts. ...
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7 votes
2 answers
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What are the criteria for "variable" in METAR reports?

Regarding variable wind direction in METAR reports, what are the criteria for VARIABLE when the authority uses "VRB"? An Advisory Circular mentions the authority uses "V" when the wind direction ...
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3 answers
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How do pilots decide whether to circumnavigate bad weather?

How does an airline pilot decide in the air whether to circumnavigate or fly through bad weather visibly looming ahead and/or displayed on the weather radar ?
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4 votes
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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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50 votes
6 answers
16k views

Why was my flight cancelled due to bad weather while other flights were not?

I'm stuck in Frankfurt. I missed my connection due to a delay. I was rebooked, but this new flight was also cancelled due to bad weather. About 30 percent of all flights were cancelled today. ...
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45 votes
4 answers
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My windsock is erect, what does this mean?

I know that airport windsocks are calibrated to reach full erection at a particular wind velocity. At half that speed, the first half of the windsock should be erect and the second half should droop ...
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29 votes
3 answers
7k views

How can I tell how far I am from a cloud?

So the other day as I was flying, I started to wonder: All pilots should be familiar with basic VFR cloud clearance requirements in 14 CFR 91.155 (and if not, then go study now!). When flying piston ...
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25 votes
4 answers
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Does temperature affect takeoff performance?

A few days ago, a Copa flight from Porto Alegre to Panama was delayed from noon until 12:30 AM. The company explained that the high temperature (about 40 degrees Celsius) would require a longer runway ...
24 votes
3 answers
6k views

What are the weather requirements to log an instrument approach?

So let's assume that I'm the sole manipulator of the flight controls in an aircraft in which I'm rated and that I fly an instrument approach. What weather does the FAA require (assuming that I'm not ...
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22 votes
5 answers
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Why is one of two parallel runways sometimes closed in foggy weather?

A few times, when flying into SFO, me and my fellow passengers were informed that due to foggy weather one of two parallel runways there is closed, causing delays. So, a few questions: Why can only ...
21 votes
1 answer
32k views

Why is mist abbreviated BR on METARs and TAFs?

The abbreviation for a condition of mist is BR on METAR and TAF reports. How did mist end up getting abbreviated as BR?
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21 votes
1 answer
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What does a dollar sign mean in a METAR?

Look at this METAR: KLOU 151553Z 21005KT 10SM CLR 13/M01 A3044 RMK AO2 SLP309 T01281011 $ What does the dollar sign mean?
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16 votes
1 answer
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Does the "Maintenance Indicator" sign on a METAR imply we can't trust it?

As explained in this Q/A: What does a dollar sign mean in a METAR? The presence of a Dollar Sign ($) at the end of a METAR is included when an ASOS/AWSS detects that maintenance is needed on the ...
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14 votes
1 answer
7k views

Why is a TFR issued when barometric pressure exceeds 31.00 InHg?

Why does a barometric pressure above 31.00 InHg trigger a TFR?
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14 votes
2 answers
7k views

What do multiple slashes in METAR mean?

The current METAR for Stanstead in the UK says: EGSS 031520Z AUTO 29011KT 9999 FEW021/// //////TCU 07/02 Q1022 I do not know how to interpret the /// and //////. From what I remember multiple ...
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13 votes
6 answers
2k views

How can an airplane land if a hail storm damages the windshield?

I understand hail can be very damaging to an aircraft, in particular to the engines and windshield. In the event that a windshield becomes cracked so that visibility is impossible, can pilots pop out ...
13 votes
3 answers
11k views

How are thermals found?

As far as I understand glider pilots like to look out for thermals. I assume that when you are in one, you can perceive that and you can make roughly sure to stay in it. But what if you're not in a ...
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12 votes
5 answers
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Why are pressure levels raised on warm days?

As I'm studying for the PPL knowledge exam, I had the following note: Pressure levels are raised on warm days and the indicated altitude is lower than true altitude. (source: AOPA) But I don't quite ...
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12 votes
1 answer
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What is METAR and how is it read?

I was reading an article about TAM Airlines Flight 3054 crash and I saw the following: METAR SBSP 172200z 35008kt 7000 -ra Bkn008 Ovc070 15/14 Q1018 SBSP 172200z 35008kt 7000 -ra Bkn008 ...
11 votes
1 answer
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What do the different colors of weather stations indicate on SkyVector?

In this particular map from SkyVector, what are the meanings of the different colored circles, and for the different amounts of 'fill-in'? It's obvious by hovering over them, that they are weather ...
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11 votes
2 answers
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Which precautions should I take when flying in very cold / hot weather?

What are the important precautionary measures to take when a flight (either GA or airliners) is operating in extremely cold (e.g. -10°C or below) or extremely hot (e.g. 40°C or above) weather ...
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10 votes
2 answers
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What is Tropopause height, and how is it determined?

I have seen the term "Tropopause height" used in a flight navigation plan. What is it and how is it determined?
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10 votes
4 answers
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How well can an airplane which is tied down be protected from a blizzard?

I've been in the very early stages of shopping for my first single engine plane. That has made me more thoughtful about the environment in which a given plane is stored. So the recent blizzard in the ...
10 votes
2 answers
1k views

What FAA sources of weather information can pilots use to mitigate the risk of flying in icing conditions?

Pilots flying under the FAA jurisdiction have many official sources of weather information available to them. Specifically as it relates to icing conditions, what official sources of weather ...
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9 votes
2 answers
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How are landing minimums decided?

How are landing minimums decided for a flight? Does the captain make the decision depending on weather conditions or is it preset for each airport?
8 votes
1 answer
2k views

How do the FAR's define a cloud?

If you're talking about a big puffy cumulus cloud it's pretty obvious. But from where I am right now, looking up I see grey sky from horizon to horizon. But visibility at the surface is good. All ...
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