I just flew on this same route on Eva last week and at one point the tailwind speed was 200mph. We were close to or over supersonic relative to the ground for most of the trip; we left like 20 minutes late and arrived over an hour early. The turbulence was pretty rough though; at three separate sections the captain had to make the cabin crew strap in and after the third section like that the captain clearly decided he was done and gunned the engines to take the plane up another 4000 feet. That El Niño effect on Pacific air currents right now is no joke.
The captain clearly decided he was done and radiod air traffic control for permission to go to +4000 ft and gunned the engines to take the plane up another 4000 feet
Or, they asked ATC if they had any idea what might be a smoother ride, and that's what ended up being suggested.
If you listen to ATC radio at all, it's a lot more anecdotal than you'd otherwise suspect, with private planes that fly higher sometimes reporting smoother air at higher flight levels.
Honest question; is there air traffic control over the Pacific?
I guess this was a China to US flight (can't read TFA), so maybe within land based radars?
I'm no pilot, but I assumed over large open water it's pretty much "designated highways" with designated altitudes.
But sure, if permission is needed I think it's implied in the original post that he got clearance to so. If theres more to "doesn't work like that" I'd be interested.
You don't actually need radar to have air traffic control. It's just that ATC can't provide tracking services for the entire route.
Instead, aircraft file their routes in advanced (which are either a series waypoints, or a fixed airway), and pilots occasionally radio in position updates as they progress.
The airspace is still controlled, but without tracking, the separations are much larger. Any two aircraft that might be on the same route or might cross paths have different assigned altitudes, and they must communicate with ATC before changing altitude or route.
Well, I assume he asked ATC and all of the usual stuff, but as an unaware passenger all I know is we climbed and then things got smoother. The engines sound super impressive when climbing.
Note that as a plane burns fuel, its maximum sustainable altitude and its most fuel-efficient altitude both increase. This explains why the pilots did not climb to a higher flight level earlier.
Thank you for putting it that way. I swear if the rest of the world just poked fun at us for using it, we would probably change it. “Awww look honey, the Americans are still using miles and pounds, isn’t that precious..”
The old system is useful for very common things like cooking, because it's a Duodecimal system and you can more easily do fractions in your head. I get it it's funny "the Americans don't like science", but it's actually pretty far from the truth.
I have a habit of measuring ground distance in meters, for example, because I was in the (US) Army and yes we measured those things in meters/kilometers. But other things are not measured like that.
Measuring systems are only useful if they are, well, easy. And some systems are more easy in certain circumstances than others. Which is to say, it's easy to get used to a meter being a pace (tie a meter long string to your ankles).
The metric system is pretty good at that: 1 ml H2O = 1 cm^3 = 1 g, and 1 calorie will increase its temperature 1 deg C (assuming 1 atmosphere pressure, and a certain water temperature).
You hit! From my experience, metric system is best for pharmaceutical calculations, like "how many water need to got 40% alcohol", and it's also extremely important for taste, as in many cases better 38%.
> The old system is useful for very common things like cooking, because it's a Duodecimal system and you can more easily do fractions in your head. I get it it's funny "the Americans don't like science", but it's actually pretty far from the truth.
It's really not. Most of the time, I just convert to grams and use a scale so I can get an actually accurate input quantity. I don't want to think about "heaping" and "leveled" and "packed" and different densities, humidity or uneven distribution within a measuring implement. If I'm going to be putting it on a scale I'm definitely not setting it to ounces.
I think the difference it that I don't have to use a scale. I'm not in a chemistry lab, I'm in my kitchen. Though, I suppose, those are one in the same aren't they.
I'm very very particular about measuring out the exact amount a recipe calls for and putting it all in little dishes before we actually start cooking. But I don't actually have a scale, maybe I'll get one and try it. My wife will probably stop me, because once I get into the details on a particular topic I tend to go overboard.
On the math thing, probably during Christmas when we were trying to stretch a baked French Toast recipe to feed 9 people in stead of 6. Worked great.
Haha, honestly I don't have much of a real opinion on this topic. I do suggest the scale, though. I find I get much more consistent results. Even if it's set to ounces ;) The error bars on "one cup of flour" IME are enormous.
This is making me realize that the error bars really live in the kitchen of the recipe maker.
My french toast is ruined! I measured the exact amount you said! Not realizing that the original cook was using the Larry David measurement system. "Ehhh that's close enough".
I dunno man, I'm rest of the world and my dad uses pounds/feet/miles habitually despite obviously knowing kg/m/km and using SI units professionally (He's a mechanical engineer...). I grew up on metric but eventually learned the conversion factors anyway because it's still in common use.. and for some reason we still measure houses in sq ft and tire pressure in psi...
If you want to get technical, we should be using Mach number or knots since that’s what the world uses for aviation. That being said, the majority of the article’s consumers aren’t technical with this topic :P
Well as long as we're getting technical, Mach number is a unitless aerodynamics term, not a speed. As such, it is only valid in the exact medium that a craft is traveling in and relative to that medium, so here air at the exact temperature and pressure the aircraft is flying at. There is no valid general conversion between speed and Mach number, and things like Mach number relative to the ground is nonsensical.
>There is no valid general conversion between speed and Mach number, and things like Mach number relative to the ground is nonsensical.
Sure, if you also want to say water doesn't freeze at 0C or boil at 100C. In practice if an author casually leaves out the variables needed to calculate ground speed from mach or airspeed, it usually means they're doing engineering calculations set at the ISA standard day model (sea level, 15C, no humidity).
Sure, but it is more relevant to describe aerodynamic properties of an aircraft. Knots can have a similar problem (look up indicated airspeed). But I guess you’re right, we should be using ground speed knots in this instance.
If you ask a pilot, ground speed only really is important for calculating ETA. Everything relevant to flying is a relative number since atmospheric density is fluid.
It depends what geoid model you use, and once you go down that rabbit hole it depends on the local gravitational field which is affected by things like mountains, not only the centrifugal effect.
For a sailor in the 16th century, assuming a sphere was perfectly adequate when combined with 1 degree = 60 nautical miles.
The origin of nautical miles is from 16th century sailors.
And 21st century aviation doesn't need anything more accurate than WGS84. The people who need custom geoid models and local coordinate systems are surveyors.
It's the longitude that changes. Note that lat parralels are horizontal, but you measure on which parralel you are, so you measure north-south position.
It's the curvature of the earth that changes local radius - greater at the equator, less at the poles. Hence the arc distance of a fixed angle changes also.
I believe you're thinking of distance between lines of longitude which converge at the poles and are at maximal seperation at the equator.
I was referring to the arc distance (surface distance) between lines of latitude which don't converge to zero but do get a little smaller closer to the poles (due to the lesser minor radius of the ellipsoid shape to the earth - oblate sphereoid, squashed sphere, not a perfect ball, etc.)
In my PPL training you either use the latitude-axis (X) on the equator only, which you will not have in your maps when flying in US or Europe. The alternative is to use the longitude axis (Y) which will always be 1° = 1 NM which can then be readily used in a "what is my groundspeed in knots per hour and what is my ETA" - so to the best of my knowledge you are correct. Then again I am no native speaker.
But it really helps you as in you are able to pick any distance you want to fly on the map and by moving your fingers to the Y axis roughly guess the distance within a few seconds. Even in a very small cockpit and with turbulence. So i absolutely see the need for this with relation to navigation.
Feet, nautical miles, statutory miles, and meters are all part of the United States Customary Units.
"Imperial units" is ambiguous and can refer to many different sets of units all sharing the same name. US Customary units use SI as a baseline for measuring based on physical constants, and standardized conversions from them to units very similar to what was conventional. Eg, since the meter is defined by the distance light travels in a vacuum for the duration of 1/299,792,458 second, and the US defines an inch to be exactly 2.54 cm, any refinement to the speed of light inherently changes the length of an inch. 12 inches equals a foot, a mile equals 5280 feet (exactly 1609.344 meters), and all these things are based on physical constants. Nautical miles are defined as exactly 1852 meters, which is approximately 1.15 miles.
Just like "metric" can refer to CGS or MKS, "imperial" can refer to... well, whatever you want. But usually in the US when we say "imperial", we mean statute miles as the mile unit, not nautical miles.
"Pounds of fuel" are used when, after declaring an inflight emergency, ATC requests information for on ground fire rescue along with number of souls on board.
>Are feet and NM not part of the standard Imperial units of measure?
In addition to the other replies you're getting here, the US for instance does not use imperial units, despite what many people on the internet believe. Imperial units are used by the UK (hence the term "imperial"). The US uses "US customary units", which sometimes overlap with UK units, and other times have the same name but are different. An imperial gallon is quite different from a US gallon, for instance, but imperial and US inches are the same.
This one always seems silly to me. If you wanted to use SI units, it'd be meters/second. Or maybe km/sec if you were going really fast. Having hours in your velocity units means you've got a dumb 3600 in there if you wanted to do any math with acceleration.
I guess the real benefit to km/h is that it allows people to act superior without knowing it's just as dumb as imperial units.
It's odd to think that one's adherence to an arbitrary measurement system makes one "modern", but it would be more interesting to examine why someone assumed that something "modern" was obviously better.
I'm not meteorologist, but love aviation, so dig these things deep.
For me, this case most probably example of Great climate event, which for some reason missed by scientists.
What could trigger it, is light mystery, because even now scientific coverage of Earth is not constantly complete, and in 1862 existed whole regions without good scientific network (now, only some countries closed for science).
Most probably, reason was some fluctuations of Gulf Stream or Supervolcano.
71 comments
[ 3.4 ms ] story [ 142 ms ] threadThat's not how civil aviation works, but never mind. Sounds like a neat story.
is that better
If you listen to ATC radio at all, it's a lot more anecdotal than you'd otherwise suspect, with private planes that fly higher sometimes reporting smoother air at higher flight levels.
I guess this was a China to US flight (can't read TFA), so maybe within land based radars?
I'm no pilot, but I assumed over large open water it's pretty much "designated highways" with designated altitudes.
But sure, if permission is needed I think it's implied in the original post that he got clearance to so. If theres more to "doesn't work like that" I'd be interested.
Instead, aircraft file their routes in advanced (which are either a series waypoints, or a fixed airway), and pilots occasionally radio in position updates as they progress.
The airspace is still controlled, but without tracking, the separations are much larger. Any two aircraft that might be on the same route or might cross paths have different assigned altitudes, and they must communicate with ATC before changing altitude or route.
¿ʞsɐ noʎ op ʎɥʍ 'oᴎ
I have a habit of measuring ground distance in meters, for example, because I was in the (US) Army and yes we measured those things in meters/kilometers. But other things are not measured like that.
Measuring systems are only useful if they are, well, easy. And some systems are more easy in certain circumstances than others. Which is to say, it's easy to get used to a meter being a pace (tie a meter long string to your ankles).
Anyone have a rhyme for it?
It's really not. Most of the time, I just convert to grams and use a scale so I can get an actually accurate input quantity. I don't want to think about "heaping" and "leveled" and "packed" and different densities, humidity or uneven distribution within a measuring implement. If I'm going to be putting it on a scale I'm definitely not setting it to ounces.
When was the last time you really looked and said, geez, thank the lord I can divide 1lb 14oz into eights really easily in my head?
On the math thing, probably during Christmas when we were trying to stretch a baked French Toast recipe to feed 9 people in stead of 6. Worked great.
My french toast is ruined! I measured the exact amount you said! Not realizing that the original cook was using the Larry David measurement system. "Ehhh that's close enough".
Sure, if you also want to say water doesn't freeze at 0C or boil at 100C. In practice if an author casually leaves out the variables needed to calculate ground speed from mach or airspeed, it usually means they're doing engineering calculations set at the ISA standard day model (sea level, 15C, no humidity).
I replied above, but knots have a similar problem when flying (indicated air speed).
If you ask a pilot, ground speed only really is important for calculating ETA. Everything relevant to flying is a relative number since atmospheric density is fluid.
- 'knots' is faster to say on the radio than 'kilometers per hour'
- the way the world is divided in wgs84, maked it so that 1 degree of latitude equals exactly 60 miles. So that makes quick measurements a bit easier.
What with the Earth being an ellipsoid and not a sphere and all that?
For a sailor in the 16th century, assuming a sphere was perfectly adequate when combined with 1 degree = 60 nautical miles.
The geoid model is the surface of gravitational equipotential and is a "shape of the gravitational field" not a "shape of the physical earth".
If we were discussing 16th century sailors rather than 21st century aviation you might have had a point.
The origin of nautical miles is from 16th century sailors.
And 21st century aviation doesn't need anything more accurate than WGS84. The people who need custom geoid models and local coordinate systems are surveyors.
I believe you're thinking of distance between lines of longitude which converge at the poles and are at maximal seperation at the equator.
I was referring to the arc distance (surface distance) between lines of latitude which don't converge to zero but do get a little smaller closer to the poles (due to the lesser minor radius of the ellipsoid shape to the earth - oblate sphereoid, squashed sphere, not a perfect ball, etc.)
But it really helps you as in you are able to pick any distance you want to fly on the map and by moving your fingers to the Y axis roughly guess the distance within a few seconds. Even in a very small cockpit and with turbulence. So i absolutely see the need for this with relation to navigation.
https://aviation.stackexchange.com/questions/2566/what-is-th...
In my experience, US pilots usually use feet for altitude, but use nautical miles for distance and knots for speed, not standard Imperial units.
[1] https://en.wikipedia.org/wiki/Nautical_mile
"Imperial units" is ambiguous and can refer to many different sets of units all sharing the same name. US Customary units use SI as a baseline for measuring based on physical constants, and standardized conversions from them to units very similar to what was conventional. Eg, since the meter is defined by the distance light travels in a vacuum for the duration of 1/299,792,458 second, and the US defines an inch to be exactly 2.54 cm, any refinement to the speed of light inherently changes the length of an inch. 12 inches equals a foot, a mile equals 5280 feet (exactly 1609.344 meters), and all these things are based on physical constants. Nautical miles are defined as exactly 1852 meters, which is approximately 1.15 miles.
In addition to the other replies you're getting here, the US for instance does not use imperial units, despite what many people on the internet believe. Imperial units are used by the UK (hence the term "imperial"). The US uses "US customary units", which sometimes overlap with UK units, and other times have the same name but are different. An imperial gallon is quite different from a US gallon, for instance, but imperial and US inches are the same.
I guess the real benefit to km/h is that it allows people to act superior without knowing it's just as dumb as imperial units.
I’m curious if changes in the jet stream are correlated/could be used to predict the next “mega” atmospheric river event.
Any meteorologists around who could chime in?
[0]https://en.m.wikipedia.org/wiki/Great_Flood_of_1862
For me, this case most probably example of Great climate event, which for some reason missed by scientists.
What could trigger it, is light mystery, because even now scientific coverage of Earth is not constantly complete, and in 1862 existed whole regions without good scientific network (now, only some countries closed for science).
Most probably, reason was some fluctuations of Gulf Stream or Supervolcano.