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It's Too Hot For Some Planes To Fly In Phoenix (npr.org)
In Phoenix on Tuesday, temperatures were forecast to climb as high as 120 degrees Fahrenheit, causing more than 40 American Eagle regional flights out of Phoenix's international airport to be canceled. NPR reports: American Airlines said in a statement that the Bombardier CRJ aircraft used on some shorter routes have a maximum operating temperature of 118 degrees. For bigger jets, the threshold is higher. The carrier says that, for example, Airbus aircraft have a maximum operating temperature of 127 degrees and that for Boeing, it is 126 degrees. As USA Today reports: "Extreme heat affects a plane's ability to take off. Hot air is less dense than cold air, and the hotter the temperature, the more speed a plane needs to lift off. A runway might not be long enough to allow a plane to achieve the necessary extra speed." Bianca Hernandez, a meteorologist with the National Oceanic and Atmospheric Administration, tells NPR that Phoenix is seeing an unusually strong high-pressure system, which is causing the soaring temperatures.
And that's about 49c for the rest of the world.
Time for the city of Phoenix to submit a federal DOE grant to install “goddamn steam” catapults to solve this problem and specify it to be coal fired will be a sure fire way to get approval.
The same phenomenon that allowed hot-air balloons to first lift man to the heavens now grounds him.
Happiness in intelligent people is the rarest thing I know.
Ernest Hemingway
I'd rather be dead in California than alive in Arizona.
-Lucille Bluth
Except all those airports that already route around heat. And the airplane engineers. And probably a bunch of people that work at airports. And airplane nerds. Etc. You get it. I think.
This is one effect of global warming no one foresaw.
Uh, it's actually a pretty well-known issue. Lots of flights in the Middle East tend to be scheduled at night or in cooler parts of the day to avoid such problems. Larger planes with more powerful engines can often cope with higher temperatures, but it's a problem for less powerful planes that can't accelerate enough to get off the ground with a short runway.
It's a known issue. But so far not a common-enough one to extend runways or do expensive plane redesigns.
This actually isn't all that uncommon around the world, at least to varying degrees.
Hot air, at high(er) altitudes is less dense, which will affect the performance of an aircraft to various degrees. The usual effect is that reduces the aircraft's MTOW (Maximum Take Off Weight). If it drops below a certain point, it's either uneconomical to fly the plane, or it can't carry enough fuel to do its job.
Many years ago, Air Canada used to fly to India using Airbus A340s. At certain times of year, it was hot enough in Delhi that they could not take off with sufficient fuel to do DEL->YYZ direct, and instead they would have to make a technical stop in Turkey to refuel the aircraft. This is also one of the reasons why most long-haul international flights fly in and out of Delhi at night. The air is cooler, giving the airliners better performance.
...si hoc legere nimium eruditionis habes...
Planes full of big fat sweaty Walmart shoppers, oozing grease instead of perspiration.
Nothing but June Gloom this year
https://en.wikipedia.org/wiki/...
Nothing new or myterious. High altitude airports (i.e. Denver) struggle with it all the time. Helicopters, in particular, have to pay close attention to DAlt. A friend told me an entertaining story of spending a week trying to get a chopper to take off from a plateau in Nairobi... combination of a weird pressure change and a heat wave.
Log in or piss off.
If the issue is really air density then how do CRJ planes take off from Denver? Assuming that this page has the physics correctly accounted for then the density of air at Phoenix (331m above sea level) at 49C is 1.059 kg/m^3 whereas the air density in Denver (1600m) is only 0.9978 kg/m^3...and that is if you assume the same air pressure - the density in Denver will actually be a lower than this because the pressure is less.
Perhaps one way to design around this would is to build a longer runway but if that is how they coped in Denver it seems strange that they did not do this in Phoenix given that the effect is far smaller for temperature vs. height so the extension required would be less and 49C temperatures while extreme do not seem to be beyond imagining for Arizona where the record is 53C.
darned millennials, thinking that history began when they woke up two hours ago
Waiting to fly at night is one solution. Another solution is to lighten the load, by limiting the number of passengers, or carrying less extra cargo. Shorter flights can still take off in the heat since they have less fuel to weigh down the aircraft.
I believe in global warming, got solar panels, hopefully a model 3 someday. The non-stop slashdot stories about global warming is going to cause the end of the world as we know it, is a bit much.
All airplanes have performance charts that you use to calculate takeoff distance, single engine climb gradients, etc. It's not that the airplanes won't technically fly, probably they simply don't have performance data that goes that high. Probably not a big problem in Canada.
The reason they might not bother in Phoenix is most of the time, it isn't a problem. Also it isn't a problem for the bigger jets with bigger engines, it seems, just the small ones. Well those are a somewhat new phenomena. 20 years ago if you wanted to do a jet a 737 was about as small as they got. You either used that or went with a prop plane for really short routes.
The last big expansion to Sky Harbor was in 1989, before those little regional jets were a thing.
Yep, I was flying into Phoenix 20-some years ago and they were bumping people before boarding acting like the flight was overbooked. I was surprised when I got on the plane and we took off 1/3 full. I think it was a DC-10. I also remember the turbulence on approach to Phoenix being bad from the thermal convection over the desert.
The article is sort of right. What matters more is density altitude, the effective density based on temperature and air pressure. But that's not to say other aspects of the plane are not rated for that temperature because they would then exceed some internal temperature based on temp rise above ambient.
And this is why we need better passenger rail,
Yeah. Good luck with that in the heat.
Have gnu, will travel.
If they can't fly at those temperatures, then they must not be soaring temperatures.
Phoenix has only had three previous days with a temp of 120F or higher, all occurring in 1990 or later. Such temps were not recorded there any other time since 1890s.
buillshit.
over 20 years ago it was hotter in Phoenix, 122 degrees.
second of all, jet aircraft regularly operate in parts of the world that get hotter than that
There used to be special hot&high versions of an aircraft, with somewhat overpowered engines. They don't make this kind of aircraft anymore because too powerful engines are not economical.
"It's such a fine line between stupid and clever" -- David St. Hubbins, Spinal Tap
It also might be time for diet.
Offloading passengers on hot days is normal practice. Some people get pissed off, and you have to compensate them, but at least you make something on the flight. Cancel it altogether and you make nothing.
Good song.
My Other Computer Is A Data General Nova III.
did you also tie an onion to your belt because it was the style at the time?
High temps hurt performance, but no jet magically loses the ability to fly at one specific temperature. They get grounded because they haven't been tested and certified above a certain temp.
over 20 years ago it was hotter in Phoenix, 122 degrees.
Yes, also related to global warming. Local temperatures are a noisy signal on top of a gradual rising trend.
4 out of 5 doctors approve: https://i.redd.it/wfbt456v0wqy...
I was in Phoenix when they closed the airport due to temperature. I think it was 1990. The problem was their printed charts for how much runway they needed for a certain temperature only went up to about 120F and it was over that, so legally (or insurance-wise) they couldn't fly.
Used to love watching F105's taking off at Nellis in summer, Booom! Water injected would add X amount pounds of thrust to get the lead sleds moving fast....
So yes, they can fly, but airlines are in the business of making money with getting passengers somewhere as a secondary consideration.
In those hotter places they have planned for it and they know they can make a return.
I can understand flying away from Phoenix. But why would anyone choose to live there or go there in the first place? All they have to offer is HEAT. Excessive amounts. Avoid at all costs.
Not going to argue as the GP probably misremembered. However temperature is measured as ambient air temperature, and in the shade.
A runway in direct sunlight is likely to heat the air above it, providing there's no wind continuously replacing the air mass. It'd be interesting to work out by how much.
Human being should do something immediately before it is too late http://williamreview.com/im-vi...
http://williamreview.com/
...in the shade. Not on a runway that is by the very definition of what a runway has to be like is right in the glaring sunlight, with airplanes pushing their hot exhausts right across it.
One might imagine that temperatures could probably be a bit higher in those circumstances.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
You owe me a keyboard and an explanation to my boss.
Could you at least put a NSFW next to it?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
And it's cheaper and more comfortable for the passengers, too, while allowing the train service to still operate at a fat profit.
It takes longer? Yes. But realize that you can travel in a sleeping wagon for the price of a sardine can ticket on a plane. Yes, that still takes 8 hours instead of 2, but it's 8 hours you have to sleep anyway. Check in at 9pm, sleep in your own cabin with your own toilet and your own washing facility, wake up refreshed, take half an hour or hour at your own leisure to refresh, put on fresh and clean clothing, enjoy a decent breakfast and the morning paper if you're so inclined, then emerge at 7am from the train, refreshed, clean and with your clothing in perfect order, ready for your day.
Anyone who ever took the early plane to be somewhere at 7am knows in what condition you arrive there...
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Unless the runway length is too short for the reduced performance, pilots care about the Density Altitude, more so aloft at the altitude they plan to fly. It also affects:
Reduced rate of climb.
Increased TAS (but same IAS) on approach and landing. TAS = true airspeed, IAS = Indicated airspeed
Increased landing roll distance.
https://en.wikipedia.org/wiki/...
And from a FAA safety pamphlet:
Why Does Density Altitude Matter?
High Density Altitude = Decreased Performance
The formal definition of density altitude is certainly correct, but the important thing to understand is that density
altitude is an indicator of aircraft performance. The term comes from the fact that the density of the air decreases
with altitude. A “high” density altitude means that air density is reduced, which has an adverse impact on aircraft
performance. The published performance criteria in the Pilot’s Operating Handbook (POH) are generally based on
standard atmospheric conditions at sea level (that is, 59 oF or 15 oC. and 29.92 inches of mercury). Your aircraft will
not perform according to “book numbers” unless the conditions are the same as those used to develop the published
performance criteria. For example, if an airport whose elevation is 500 MSL has a reported density altitude
of 5,000 feet, aircraft operating to and from that airport will perform as if the airport elevation were 5,000 feet.
Just another day in Paradise
That's not how hot air balloons work! The cold surrounding temperatures are the soaring temperatures. It's hot surrounding temperatures that are the dropping-like-a-brick temperatures.
Ezekiel 23:20
I live in Las Vegas, and we're getting the same high triple-digit temperatures and on top of that most of the Las Vegas valley is at least 2000 feet above sea level vs Phoenix being around 1000 feet. This difference would cause Las Vegas' density altitude to be worse than Phoenix, yet I've heard of no cancelled flights out of Mc Carran airport...
THANK YOU, Edward Snowden!! Americans owe you a debt of gratitude (whether they know it or not..)
In the early 1980s, when I was in the Air Force, I worked on jets in Victorville, California.
One hot day (it was only 115 F or so), a buddy of mine brought a fancy digital thermometer with him because he was curious about how hot it was where we worked.
It was 140 degrees.
So yeah, the difference between shade temperature and "on the concrete" can be pretty stark.
The Urban Heat Island effect is most of that - up until 1965, Phoenix was a minor city, and didn't get much past 100,000 until 1950 or so.
Adding people and buildings makes areas a LOT hotter.
All potential pilots learn about "density altitude" in ground school. https://en.wikipedia.org/wiki/...
Yes, but by the time you got across the street, said onion had turned into onion rings.
Vintage computer games and RPG books available. Email me if you're interested.
Amtrack first class (sleepers) costs far (think 5x) more than an equivalent airplane ticket. Takes _days_ longer to get there.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
I'm not questioning your statement but I'm struggling with this a bit. If I have a runway long enough for a 747 to take off on, for a regional jet, it's essentially infinite. I think part of the issue here is that the planes are not certified to fly at these temperatures regardless of runway length.
So for the last 100 years, or 0.0000002 of known temperature information http://www.climate4you.com/ima... we have a local high. I hate to break it to you, but your sample size is completely meaningless, regardless if you get a +5 on slashdot or not.
If you disagree, please post your argument. (-1, Overrated) isn't your personal censorship tool for views you don't like
Hot air is less dense than cold air
If hot air can hold more water vapor than cold air, how is hot air less dense?
It's not the length of the runway, it's the speed rating of the tires.
The hotter it is, the faster the plane has to roll before it can rotate. At some temperature, that speed exceeds the speed rating of the tires.
I'll believe their defunding the empty, money losing, Amtrak lines when I see it. Amtrak is pork. They surely should defund it.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Thank you. Sorry I can't mod up.
As I said in another reply, one of the limits is the speed rating of the airplane's tires. At a constant weight, as density altitude increases (due to being high above sea level, or at a high temperature) the speed at which the airplane has to roll before it can rotate increases. At some high temperature, the V rating of the tire is exceeded, so that even with an infinitely long runway you wouldn't be able to take off.
In that case you might be able to reduce the weight of the airplane, or simply wait for the temperature to drop...
I can just picture United dragging people out of the airplane and throwing them onto the tarmac until the airplane is light enough to take off. ;-)
The freeways were built in the 1950s. Back when gas taxes more than covered all road costs, as they did for 60+ years, until fuel economy improvements changed it. The net is still gas taxes paying for buses and rail.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Wow. No wonder your air transportation system can get away with treating their customers like terrorists by default, you don't have alternatives.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Distances are just much greater. You canna change the laws of physics.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
the fallacy of asserting the consequent has been committed twice in that post
Still, most reasons to travel (at least for business trips) are within 1000 miles.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
I hate to break it to you, but your sample size is completely meaningless, regardless if you get a +5 on slashdot or not.
I hate to break it to you, but you're an idiot who doesn't understand statistics and can't follow a conversation.
Specifically, the sample size doesn't matter when you're disproving a claim that something happened in the 1960s that didn't actually happen in the 1960s.
Fanatically anti-fanatical
Not in my experience. But I live in CA, many business people from the midwest will tell you their location is better because the trips are shorter, but I grew up there, so not buying it. Even midwest to 'coast' is about 2000 miles, more or less.
Also note: Even at 200 mph the time penalty for train at 1000 miles is pretty bad. Less now, with the shitty airport situation, but the 200mph train is in Germany, so.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
The feds have been using the fund to beat-up the states for decades.
The states should just increase their own gas taxes and we'll just have to write off the federal money. Once they get their hands on it, we're fucked anyhow. Needs more starving, cause what we've been doing is anything but. Far too much money in DC.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Again, the time penalty dwindles to zero when you can get a sleeping cabin on a train for the price of a sardine can seat on a plane. Provided of course that you can travel by night.
Because in the end, I have to be at the destination by 7am and could either fly 4-6am or use the train from 10pm the day before to 6am, I actually gain time when using the train. Because they have WiFi there now, and I have the room to work sensibly while being inside.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
The fastest Amtrak train, would be lucky to get you from Boston to DC in that timeframe. And the sleeper will cost _many_ times more than the airplane seat, I'm not even sure they have them on that train.
Anywhere outside BostiYorkadelphia and it's simply 'no'.
Coast to coast is about a 6-9 hour direct flight. Even on Schnellbahn that would be a 20 hour ride, assuming no stops and a fairly direct line. If we built those rail lines, they would go broke and everybody knows it.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Ad homonym does not further the discussion. AC was saying that his flight was grounded in 1967, not that it was over 120F. As others have stated on this thread, the less powerful planes have lower maximum temperature operating thresholds where they get grounded, so it is entirely possible that AC's flight was grounded due to a high but less than 120F temperature due to the flight being on a turboprop or even a regular prop (not sure what was flying commercial in 1967).
That said, my post still correctly indicts yours:
"Phoenix has only had three previous days with a temp of 120F or higher, all occurring in 1990 or later. Such temps were not recorded there any other time since 1890s."
To be correct: Humans in the last 127 years have only recorded three days over 120F in Phoenix, however, 127 years is virtually meaningless in the scope and scale of global temperatures. Even 2000 years of data is hardly probative.
If you disagree, please post your argument. (-1, Overrated) isn't your personal censorship tool for views you don't like
If you disagree, please post your argument. (-1, Overrated) isn't your personal censorship tool for views you don't like
Why should anyone bother? You're just going to spout the same idiocy again.
Fanatically anti-fanatical