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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.
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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.
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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.
Arizona overall isn't a hot state, it's just Phoenix which happens to reside in a valley. If you actually go south to Tucson, it's generally about 5 degrees cooler, and to the north lies Flagstaff, which this year had the longest duration ever for its popular snow skiing resort being open (from October til May.) It also snows much of the year at Four Peaks, which is about a 1 hour drive from Phoenix.
You may as well say that California is a hot state because of Death Valley, which is always hotter than Phoenix.
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.
I have a few guesses as to why they don't have this problem in Denver but they do in Phoenix. One you point out is that Denver likely has longer runways. Why not extend the runways in Phoenix then? Likely because this happens so infrequently that they did not want to go through the expense of extending the runway. I got to talking to an engineer that works on airports. As I recall the runways are dug something like 30 feet into the dirt and filled with concrete. That's a lot of concrete to make up for a few hours of inconvenience every few years. This is not your typical concrete and the surface is engineered for keeping traction in all kinds of weather. Every extra foot of that runway must be very expensive.
Another possibility is that airports in Phoenix are older and with improvements in optimizing airframes over the years for some norm the margins got slimmer. This means that over time the airplanes needed longer runways but the airport couldn't extend the runway even if they wanted to. Old airports tend to have the city build up around it and pen it in from expanding.
It could also be that nothing changed physically but the rules under which they operate did. It could be that somewhere in the world an airplane didn't quite make it off the runway in the heat so the FAA decided that the rules on the safety margins had to be changed. It's quite possible every aircraft that wanted to take off could do so, and in the recent past the FAA would have allowed it. But because of a desire to maintain an abundance of caution the FAA grounded those flights.
I recall someone pointing out that we have not seen a commercial jet crash that resulted in fatalities since 2001. We've seen big planes crash since then but no deaths. We've seen people die in plane crashes but not on a major airline on a regularly scheduled flight. I think the FAA would like to keep it that way as long as possible.
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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.
I found a cool source:
https://www.pilotsofamerica.com/community/threads/max-operating-temperature-for-airplane.104126/
According to these guys, there is probably no physical limit that absolutely prevents the CRJ from operating safely above 118 degrees, given runways that are long enough for the gross weight. The problem is that pilots and airlines are not allowed to use the laws of physics, such as the ideal gas law, to calculate the required runway length to takeoff at a given weight and temperature. Instead, they are required to use the official performance data published by the OEM. The official performance data is printed in the FAA-approved Airplane Flight Manual as a series of graphs, and for airliners the same data may also be available in some computerized form. The graphs are only printed up to a certain temperature, so if the ambient temp. exceeds that limit, there is no way to calculate the required runway length.
For at least some planes, it may be possible to obtain officially sanctioned "expanded performance data," aka. charts that extend into higher temperatures, but it's often not economical to shell out extra fees to get this data.
On the radio today, they said this heatwave (7 days of 49C IIRC) is a one in 200 year thing and hasn't happened since last year.
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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.