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from the commerce-collides-with-science dept.
The Associated Press reports via KTAR-FM in Glendale, Arizona
At Phoenix Sky Harbor International Airport, American Airlines regional jets sit on the tarmac as American Airlines says seven regional flights have been delayed and 43 have been canceled because of a heat wave as temperatures climb to near-record highs Tuesday, June 20, 2017, in Phoenix.
[...] It's the air density.
Hotter air gets thin, making it harder to take off and land safely, mostly for smaller jets. That's what has kept some planes grounded in Phoenix this week where temperatures have been pushing 120 degrees. Airplanes take off and stay aloft because of lift, the force from the movement of air underneath the plane's wings that push it upward.
"As air warms up, it expands and there's fewer molecules to be under your wing", said Lou McNally , professor of applied meteorology at Embry-Riddle Aeronautical University. With less lift, "you need more of everything. You need more thrust to take off. You need more distance (on the runway) to take off. You need more distance to land. You need more speed to land. It gets to a point for some aircraft that it gets just too much", he said.
High heat also means a plane climbs at a lower rate, said pilot Patrick Smith, author of the book "Cockpit Confidential".
To compensate, planes have to generate more thrust or power and have larger wings. Smaller jets that generate less thrust, like Bombardier's CRJ regional jets, which have a 118-degree limit at Phoenix's elevation, are more likely to be stuck in the heat.
At Dubai International Airport and other Gulf airports, which are used to hot weather, many flights--but not all--arrive at night and early morning to get around the heat problem. Gulf carriers also tend to operate longer flights using larger planes that aren't as limited by high heat.
[...] Airlines can take other steps when the temperature climbs too high. They can lighten the plane's load by selling fewer seats--a tactic American Airlines is using in the Phoenix heat wave--or reducing cargo. They can take off with less than a full tank of fuel and then stop somewhere cooler to refuel.
(Score: 2) by VLM on Wednesday June 21 2017, @09:21PM (6 children)
I pulled the plates (heres phoenix) and thats true to a substantial level
http://aeronav.faa.gov/d-tpp/1706/00322ad.pdf#nameddest=(PHX) [faa.gov]
Phoenix longest runway is a hair short of 11500 and Denver has a record long 16000 feet.
One other limitation I can think of is ground pressure. Cheap asphalt might get too mushy to hold up a jet.
One thing for sure is this problem is long solved, there are plenty of jets in the middle east, etc. They might have screwed up by failure to correctly specify in Phoenix but that's not the problem of the aerospace industry, works fine in Riyadh S.A.
I'm not sure you can really trust anything in mainstream media WRT fake news. This whole story is pretty smelly.
(Score: 4, Informative) by AthanasiusKircher on Wednesday June 21 2017, @09:37PM (5 children)
(1) I don't know how long the runways are in the Middle East. (2) It's pretty well-known that flights in hot temperatures in the Middle East are often scheduled at cooler times of the day or at night because of precisely this issue. You could easily figure that out if you bothered to look. Oh wait -- it's in the freakin' summary.
Sorry, but what the heck are you talking about? The flights were actually cancelled. That's verifiable. What insane conspiracy angle do you have about why that happened that the "mainstream media" is hiding from you?
And look -- it happened before in 2016 [azfamily.com], 2013 [businessinsider.com], was debated in 2011 [cbs5az.com], and there were various advisories and warnings about this just for Phoenix in various other years. What's your explanation for all of this history?
(Score: 2) by frojack on Thursday June 22 2017, @12:55AM (4 children)
Because these stories weren't mentioned last year at this same time when those same flights were canceled for the same reason during the annual hot-spell. Where were these stories then?
But then Your Lord and Master Obama was still President and he had already Promised the 100 billion annually for projects in the third world, even though he had no source or destination for a single dollar. So of course we weren't allowed to know of canceled flights then.
No, you are mistaken. I've always had this sig.
(Score: 2) by Justin Case on Thursday June 22 2017, @02:22AM
Bingo! Even news that is absolutely true can be "fake" because it distorts or conceals the whole picture.
I was at an event with 10,000 protesters. (My estimate.) The local newspaper didn't like our cause so they didn't want to show the size of our support. Instead they showed a picture of a mom and her two kids. True that they were there, but totally missed the point. So in the message it conveyed, false.
(Score: 2) by AthanasiusKircher on Thursday June 22 2017, @03:05AM (1 child)
Excuse me? Are you mistaking me for an Obama supporter??
(Score: 2) by frojack on Thursday June 22 2017, @06:47AM
Far be it from me to make you out to be anything .
No, you are mistaken. I've always had this sig.
(Score: 4, Informative) by AthanasiusKircher on Thursday June 22 2017, @03:15AM
Oh, and by the way, there were stories last year. Here's a couple major national news sources like USA Today [usatoday.com], ABC [go.com].
I assume the reason why coverage wasn't as big is because I think only one flight was turned back over it last year, instead of several flights preemptively cancelled this year. If you look at 2013 when more flights were cancelled, there appears to have been more widespread news coverage beyond local networks, etc.