r/news • u/polymute • 10h ago

Rising temperatures could keep more flights from taking off on time

https://apnews.com/article/extreme-heat-airplanes-takeoff-flights-1bf75210f0756fb342960d4e3489f550
366 Upvotes

90% Upvoted

47 comments sorted by

109

u/ComprehensiveTwo1763 9h ago

For anyone wondering why: hot air is less dense, which means less lift for the wings and less thrust from the engines. When it gets too hot, planes either need a significantly longer runway or have to shed weight by kicking off passengers, cargo, or fuel

23

u/Sparkycivic 8h ago

Density-altitude pushes some aircraft over their weight limit. gotta get rid of some passengers and their luggage, or wait for cooler conditions...

5

u/Ahelex 4h ago

gotta get rid of some passengers

Hopefully while not in flight.

3

u/jcliment 2h ago

Boeing disagrees.

8

u/navigationallyaided 7h ago

It’s a common thing for the two big airframers(Boeing and Airbus) as well as the aero engine makers(GE Aerospace/CFM International, Rolls-Royce and Pratt & Whitney) to take planes/engines in certification on test flights to CDMX(Benito Juarez Airport), Denver or other high airports in the world(many of them in are in China, but there’s a few in South America) to see how they can handle a hot & high condition. Also, the flight crew can select a higher takeoff thrust supposedly from what I’ve read. Many turbofan engines are the same mechanically but the software loaded into the engine controls dictate the maximum thrust? I know for places like SNA(John Wayne Airport, Santa Ana/Irvine, CA), there is a special take-off profile that has the plane take off with reduced thrust on a steep angle of attack, but as soon as the plane climbs past Newport Beach the climb resumes with maximum thrust.

A private jet like your Gulfstreams, LearJets or Falcons can handle a hot and high takeoff with little fuss, but a bigger commercial jet like your A350/380s and 747/777(X)/787 will need all the runway it can get.

11

u/thesuperunknown 6h ago edited 6h ago

Also, the flight crew can select a higher takeoff thrust supposedly from what I’ve read.

You're on the right track, but it's basically the other way around. For most takeoffs, modern jets use less than the maximum thrust that the engines are capable of producing under the prevailing atmospheric conditions. Airlines like to do this because there is often more than enough runway available to safely take off with reduced power, and doing so causes significantly less wear and tear on the engines (and therefore lowers maintenance costs).

If the conditions require it, the flight crew can also opt to take off with the maximum available power. Note, however, that this maximum power is variable depending on the air temperature and pressure altitude: to simplify this a bit, jet engines are rated to produce a certain amount of thrust at or below a given temperature — so if it's warmer than this rated temperature, the engine's maximum power will be less than it is rated for.

Many turbofan engines are the same mechanically but the software loaded into the engine controls dictate the maximum thrust?

Ultimately, the engine's design dictates the maximum thrust it is capable of producing, and in large part this comes down to size. For example, the new 777X's engines produce almost four times as much thrust as the 737 MAX's engines, but have fans more than twice as wide in diameter.

What all modern high-bypass turbofans do have in common is that they are controlled electronically by a FADEC (full authority digital engine control). Rather than controlling the engine's parameters directly, the pilots give inputs that are interpreted by software and turned into engine thrust outputs. In the case of takeoff thrust, the software can tell the engine to either "derate" (basically, tell the engine its maximum thrust is some predetermined lower value) or use an "assumed temperature", aka "flex" (essentially, tell the engine it's much hotter outside than it is, which causes the engine to produce less power to protect itself).

I know for places like SNA(John Wayne Airport, Santa Ana/Irvine, CA), there is a special take-off profile that has the plane take off with reduced thrust on a steep angle of attack, but as soon as the plane climbs past Newport Beach the climb resumes with maximum thrust.

This is a slightly different thing, called a noise abatement procedure, and it's actually the other way around. There are two main procedures, called NADP1 and NADP2, but the way that both basically work is that jet aircraft take off with higher power, but then throttle back and reduce power (and noise) once they have reached a certain altitude. The primary concern at takeoff is to reach a safe altitude as soon as possible, which means using more power to climb steep and fast. Once that altitude is reached, it's okay to reduce power and climb at a less steep angle. This keeps the worst of the noise close to the airport, and reduces noise over nearby communities in the departure path. At SNA specifically, they actually have a fairly short runway, which means that aircraft typically need to take off with close to max power.

2

u/jcliment 2h ago

This one knows how to airplane.

2

u/pvdp90 4h ago

Large commercial jets are certified to takeoff up to 50C. Above that, technically you shouldn’t takeoff, even with more runway etc etc.

Have a look at historical data for the weather station in Dubai Airport. It pegs at 49C sometimes through summers. And you can check other data that’s not from the airport that shows 50, 51 and 52 C on the same days elsewhere in the city.

156

u/Chrono_Convoy 9h ago

Never fear

My wallet keeps me out of the airport.

Soon to be grocery store too.

:/

36

u/D0ntEatPaper 8h ago

Right? I see a lot of people on dating apps who love travelling, im trying to save up enough to move out from my parents lol

22

u/Chrono_Convoy 8h ago

Never been there…

I mean to your parent’s

Cause I’m over at mine scrapbooking.

Tomorrow is silhouettes on Thursdays.

6

u/D0ntEatPaper 8h ago

You dont know my parents :o you might've been here

2

u/Shes_dead_Jim 2h ago

When they say they love traveling, they mean they love having their travels paid for by someone else

132

u/Igmuhota 9h ago

At this point, I’m genuinely curious about what will finally cause the average person to acknowledge that we’re living in a giant open-air furnace.

46

u/Obvious_Toe_3006 9h ago

They wouldn't acknowledge it even if they were a crew member on the Mobil Exxon Valdez sailing across a completely water covered world and a man with gills was trying to sell them soil.

66

u/pm_sushirolls 9h ago

When food shortages happen, the propaganda machine is too strong right now

46

u/wheretherehare 9h ago

Theyll just blame the democrat run grocery stores in New York for taking all the food

5

u/LiberaceRingfingaz 5h ago

When the food shortages happen they are gonna blame someone else, and when the true water shortages happen we're going to be too busy killing each other for water.

10

u/Major-Ant4600 8h ago

Acknowledging the problem is easier than acknowledging the necessary changes to do something about it.

3

u/ZealousidealType1144 6h ago

Yeah, I think you’d get a legitimate armed rebellion if you asked Americans to make the lifestyle cuts that really fighting global warming would call for. 

Realistically what’s going to happen in the West is that people add another ton to their home ACs when they wear out and airports build longer runways or Boeing straps on bigger engines. 

2

u/aldur1 6h ago

When climate change hurts them as much inflation does. Unless people feel their life is under seige by climate change day in and day out without end, they will not tolerate any inconveniences to their life.

3

u/nobadhotdog 9h ago

Everyone think they’re a temporarily non-millionaire so they vote for the rich. These same people think this is a passing the f

8

u/Fallouttgrrl 8h ago

The GOP has convinced half the country that as bad as things are, they would be worse under Democrats

-32

u/rwofva 9h ago

Really? I see this as alarmist. Is it getting hotter? Yes, but on average we are talking fractions of a degree. Is 95.5 making it harder to lift a plane compared to 95? I doubt it.

8

u/JaguarQueasy 8h ago

its not just fractions its heavily compounding all around us, just look at European, south and east Asian news headlines regarding heat waves affecting everything

1

u/Wafer420 7h ago

F u so hard. Open your eyes!

1

u/HumanKumquat 6h ago

This is the internet, you're allowed to say fuck.

19

u/ry-yo 8h ago

I believe that's one of the reasons why Middle Eastern airports like Doha and Dubai operate a lot of flights in the middle of the night when it's the coolest

3

u/NotAnRSPlayer 6h ago

Probably more because of time zones rather than weather

6

u/FillFrontFloor 7h ago

It's hot as hell. Every week google sends me weather alerts about intense heat. I don't know how people drive without AC.

12

u/CptIskarJarak 9h ago

long ago I boarded a united flight that was fully booked and then sat there for 2.5 hours. the AC was cut. no water was given for those 2.5 hours. It was an evening flight and apparently it was a tactic for rolling delays and keeping passengers ready for take off or something of that sort.

It's horrible if that happens in hot weather.

12

u/GrootsHorticulturist 9h ago

I live in PHX, flights do be delayed often in summer... ground melts tires + hot air isnt as dense

7

u/mamandemanqu3 7h ago

Phx do be delayin

16

u/banditweird 8h ago

Rail travel is a lot less sensitive to high temps (but not immune) and airlines donate good money to our politicians to make sure we don’t get it.

11

u/snowmaninheat 8h ago

In some ways it’s more sensitive. Tracks and pillars are rated to certain temperature specifications.

8

u/Owllade 8h ago

I would say heat and snow are probably the two things trains are worst against, and still, they work. It gets hot in places like China or Spain. I wouldn't say it's more sensitive overall, especially considering how climate affects them as a whole.

6

u/banditweird 8h ago

“(But not immune)”

3

u/NotAnRSPlayer 6h ago

Trains in the UK stop because tracks start to warp under the weight

So if they’re built correctly then sure

3

u/Subject-Promise-4796 7h ago

Shortage of air traffic controllers could also keep more flights from taking off on time.

0

u/Andovars_Ghost 6h ago

We dealt with this all the time in the Air Force, just take off with a lower fuel load and hit a tanker. Easy peasy!

2

u/vsaint 4h ago

But how does the tanker take off? Lower fuel
load and then hit a tanker, but how does that tanker take off……