will these affects operations? In what ways?

The paint will melt off the jets LOL

The news has been denied by a Meteo office personnel.

Ok, 65C is about 150F for those of us in the US. The actual temperature will be about 45 C / 115 F. The highest temperature ever recorded in the world is about 57C / 134 F. So DXB is not going to hit 65C today.

However, with the humidty the "feel like" temperature is supposed to be near 65C.

Pretty sure that's just the heat index...

65 degree Celsius would be 149 F.

http://www.guinnessworldrecords.com/wor ... mperature/

I'd be highly skeptical of the 65 degree Celsius claim.

kbmiflyer wrote:

Ok, 65C is about 150F for those of us in the US. The actual temperature will be about 45 C / 115 F. The highest temperature ever recorded in the world is about 57C / 134 F. So DXB is not going to hit 65C today.

However, with the humidty the "feel like" temperature is supposed to be near 65C.

But it is a great way to confuse people into thinking the world is ending.

45C is still hugely hot. And from memory is either over or very close to what's considered naturally human habitable. If you're somewhere with working aircon you'll probably be fine. But out on the ramp for hours and hours? People just start breaking at those temps and humidity.

From the pics I have seen, DXB has black pavement on the its taxiways, that's a lot of radiated heat.

And Dubai has an indoor ski slope, too funny.

Hopefully the Emirates fleet won't be too affected, those GE90 engines in particular gulp a lot of air to produce their thrust. It's just a characteristic of being the biggest thrust engines out there.

Even at 45 degrees it's pretty far up the curve for normal operations. Some flights might find themselves restricted in the way airlines like ET get limited out of Addis Ababa, as the hot air is less dense. EK's longest flights might have to take a temporary payload penalty.

kbmiflyer wrote:

65C is about 150F for those of us in the US. The actual temperature will be about 45 C / 115 F.

While this is correct that the actual temperature is probably close to 45, don't forget that temperature readings are always taken in the shade. In the sun and on concrete, the actual human-felt temperature will seem way way higher. So 45 degrees is actually insanely hot.

ZaphodHarkonnen wrote:

45C is still hugely hot. And from memory is either over or very close to what's considered naturally human habitable. If you're somewhere with working aircon you'll probably be fine. But out on the ramp for hours and hours? People just start breaking at those temps and humidity.

45C isn't the end of the world. We hit 45c three weeks ago at my house. Heat index was about 47c. Felt like an oven but people still did their jobs and there weren't reports of widespread health problems.
You are right that heavy exertion is more dangerous but there are other factors. Being acclimated to such conditions over a lifetime makes negative reactions less likely because your body and brain have learned how to function in that environment.

I once read meteorologists in some gulf countries are asked to report a lower high temperature than it really is because if it's too hot legally required water and shade breaks for the construction workers kick in. Airports and other areas where the actual temperature is required use unofficial temperatures. I don't know if this is true or no, but 65 degrees C seems almost unbelievable for prolonged outdoor work. It is, however, perfect football weather.

I was passing through Death Valley a few weeks ago when it was 51C with a slight breeze. Humidity was less than 10% so standing in the shade away from the wind was tolerable, but in direct sunlight or with some wind in my face it was just about unbearable. Like sticking your head into a hot oven.
Once did some cycling there at 52C but downhill only (about a 5500 foot descent, no pedaling) and we kept ourselves wet. Quite nice.

EK has been operating afternoon ULH flights for a couple of years now (JFK and this year LAX). Just wondering how, or if, high temperatures affect a 16 hour LAX flight on a full A380 that is scheduled to take off daily at 3pm (almost hottest time of the day)? As far as I'm aware, there are no payload restrictions on this flight.

Marco wrote:

EK has been operating afternoon ULH flights for a couple of years now (JFK and this year LAX). Just wondering how, or if, high temperatures affect a 16 hour LAX flight on a full A380 that is scheduled to take off daily at 3pm (almost hottest time of the day)? As far as I'm aware, there are no payload restrictions on this flight.

That's interesting!

ikramerica wrote:

45C isn't the end of the world. We hit 45c three weeks ago at my house. Heat index was about 47c. Felt like an oven but people still did their jobs and there weren't reports of widespread health problems.
You are right that heavy exertion is more dangerous but there are other factors. Being acclimated to such conditions over a lifetime makes negative reactions less likely because your body and brain have learned how to function in that environment.

Humidity is critical. Whether you can stay cool or not doesn't depend on temperature alone, but on a combination of temperature and humidity. In more humid air, your sweat doesn't evaporate -- and it's the evaporation that keeps you cool.

"Wet bulb" temperature is the temperature that would be registered by a bulb surrounded by a wet cloth, so that water is evaporating off the bulb. In dry conditions, wet bulb temperature is far cooler than nominal temperature. In humid conditions, it gets much closer. The human body is physically incapable of keeping itself cool through extended exposure to a "wet bulb" temperature of over 35 C/96 F. Acclimation doesn't help with this -- it's just physics.

You can get a 35 C wet bulb temperature at just 36.5 C/98 F nominal temperature if the relative humidity is 90 percent, conditions that usually happen only in tropical storms. On the other hand, if the relative humidity is only 10 percent (typical of intra-desert conditions) then you could have your theoretical 65 C day and the wet bulb temperature would still not be close to 35 C. In Dubai, relative humidity in very hot conditions is typically around 55%. At that level of humidity, to reach a 35 C wet bulb temperature the nominal temperature would need to be 44.5 C/112 F. Sustained outdoor work at or above this temperature without regular indoor breaks would be life-threatening to humans.

(And deeply unpleasant. The best measure of how humans feel humidity isn't RH, but dewpoint. Dewpoints over about 20 C generally feel sticky and nasty. The dewpoint at 44.5 C/55% RH is 33 C, which is just horrible.)

seabosdca wrote:

ikramerica wrote:

45C isn't the end of the world. We hit 45c three weeks ago at my house. Heat index was about 47c. Felt like an oven but people still did their jobs and there weren't reports of widespread health problems.
You are right that heavy exertion is more dangerous but there are other factors. Being acclimated to such conditions over a lifetime makes negative reactions less likely because your body and brain have learned how to function in that environment.

Humidity is critical. Whether you can stay cool or not doesn't depend on temperature alone, but on a combination of temperature and humidity. In more humid air, your sweat doesn't evaporate -- and it's the evaporation that keeps you cool.

"Wet bulb" temperature is the temperature that would be registered by a bulb surrounded by a wet cloth, so that water is evaporating off the bulb. In dry conditions, wet bulb temperature is far cooler than nominal temperature. In humid conditions, it gets much closer. The human body is physically incapable of keeping itself cool through extended exposure to a "wet bulb" temperature of over 35 C/96 F. Acclimation doesn't help with this -- it's just physics.

You can get a 35 C wet bulb temperature at just 36.5 C/98 F nominal temperature if the relative humidity is 90 percent, conditions that usually happen only in tropical storms. On the other hand, if the relative humidity is only 10 percent (typical of intra-desert conditions) then you could have your theoretical 65 C day and the wet bulb temperature would still not be close to 35 C. In Dubai, relative humidity in very hot conditions is typically around 55%. At that level of humidity, to reach a 35 C wet bulb temperature the nominal temperature would need to be 44.5 C/112 F. Sustained outdoor work at or above this temperature without regular indoor breaks would be life-threatening to humans.

(And deeply unpleasant. The best measure of how humans feel humidity isn't RH, but dewpoint. Dewpoints over about 20 C generally feel sticky and nasty. The dewpoint at 44.5 C/55% RH is 33 C, which is just horrible.)

As per the article which triggered all this - it will reach 45-46 degrees @ 90% humidity. How would the wet bulb temperature develop with that?
And does it make sense that it will feel like 65 with that combination of temp & humidity?

Ro

Most performance charts go to 115F or 45C, so north of that figure all bets are off

These temperatures are normal here this time of year, in fact norm around 48C, its the humidity that is making people talk at the moment not normal until later in the summer! I did a night shift a few years ago where DXB experienced the highest over night low of 44.6C!!

In MEL a couple of years ago the temperature was 46C with low humidity, the wet bulb temperature was in the mid 20s. A couple of ULH flights scheduled for the afternoon were delayed until the late evening when the temperature was a few degrees lower. I wonder if they were delayed because the performance charts stopped at 45C or if it was a payload issue. Incidentally, it was quite tolerable but you wouldn't want to leave your car in the sun, temperatures of 80C were measured in parked cars. It must have been hell in parked aircraft with non white paint jobs.

xdlx wrote:

Most performance charts go to 115F or 45C, so north of that figure all bets are off

All charts go to 125F/51C that I'm aware of. Pratt &GE certify all engines for at least 125F. Boeing and Airbus require it.

DXB has operated at 45C before. Fuel stops...

Lightsaber

RohanDXB wrote:

As per the article which triggered all this - it will reach 45-46 degrees @ 90% humidity. How would the wet bulb temperature develop with that?

It's pretty much impossible that 90% RH would be reached. Again, in hot weather that is something that typically happens only under storm conditions, and temperatures in storm conditions don't usually exceed the high 30s C. The current dewpoint in Dubai is only 26 C, which would imply RH of only 34% at 45 C. (It still feels very humid with a 26 C dewpoint!). But if you did have a day with 45 C and 90% RH, the wet bulb temperature would be 43 C -- immediately threatening to life -- and the heat index, which is supposed to measure perceived temperature, would be above boiling.

There are photos of airplane tires melting into runway asphalt in extreme heat.
The link below shows what happened during a hot day in 2012 at DCA in Washington.

http://i.dailymail.co.uk/i/pix/2012/07/ ... 34x476.jpg

Those runways at DXB are more than 4000m and with no high terrain close to the airport, there shouldn't be any performance issues...

Performance charts so not stop at 45 degrees, they stop at the certified maximum temperature. That's 54 degrees for a 737NG!

When it got that hot in AZ I could always make it seem better by saying it was a dry heat. But just now checking the current conditions at DXB it is 91F with 75% RH at 1:30 in the morning. That just sounds miserable.

Interesting to be a fly on the wall when the EK/RR deal was done, in terms of Power By The Hour (TotalCare) penalties (or absence thereof) for settings based on DXB temperatures.

Perhaps one situation where four engines actually have an edge over two.

EK not the only airline with the issue, but bet they negotiated the best deal.

ikramerica wrote:

ZaphodHarkonnen wrote:

45C is still hugely hot. And from memory is either over or very close to what's considered naturally human habitable. If you're somewhere with working aircon you'll probably be fine. But out on the ramp for hours and hours? People just start breaking at those temps and humidity.

45C isn't the end of the world. We hit 45c three weeks ago at my house. Heat index was about 47c. Felt like an oven but people still did their jobs and there weren't reports of widespread health problems.
You are right that heavy exertion is more dangerous but there are other factors. Being acclimated to such conditions over a lifetime makes negative reactions less likely because your body and brain have learned how to function in that environment.

The problem there is the apparent heat for people. With very high humidity sweat won't evaporate to cool the body. If you are working outside such as ground staff i don't know how you could cope.

desertjets wrote:

But just now checking the current conditions at DXB it is 91F with 75% RH at 1:30 in the morning. That just sounds miserable.

Wow, the humidity really went up overnight. That's a dewpoint of 28 C. So horribly unpleasant.

If the dewpoint stays the same and the daytime temperature reaches 45 C, the wet bulb temperature will be 32 C. That's starting to get close to the danger zone even for well-hydrated people in the shade. For ramp workers dealing with sun and higher temperatures coming from radiation off the ramp, these are really dangerous conditions.

I can't imagine why anyone, unless desperate for a job to survive, would want to spend any time in a place where it is so hot and humid but there is so little actual fresh water around.

I've spent the summer in Marrakech where some days it actually got up to 50 degrees celcius. Life goes on. Flights still take off and land. You just keep out of the sun as much as possible and stay indoors with the aircon on. Walking outside at 50 degrees is dangerous for any long period of time. But everyone has aircon in Dubai so I doubt they'll even notice all that much. It's normal summer weather for them. Everything is built to withstand these temperatures.

Floppie wrote:

Those runways at DXB are more than 4000m and with no high terrain close to the airport, there shouldn't be any performance issues...

I think that despite the long runways, tire speed limitations might end up causing payload penalties. Rotate speeds on a heavy airplane at that density altitude are very high, and depending on payload, etc., sometimes you are limited by tire performance from what I have read. This pops up at airports like BOM that have particularly hot and humid summers. Perhaps someone who is experienced with dispatch or flight ops procedures could weigh in?

ZaphodHarkonnen wrote:

45C is still hugely hot. And from memory is either over or very close to what's considered naturally human habitable. If you're somewhere with working aircon you'll probably be fine. But out on the ramp for hours and hours? People just start breaking at those temps and humidity.

That's funny. I don't consider it warm until it is 40C, 45C is hiking weather.

IMissPiedmont wrote:

ZaphodHarkonnen wrote:

45C is still hugely hot. And from memory is either over or very close to what's considered naturally human habitable. If you're somewhere with working aircon you'll probably be fine. But out on the ramp for hours and hours? People just start breaking at those temps and humidity.

That's funny. I don't consider it warm until it is 40C, 45C is hiking weather.

Strangely enough, I have gone on a few hikes in Riyadh when the temperature was around 40-42 degrees Celsius but at a time close to sunset.
Since the air in Riyadh is probably the driest substance known to man, it was actually completely bearable.

Something that occurred to me is that in Dubai, during the summer all construction & outdoor activity comes to a halt from 12-4 (as per law, strictly enforced was significant financial penalties). I would imagine that closing DXB for such a period is not viable at all. Maybe they work on shorter shifts for just the afternoon?

Ro

FWIW, my advice is "If you can't stand the heat stay out of the desert" But seriously, I'm sure the only consequence will be fuel stops or weight penalties on the longer flights.

Come on guys it was 44C / 111F in Phoenix, AZ today. Not that horribly hot. Mind you we have lower humidity.

Clearly EK needs to lose a shed load of seats on board and install a swimming pool so that passengers can cool down after boarding at DXB