Robert S 75 Posted December 18, 2009 Share Posted December 18, 2009 OK; with the assumption that jet engines produce more thrust at lower temps, when the pilot enters the outside temp of 54 Celcius into the FMC, the computer would then calculate a lowered thrust of over 25% for the engines to compensate for take off...at full load, may not be enough thrust to adequately take off with the given runway! Link to comment Share on other sites More sharing options...
Just Fly 56 Posted December 18, 2009 Share Posted December 18, 2009 If you take a liter of oxygen (at 20°) and you heat it, its volume will rise. The same law can be applied to fuel: it would take too much place for the same quantity? Link to comment Share on other sites More sharing options...
ChrisB 11 Posted December 18, 2009 Share Posted December 18, 2009 fuel is vaporising and therefore causing vapour locks in the lines. Link to comment Share on other sites More sharing options...
Pi@no 17 Posted December 18, 2009 Share Posted December 18, 2009 The FMC say that ground temperature is incorrect ? Link to comment Share on other sites More sharing options...
ChrisB 11 Posted December 18, 2009 Share Posted December 18, 2009 They can take off, but at those numbers they would probably have to fly empty or with not enough fuel for the trip. Therefore simple economics rule. What's the point in flying if you aren't making money? Link to comment Share on other sites More sharing options...
LCLK 24 Posted December 18, 2009 Share Posted December 18, 2009 They cant take off because the crew is on the beach sipping they frappe Link to comment Share on other sites More sharing options...
SF22 5 Posted December 18, 2009 Share Posted December 18, 2009 Because the asphalt gets softer and heavy aircraft will sink into the asphalt reducing the acceleration? Link to comment Share on other sites More sharing options...
Just Fly 56 Posted December 18, 2009 Share Posted December 18, 2009 They cant take off because the crew is on the beach sipping they frappe Do you go on the beach while it's 54° out? Link to comment Share on other sites More sharing options...
Just Fly 56 Posted December 18, 2009 Share Posted December 18, 2009 Because the company cannot offer whisky (it will evaporate) on board to buisness class passengers Link to comment Share on other sites More sharing options...
Cris B. 120 Posted December 18, 2009 Share Posted December 18, 2009 They cant take off because the crew is on the beach sipping they frappe LOL, Actually, with it being so hot, we would be back at the hotel with the air conditioner running at full blast taking a nap and hopping that the night would bring cooler temps! Other then that I’m going to stay out of it per Mathijs’s request. Link to comment Share on other sites More sharing options...
flyhigh 0 Posted December 18, 2009 Share Posted December 18, 2009 Hi again, maybe the airlines don't have the performance charts for that high of a temperature? Rgds, flyhigh Link to comment Share on other sites More sharing options...
_Dre_ 0 Posted December 18, 2009 Share Posted December 18, 2009 As it's so hot the rubber padding where the airbridges touch the aircraft have begun melting which now leaves "foreign bodies" on the fuselage. So after being forced to remove the airbridges there is no boarding; no boarding = no flight. Link to comment Share on other sites More sharing options...
Habit 0 Posted December 18, 2009 Share Posted December 18, 2009 Is it because of an engine nacelle overheat warning. I remember being a pax on a C130 in very high tempratures in Dubai. We couldn't start because of this. Link to comment Share on other sites More sharing options...
Thralni 24 Posted December 18, 2009 Share Posted December 18, 2009 54 degrees... That's a temperature people can't survive, if I remember correctly. Of course you can't take off with such temperatures! The pilots will not be able to function normally, or they would have to use air conditioning, but the system would have to perform so much cooling that it'll require FAR too much fuel. That will make the cost of trip far too expensive to have a good price, so either they charge the passengers more (which is a grand "no") or the loose bigtime on the flight (which is also a "no"). It's my guess that airlines will not let their aircraft takeoff, simply because it's no good operating temperature for the pilots themselves. You can't possibly demand people to perform intensive work at that temperature, and even with air conditioning, as I said, you'd be burning too much fuel to make the flight affordable (let alone the detrimental effects on the distance you can fly!). I just looked it up to be sure: it seems people can not survive temperatures above 45 degrees for too long. The body just can't take it. Muscles will become rigid at between 45-50 degrees, and eventually, at 54 degrees, the entire body will be rigid. Because of that, you can't breath, and you'll suffocate. So, as you can see, at 54 degrees, the pilots die. And again, even when using air conditioning, you'd burn gallons of fuel: the cost of the trip would far outweigh the profit! This basically means that any company that isn't huge and doesn't have great profits anyway, will not be able to operate: meaning just about all airlines will have to keep their planes on the ground. I realized I just said the same thing three times... Oh well. Link to comment Share on other sites More sharing options...
SF22 5 Posted December 18, 2009 Share Posted December 18, 2009 A bit simlar as Habit's post but maybe something with single engine procedures? If one of two engines fail the temperature of the remaining engine will rise so high that the engine gets overheated and the pilot has to retard the thrust resulting in that the engine won't produce enough thrust? Link to comment Share on other sites More sharing options...
bionicCrab 7 Posted December 18, 2009 Share Posted December 18, 2009 Actually wait.. according the 747 performance table for landing there is nothing given for above 50 degrees... therefore if the plane can't land in case of emergency, it can't take off either. Link to comment Share on other sites More sharing options...
Albrecht 9 Posted December 18, 2009 Share Posted December 18, 2009 Ground staff does not work. Link to comment Share on other sites More sharing options...
LGW 2 Posted December 18, 2009 Share Posted December 18, 2009 Viewing A330 performance out of DXB wjere conditions could happen..the only reason i could suggest is that full thrust take-off is required, as temp is higher than Tref.. so i would guess the ones that can't take off are too heavy, which at DXB would be A330 that weight more than 200 tonnes steve Link to comment Share on other sites More sharing options...
flusi4ever 39 Posted December 18, 2009 Share Posted December 18, 2009 The aircraft thinks, there is a fire and shuts the engines down. Link to comment Share on other sites More sharing options...
Bombayduck 7 Posted December 18, 2009 Share Posted December 18, 2009 Because of the high air temperature, the power of your engines will be less because your engines are temperature limited. Link to comment Share on other sites More sharing options...
Goulash 11 Posted December 18, 2009 Share Posted December 18, 2009 My 2 bob. Is it because if you enter the max temperature into the FMC at 54/55C you can only get the maximum thrust reduction of 25%, meaning there wouldn't be enough power to take off as a jet engine produces more thrust in cooler temperatures. In other words you simply don't have enough power to take off, specially fully loaded. Or not lol Link to comment Share on other sites More sharing options...
Rónán O Cadhain 71 Posted December 18, 2009 Share Posted December 18, 2009 The added heat means the engines aren't able to run high because they will overheat quicker. Preformance charts don't go up that high. FMC won't recognise temperature. Aircraft aren't certified to fly in temps of 54 degrees plus, due to the raerity of the temp why would the manufacturer go to the trouble of certifying it at unresonable tepms? Link to comment Share on other sites More sharing options...
Rónán O Cadhain 71 Posted December 18, 2009 Share Posted December 18, 2009 (ignore) Link to comment Share on other sites More sharing options...
Paul G 13 Posted December 18, 2009 Share Posted December 18, 2009 After doing some testing I've found that at 54C the time and distance to V1 in a 47-4 is about 8,000 feet, time to Rotation is around 10,000 feet and the time to V2: 3 Miles, the climb speed is also reduced substantially too. After testing with the Default 172 I've found some quite interesting things: At the Lowest Air Temp that FSX will alow (Same for the Dew Point) the take off speed was reached quite fast and when the Temps got set to the highest FSX would alow (Again Dew Points Flipped too) the engine actually quit on me at those temps and had to restarted, the rotation speed took much longer to reach (It was hot enough that I had to lean the Mix at Sea Level) Link to comment Share on other sites More sharing options...
Rónán O Cadhain 71 Posted December 18, 2009 Share Posted December 18, 2009 Airliners aren't certifited for temperatures of 54 degrees plus. Link to comment Share on other sites More sharing options...
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