Qantas744er wrote:DylanHarvey wrote:jayunited wrote:
You start to see performance penalties when the temperature hits 95F/97F or 35C/36C, at those temps you are holding off at least 3,000 LBS of cargo if not more.
Then there are days when UA has had to jettison all the cargo out of SYD but only when the temperature exceeds 105F or 107F / 40C or 41.6C. If we are looking at a full pax cabin and you are talking temperatures in this range or higher in most cases you can forget about taking the cargo out of SYD or MEL in some cases the non revs have to be pulled off the aircraft. There are days during the southern hemispheres summer where even though the dispatcher has padded the temperature, 2-4 degrees in the release it isn't enough. Sydney at 10:00 is already pushing 101F/102F and the captain 20 minutes before departure will have the dispatcher rerun the flight plan with a temp of 105F because the captain knows they are going to sit on the ground after push back waiting for the runway for another 20-30 minutes, and it blows everything out of the water.
The 789 is a very capable aircraft, and it does have its limits, but it still performs a hell of a lot better than the 77E.
Valuable information as always. And yes the 77E was a pioneer in it’s time, but the time is now for the Dreamliner and the Airbus. How much of a difference would it make if UA had taken The higher thrust GENx? They have 72 or 73k on the 89 now right?
UA B789 have GEnx-1B74/75 ( 76,700Lbs )
UA B788 have GEnx-1B70 ( 72,300Lbs )
The highest GEnx rating available on the B789 is the -1B76A (78,500Lbs). The additional thrust would certainly help the B789 out of FAOR/JNB.
They have the GENx-1b78/p2. I wonder if they have been certified on anything yet. I thought I read that was certified last year. 80,400lbs.