400kts wrote on Jul 24
th, 2020 at 4:21pm:
Ok tried again some more takeoff, looks like the only way to get off the ground with a good thrust is with a TO or D-TO setting with a max 30° assumed temp, almost I can fly this baby, I will forget about D-TO 1 or 2 till the next update that I hope will solve the issue wherever it could be.
For what concern D-TO or not is all about the company policy as far as I know, in Europe I know 1 is used by some operators, on the 777 as well.
I got some interesting data for you:
First, are you using any type of performance calculator?
Because according to mine: the ONLY way to be able to use a TO2 takeoff for example on a perfect weather day, (ISA and 0/0 wind) on an 11,350ft runway with no obstables is if your takeoff weight is under 330,050lb. Which means on a fully (pax) loaded semi-low density 767 (take Delta Air Lines' 30/184 config), and in my case 21k lb of cargo, the max fuel would be as low as 80,000lb. Higher density planes would be nearly impossible even with less fuel.
As far as actual data I got from the CS767, on my perfomance calculator I put in for a forced TO2 takeoff, it made me remove about 50k of fuel! So I did that and brought my weight down to 317,500lb and took-off. It estimated I'd have about 2400ft of stop margin at V1. Looking at the video and measuring on google earth, I had about 2900ft. You can also see the climb, it had no issue with that either! (I was also only at flaps 5).
In conclusion, I'd say their thrust model on the 767 (unlike the 757) is pretty good! It seems simmers are either derating when they shouldn't be, or using way too high assumed temperatures. I was actually surprised to see the results and how close they were to an actual performance calculator. For reference, I also used the exact same engine type on my calculator (PW4060), to ensure a fair test.
https://www.youtube.com/watch?v=FkubBzG9SKA&feature=youtu.be