T1 = temporary runway in the OPT
Amazing. The provider of this EFB probably had a committee deciding what codings to use for what situation. How does anyone come up with T1 = temporary? What has '1' got to do with it, or was this 'phase 1' of runway maintenance? Isn't "Temp" a better coding?
The aircraft travelled along taxiway S, running parallel to the runway, before being cleared to line up at the intersection.
This clearance was acknowledged by the 777’s crew,
This would suggest the crew requested T1. It would not be for ATC to offer it. I wonder if anyone in ATC thought, "that's odd, they've never done that before." It's not for ATC to 2nd guess the crew. It would have been unusual for ATC to ask, "are you sure about T1." but it might have closed the holes, except the crew might have said, "yes."
Back to a discussion there was a while ago about an AF trying to rotate a heavy a/c many kts too slow. Naturally it was the wrong weight in the EFB. The discussion brought up the point about having a 'feel' and 'mental gross error check' for performance calculations & takeoff speeds. Surely the same could be said for this case about TORA/TODA. I assume the crew knew the TODA from T1. With a little thought about past operations I would have expected there to be a "seems a little short to me. What do you think?" moment, before punching numbers into a computer and accepting the results willy nilly.
Sadly that is what the modern human has become. In all my cadet teachings, as an old fart, I gave examples of various gross error checks and mental estimates for different scenarios, both on grounded in the air, aligned with stories about the consequences of those who didn't make them. I don't think too many airlines, even on command courses, educate their crews in this time aged technique. It is disappointing, in cadet training, to see load sheet figures added up with a calculator. What ever happened to brain power? Even worse considering that cadet pilots are usually required to have a maths/science orientated education.
It was still quite common to see low hour F/O's blindly follow VNAV PTH and not consider Distance v Height. Often VNAV was rubbish and they then asked why it was adding thrust and suddenly changed to 'below path' or dived, accelerated now being 'above path'. The answer had been staring at them for a few minutes, if they had cared to observe.
I have some nervousness that EFB's, though great in paper saving and perhaps allowing higher TOW's, might also lead to more erroneous takeoffs. The gross error checks is perhaps one defence. Having both pilots use their own EFB's to cross check the performance result doesn't help if the basic data that is entered is duff gen. Rubbish into both EFB = same rubbish out of both.