The approach speeds are just so impressive for an aircraft of that size. What an incredible wing. Landing slower than 737s often do.
And that wing meant that we could depart from 24L in LA, whist the 747s and 777s had to go over to 25. Often saved us quite a bit of time. It was a very good wing, which was designed for a future model over 600 tonnes. But, as that model never happened, it really became part of the over engineering of the aircraft.
There are other speeds
GD
S
F
Vref
VRef = VLS
What is the difference?
Are all these speeds basically a method of managing energy within the performance constraints of the aircraft?
Vapp = Vls LDG CONF+ ( 5 ≤ headwind/3 ≤ 15 )
Vls is the lowest selectable speed for the autothrust. It's the speed the aircraft does not want you going any slower than. Autothrust was engaged for 99.9% of all landings.
The aircraft is told which landing configuration we're going to use with the CONF3 / FULL tick box. The wind that is used for the calculation is the one that we enter top left.
Green dot is best lift drag ratio. It was used as the minimum speed. It adjusts with with configuration changes.
In the approach phase, if you want to slow below GD, you'll need to select flaps. F1 to go slower than clean GD, then F2 at S speed, and F3 (or full) at F speed. They're a little different in the takeoff phase. F1 is selected at F and clean at S, but you need to keep the acceleration happening.
In that image, it says trans FL065. Does that mean transition altitude is set to 6,500ft?
Yes. London's TA was 'by ATC'. We'd change the setting as soon as ATC cleared us to an altitude, not a flight level on descent. And of course the reverse on a climb. In this case the FMC wants to know the TA so that it can allow for any vertical deviation caused by the change of pressure scale. There's 9mb between the two settings, so roughly 260'.
The vertical deviation shows that we're almost 2,000' above it's ideal approach path, but that was quite normal, as the system wasn't capable of handling the variations caused by ATC. Nor did it allow for early configuration changes for low speed requirements. The actual height was 5,500, at 16.2 nm to run, and 180 knots. That's near enough to a perfect position.
This was the rest of the displays cropped from the same image.