Originally Posted by BOAC
Where did the 120kts, 'the bunt for the final approach' and 5.9D come from?
From the link Retired put up.
Re bunt, while the document goes into incredibly detailed lengths to calculate, to the nearest foot/min, the required descent rate, it abjectly fails to address how you compensate for the fact that the final descent will probably be started from level flight. The action lowering the nose to commence the descent (bunt) will put you at least 100ft high straight off, with no idea how high you subsequently are until you either clip a step or find yourself with 4 whites at the DDA.
Re your quip about FMC failure, it should be plainly obvious to an ace like you that the distance/altitude profile technique does not require any such wizardy. You just push a bit, pull a bit using your VSI to stay on the required profile.