Groundspeed upslope : nothing.
Groundspeed * upslope is going to be your vertical speed while traveling at a given GS on a runway that has an upslope.
From an engineering point of view, a flare is going to be an increase in lift that is going to create in increase in load factor (vertical acceleration). This load factor (typically 1.05 to 1.15g) will change the vertical speed according to the physics formulae.
If you have a runway upslope (that's also mentioned in the FCTM) you will have to make a larger change in vertical speed and hence will require a longer flare (or more pronounced)
I'm not advocating to use RA for landing profile, of course not. However I've noted several pilots writing that they waited for this or that RA callout to start their flare.
As 172 driver pointed, flare is a complex thing and the pilot's and the engineer's point of view are very different : one is sitting at his desk looking at curves, taking one hour to analyze ten seconds. The other one is in a moving machine in real time.. Plus the flare will induce vertical accelerations in the flight deck that are absent at the airplane CG (due to the flight deck being so much forward of CG)
So when the engineer is tired of analyzing he will just say "flaring is (basic) airmanship, and hence does not need to be taught by the manufacturer"
As for you question ..
I'm guessing its a trick question since an airplane is supposed to be at 50ft over the runway threshold.
However, in an autoland (I'm choosing this because they should be more similar to each other than manual landings) the aircraft will descend on the glide slope. So basically the ILS antenna will follow the glide slope down to a certain altitude, then the aircraft will freeze its flight path angle down to flaring. Flare should occur below 50ft in normal conditions.
Since the gear is lower than the glide antenna and since the radio altimeter measures height from the ground under the tail up to the gear position (while correcting for pitch angle, but only for certain things like RA display on the PFD), you should get the 50ft RA callout
before. A few tens of meters before.
That's if and only if my assumptions about the different sensors, etc.. are correct.
For instance, they may have introduced a correction so that the CG and not the antenna follow the glide path.
But we're starting to go into details that would require several tens of minutes to check them for certain.
If we're talking about a visual approach following the PAPI.. that's another story
If there is a ground slope near the threshold, this will change things as well
P.S. Without claiming it particularly high or low, I'm happy with the number of naked women (both real and websites) I've seen
Originally Posted by
172_driver
I hope KayPam et al. can appreciate the occasional sarcastic jokes in this thread instead rather than taking it personally
Yes, this forum is good fun (see the line just above your quote)