expedite_climb -
Several years ago I saw a table giving depression of the natural horizon with altitude - ie the higher you go, the more "down" you have to look to see the intersection of sea & sky. So at FL300 the natural horizon is a poor reference to use when trying to determine whether something is above or below your altitude. Is this what your question refers to?
But in the context of the original post, I suppose the HUD will give the pilot an actual (tangential to surface of earth) horizon mark. So you could say "Well that cloud is 2.5° below the actual horizon (or 0° pitch reference) and is 300nm away so we will just clear it" or words to that effect.
Disclaimer - never used a HUD, don't have the table of horizon depression against altitude with me. So this is all just speculation eh? But I do think that 2.5° at 300nm is correct...
galaxy-flyer -
Sun moves at 15° per hour east to west. 1° = 60nm times cosine latitude.
Thus, at 60° latitude, 15°/hr = 15 x 60 x cos(60) = 450 knots.
You could beat the sun by
walking around the earth if you pick the right place...
regards,
O8
