1) How are runways numbered? Why are they not consecutive? I heard that runway numbers are approximate magnetic headings, but I find that strange because for example, at CLE, one runway is 24L, and the opposite end is 6R; those do not look like opposite magnetic headings.
Runway numbers are determined from approach direction using magnetic azimuth of the centerline of the runway as reference. L and R are used for two parallel runways and L, C and R for 3 parallel runways. However, in order to avoid confusion on some airports with several parallel runways a new runway designator is normally used. For example, Frankfurt has two parallel runways 25R and 25L and their respective opposite thresholds. But runway 25L has a second landing threshold (1500m from original landing edge 25L) designated as 26L (it’s used only for landing of aircrafts with a maximum landing weight less than 136,000kg and under some meteorological conditions and traffic demand). LAX has 4 parallel runways with the same magnetic azimuth. But they’re designated as 25L/07R, 25R/07L for the south complex, and 24L/06R, 24R/06L for the north complex.
2) I know that the "piano keys" at the ends of runways tell you the width of the runway. But, how do you determine this? I think (not sure) that each stripe is 10 feet (I am probably wrong at this).
From AIM:
Runway Width X Number of Stripes
60ft - 4
75ft - 6
100ft - 8
150ft - 12
200ft - 16
Bkmk
