ICAO RESA lengths are 90 m. minimum and 300 m. recommended. The certifying agency for St. Helena ASSI has apparently applied the 300 m. length to both ends of St. Helena's runway. Since the approach end of 20 has no under-run, the entire 300 m. is subtracted from the paved length. There is about a 200 m. under-run at the approach end of 02 so only 100 m. was subtracted from the pavement there. The originally contracted carrier Comair apparently applied to ASSI to reduce the RESAs to 90 m. and that request was recently denied as "inappropriate". That's how the 1950 m. runway length became 1535 m. for landing on 02. ( A 5 meter discrepancy floats around somewhere in the math that I don't understand. )
Last edited by lolder; 28th Feb 2017 at 13:00.