Originally Posted by
Red Four
Thanks yes I realised that. Do you know what the new RESA lengths will be under this extension plan?
The subject of how long RESAs will be with an extended runway is somewhat akin to how long is a piece of string?
As mentioned the minimum length of a RESA should be 90 metres, they should also have a width of twice the runway width. Currently 02/20 meets this minimum requirement with TORA 1723 (02) and 1650 (20). The current UK AIP entries for SOU specify a 90 metre RESA for both runways.
One further point to remember is that a RESA is an
additional requirement to a runway strip, which surrounds the runway with the intent that it should be obstacle free, albeit frangible signs/other equipment may be present if there for air navigational purposes.
Consequently the absolute minimum undershoot/overshoot protected area needs to be 150 metres (strip end + RESA).
The conundrum is by extending the runway by 164 metres can/has the airport owner convinced the CAA that an acceptable safety margin exists with current RESAs? If not then what could be gained by extending the runway paved surface is going to be eroded by a need to provide a longer RESA.
The most potential gain with the extension is runway 20. If the CAA will agree to the current south end RESA the potential TORA will be 1799 metres (current 1650 metre TORA plus 149 metres). Why only 149 metre increase? As the runway is classified as Code 3 (due to its width) the maximum TORA for a Code 3 is 1799 metres. The remaining 15 metres can be added to the current RESA.
Runway 02 could
possibly have the TORA increased. Looking at Google Earth the proposed extension will require re-alignment of the current boundary fence in order to accommodate it. Assuming that there is only 164 metres to play with, subtracting the minimum 150 metres (strip end + 90 metres) that gives a potential TORA 1737 metres. If any of the land outside of the current boundary fence, as it appears that it is, anything that can be reclaimed by levelling it will be a bonus and possibly permit further extension of the 02 TORA towards the maximum 1799 metres.
As with many things at SOU, nothing is simple. Any extension of the 02 TORA will take the end of it closer to the large rail sheds, possibly negating any extra gained due to increasing obstacles in the take-off climb surface.
I sincerely hope that AGS has done all their homework, including speaking to prospective operators or aircraft manufacturers, and has already secured agreement from CAA as to the RESA lengths and thereby the TORA increases that will be possible.