Originally Posted by
Red Four
So how long are the existing RESA's at SOU? An arrestor bed would seem to indicate an area of CAA concern. Edit to add, I have just seen, 90m each end.
SOU has a Code 3 runway (iaw CAP 168/ICAO Annex 14). As such it is required to provide a minimum RESA length of 90 metres. This is in addition to the runway strip end which extends for 60 metres beyond the end of the TORA. Consequently a
minimum of 150 metres overrun must be provided.
The recommended RESA length is 240 metres. If an aerodrome cannot provide this length a risk assessment must show that any risks of non containment of an overrun are at a sufficently low level as to become tolerable. Mitigation included in the assessment may include runway friction characteristics, which can normally be improved by grooving of the runway surface to assist with drainage in wet conditions.
Any increase in 02 TORA/LDA may be minimal, this is of course is due to the need to provide a RESA beyond the declared TORA.
Assuming that SOU owns the land out to the second 20 approach lighting crossbar (if they don't now is possibly the time to dust off the cheque book and go speak to the railyard owner) there is about 230 metres available, giving a possible RESA length of 170 metres with the current runway, less whatever a blast screen is going to take up. Just how much of this can be clawed back by a risk assessment to add to the current 02 TORA/LDA?
Looking at 20 TORA, which is currently 1650 metres (less than the 1723 metre runway length due to RESA requirement at the south end), with an addition of 164 metres on the north end there will be a total possible TORA of 1814 metres. However as the runway width does not meet Code 4 runway criteria, the maximum declared TORA of 1799 metres for a Code 3 runway will apply. This then extends the current RWY 20 90 metre RESA by another 15 metres. RWY 20 LDA cannot be increased as there remains a need for the current 20 displaced threshold.
Final runway TORAs/LDAs after the extension will accordingly rest on how robust a risk assessment SOU can produce to demonstrate a tolerable level of safety with less than the recommended 240 metre RESAs.