Kingscote Airport Business Case Appendices - Kangaroo Island ...

5.2.5 Practical Limitation on Runway LengthRunway length available if maximising use of existing runway stripThe maximum length of runway that could be constructed within the existing runway strip oflength 1693m whilst allowing for a 60m minimum required clearway at each end is 1573m. Thisis sufficient for Scenario 2 only.Runway Length Available Within Existing Aerodrome BoundaryExtension of the runway strip to the north is constrained by Arranmore Road being locatedapproximately 102m north of the existing clearway end. Allowing for a future 2.1m high securityfence on the road reserve road boundary would result in a future obstacle gradient of 2.1% fromthe current end of clearway. The desirable maximum gradient is 2%In addition any further extension to the north will run into obstacle clearance issues, in particulartall Eucalypt trees growing along the Cygnet River. Approval to remove or trim these trees islikely to be difficult to obtain.At the southern end, the existing boundary is approximately 328m south of the southern end ofrunway strip of Runway 01. (Note that a drain is located 158m south of the existing runway, andthat a new pipe will be required beneath any runway extension across it). Allowing 100mclearance from a future security fence, the maximum extension would be 228m (that is equal to328m - 100m).Accordingly, the maximum available runway length within the existing aerodrome boundarywould be 1801m (= 1573m derived above + 228m). This is insufficient for both Scenarios 3 and4.Maximum Runway Length Assuming Property AcquisitionA further extension would be limited to the south only, assuming that Arranmore Road wouldneed to remain in place. Significant trees along the Cygnet River are also likely to prove to be aconstraint to development in that direction.An extension to the south is potentially limited by: Low area and dwellings 1740m from the existing runway end Noise on residences and bowling club Obstacle clearance issues due to many large trees.The noise issue is discussed in more detail in Section 5.3 below.Survey data shows a range of large trees in the vicinity of the above houses. These extend inheight to 24.73m above the existing clearway. Extending the runway 600m to the south to a totallength of 2000m would increases the gradient over the trees to 2.19%.Extending the runway to 2500m total length greatly increases the amount of clearing that wouldneed to be undertaken to provide an appropriate approach gradient. The likely problems insecuring the necessary approvals for clearing large numbers of trees tends to suggest thepractical runway limit is of the order of 2000m, and that Scenario 4 is unlikely to be a viableoption.5.3 Noise Associated with Code 4 AircraftThere are a number of dwellings located 3150m - 3300 from the start of takeoff Runway 19.AS 2021 Acoustics—Aircraft Noise Intrusion—Building Siting and Construction shows a potentialnoise level at the dwellings of 88 dB(A) for B737 / A320 taking off to the south from a 2500m longrunway.Ref No. 20120935DR1A Kingscote Airport Infrastructure Study Report 10