Obstacle Limitation Surface Designation
Wellington Airport has had an Airspace Obstacle Limitation Surface (OLS) Designation in the Wellington City Council Operative District Plan since 1999. This has been rolled over into the Council’s new 2024 District Plan.
Link: 2024 District Plan: Appeals Version - WIAL1 OLS Designation
While this updated designation means more people are likely to need approval for developments that breach the OLS, it will remain rare and unlikely for any request to be declined unless in the very unlikely case that aircraft safety would be compromised.
It is quick, easy and free for any proposal to be checked. Wellington Airport endeavours to answer most queries within a day or two and we have created an easy online tool (accessed through the WCC District Plan maps) for people to check whether they need approval. Refer to “How do I find out of my proposal penetrates the OLS?” below for step-by-step instructions.
What is an Obstacle Limitation Surface (OLS):
New Zealand’s Civil Aviation (CAA) rules require airports to provide Obstacle Limitation Surfaces (OLS) around an airport.
OLS are defined conceptual three-dimensional surfaces that radiate outwards from an airport runway in the vicinity of the airport as depicted shown in Figure 1 below. Each Surface serves a particular purpose in managing obstacle clearance and airspace protection.
Figure 1: A three-dimensional depiction of the obstacle limitation surfaces surrounding an airport.
The purpose of OLS is to define areas of airspace that should be free of obstacles to enable aircraft to maintain a satisfactory level of safety while manoeuvring at low altitude in the vicinity of the airport and to protect against collision. Their provision assists not just to provide an area for aircraft to safely approach and depart the airport under normal circumstances, but importantly also when the flight performance of the aircraft is impaired, such as when an engine is inoperative.
In Wellington given the OLS extends well beyond land controlled by the Airport itself, the only way the Airport can provide for OLS is via height restriction controls included as part of a designation in the District Plan.
In an ideal world, the airspace defined by OLS would be totally free of obstacles and subject to controls to prevent objects such as buildings, structures and trees from penetrating them.
However, given the hilly terrain of Wellington where much of the terrain already penetrates the OLS, such an approach would significantly impact on development rights in those locations.
Figure 2 below shows a 2-dimensional version of the Wellington Airport OLS. As can be seen, the OLS extend some distance beyond the Airport’s actual location. The areas where the existing terrain penetrates the OLS are generally shown with a blue outline.
Figure 2: Wellington International Airport Obstacle Limitation Surfaces
The OLS Designation recognises this potential impact through conditions of the Designation which allow for a degree of penetration to reduce the loss of development rights that would otherwise result from a strict adherence to the CAA OLS requirements. The degree of allowable penetration depends on the particular OLS involved and is outlined below.
What type of objects are the Airport concerned about?
Permanent and temporary objects (or activities) can result in the OLS being penetrated and therefore have the potential to adversely impact on the safety and efficiency of flight operations at the Airport.
This includes structures and buildings, and the equipment used to construct them – such as cranes, house wraps/scaffolding. Trees can also be problematic if they grow into the OLS.
My property is within the Airports OLS Airport Designation – What does this mean?
As can be seen in Figure 2 above, most properties within the Wellington District have the WIAL OLS Designation in the airspace over them.
However what matters is whether a proposed building/structure (including any extension) or other object will penetrate the OLS, and if so, the extent of that penetration and whether it will affect aircraft safety.
The OLS Designation restrictions do not apply to a proposed building/structure or other object that is located within the airspace above each property but beneath the OLS.
How do I find out if my proposal penetrates the OLS?
To find out whether your proposed building/structure or other object will penetrate the OLS, you can check on Wellington City Councils interactive District Planning Map (Wellington City 2024 District Plan: Appeals Version) using the Property Search function.
Start by searching your property address which will bring up a Planning Map highlighting your property on the map.
On the information panel to the left of the map go to the “Designations” tab.
This will indicate the OLS surface which is relevant to your property and how many metres above ground level can be built before penetrating the Airport’s OLS.
On the “Map Layers” panel to the right of the map, first remove the “Specific Controls” ticked box, and go to the “Designations” tab and click on the box for “WIAL – Obstacle Limitation Surface (OLS)” (the second to last on the list).
This will identify the height differential between the ground level of your property and the OLS which is indicated by different colours on the Planning Map and will indicate any variation in that height differential across the property.
This in turn will provide an indication as to how the OLS may affect each part of the entire property so it is possible to assess whether the area within the property that is proposed to be built on will likely penetrate the OLS, or not.
Note: To identify which colour delineates the applicable height differential, use the “Legend” tab and go to “OLS and Ground Height Difference”.
My proposal will penetrate the Airport’s OLS – What do I do?
Once you have found out that your proposal will penetrate the OLS, you will need to notify the Airport and written consent may be required from the Airport depending on your location and the level of penetration.
The Table below sets out the circumstances in which a proposal will require the Airport’s written consent:
| OLS Surface | Notification to Wellington Airport | When written consent from Wellington Airport is required* |
|---|---|---|
Transitional Side Slope |
Any building/structure (including any extension) or other object that penetrates the OLS and is 8 metres or less in height above ground level. This excludes specified properties in Bridge Street, Cairns Street, Jean Batten Street and Coutts Street in Rongotai (please contact us for details) |
Any building/structure (including any extension) or other object that penetrates the OLS and exceeds 8 metres above ground level. This excludes specified properties in Bridge Street, Cairns Street, Jean Batten Street and Coutts Street in Rongotai (please contact us for details) |
Transitional Side Slope |
For specified properties in Bridge Street, Cairns Street, Jean Batten Street and Coutts Street in Rongotai identified in Figure 1 of WIAL1 OLS Designation, any building/structure (including any extension) or other object less than the specified height limits. |
For specified properties in Bridge Street, Cairns Street, Jean Batten Street and Coutts Street in Rongotai identified in Figure 1 of WIAL1 OLS Designation, any building/structure (including any extension) or other object that exceeds the specified height limits. |
Inner Horizontal, Conical, Take-off and Approach Surfaces |
Any building/structure or other object that penetrates the OLS and is 8 metres or less in height above ground level. |
Any building/structure or other object that penetrates the OLS and is more than 8 metres above ground level. |
Outer Horizontal Surface |
Any building/structure or other object that penetrates the OLS and is 30 metres or less in height above ground level. |
Any building/structure or other object that penetrates the OLS and is more than 30 metres above ground level. |
To find out if written consent is required from the Airport, please fill out the enquiry form below or you can send us any proposed development plans via email: WIAL1_OLS@wellingtonairport.co.nz.
Please ensure you include information relating to the height of any new structure or buildings above ground level and the highest point of the structure or building above Mean Sea Level (MSL) (NZ Vertical Datum 2016).
Airport Consideration Process
Once Airport staff have received your enquiry (and any plans) they will consider whether written consent is required from the Airport and if so whether the proposal will affect aircraft safety. This will be assessed on a case-by-case basis.
The Airport will let you know within 1-2 working days if they require any further information from you to assist their assessment (or if written consent is not required). This information assists the Airport in its statutory duties as an airport operator in identifying and recording obstacles.
Where written consent is required for your proposal, various aviation related factors will be considered such as whether there is higher terrain or other existing buildings or permanent structures in the vicinity that effectively shields the proposal from having any adverse effects on aircraft safety.
There is no fee for this assessment by the Airport.
In some rare and more complex cases and in particular locations the Airport may require additional technical aviation information to assess the effect of a proposal. In these circumstances you might be required to obtain an Aeronautical Study from Aeropath (a subsidiary of Airways NZ) who will assess whether the proposal will have any detrimental effects on aircraft flight procedures in and out of Wellington Airport.
After considering your proposal and all relevant information, the Airport will determine whether or not it is prepared to provide written consent for the proposal.
It is important to note that if the Airport does not provide its written consent where it is required, the proposal cannot go ahead as to do so would breach section 176 of the RMA.
For any enquiries relating to the OLS, please complete our enquiry form.
Alternatively, email us with any relevant information to WIAL1_OLS@wellingtonairport.co.nz.