Preparing an airstrip
Flying into an unfamiliar airstrip brings with it lots of unknowns. It is vital that our pilots are assured runways are clear of animals, washouts and soft surfaces to protect the safety of the crew, patients and aircraft when arriving at these airstrips, in rural and remote areas, particularly at night.
Although difficult to achieve, good site selection including soil composition and drainage, is most important as boggy strips prevent more landings than any other factor.
Some pointers to natural surface airstrip site selection are:
- look for areas that are naturally well drained and not subject to flooding or water ponding.
- look for areas without frequent surface undulations. Ideally there should be a gentle fall along the length of the airstrip and a very slight camber on the runway. Pronounced one way slopes across the runway should be avoided as they can cause surface scouring.
- Give preference to sites having soil types that, from local experience, remain smooth and compact when trafficked.
- very sandy soils;
- rocky terrain;
- soils that become boggy or slippery when wet
Make sure that the selected site:
- can comfortably accommodate required airstrip dimensions and physical characteristics and is aligned into the stronger prevailing surface winds;
- avoids penetration of the approach and take off surfaces and the lateral transitional surfaces (where required) by immovable objects;
- remains accessible to normal surface transport at all times when the airstrip in useable.
Endeavour to select a site where:
- no hills (or terrain) or man-made objects (masts, buildings, etc.) more than 45 metres above airstrip elevation exist within 2500 metres (ideally 4000 metres) of the site;
- aeroplanes will not fly close to or over residential or built up areas, particularly during normal landing and take-off phases of flight;
- future use of the airstrip is not likely to be compromised by the growth of obstacles around it.
Graphic: minimum requirements
Due to the slightly differing operating and licensing conditions applicable to each division of the RFDS, there are slightly different minimum airstrip requirements. The general requirements are based on national Guidelines for Aeroplane Landing Areas.
PLEASE NOTE - the Minimum Airstrip Requirements may differ slightly for the RFDS Section applicable to your particular location. You are strongly encouraged to contact your respective RFDS office directly to discuss your airstrip with their aviation staff.
The key requirements are summarised below. Before constructing a rural airstrip, make sure to contact the RFDS in your state location to get copies of detailed planning documents appropriate for your area/region.
The preferred runway size for RFDS aircraft to be able to land and take-off is 1200 metres in length. We are able to operate out of shorter runways but we may be operationally restricted as a consequence eg. reduced fuel load restricting range. The runway direction should be aligned with the prevailing wind direction.
To facilitate our aircraft landing both day and night, the width must be a minimum of 90 metres and should be clear of trees, stumps, saplings, ant hills or any other obstacles. If only day operations are anticipated, the width can be reduced to 45 metres but this is not recommended unless there is a night-capable airstrip nearby that can be used in a medical emergency.
The centre 18 metres (20 metres is preferred) which is used by the aircraft under normal operations must be a firm smooth surface which a heavily sprung vehicle can be driven over at a speed no less than 80 kph without undue discomfort to the occupant - this will not impede the take off or landing of aircraft.
From the edge of the runway, the area each side out to 22.5 metres from the runway centre-line needs to be cleared to ensure minimal damage to an aeroplane if it were to run off the runway during take off or landing.
The remaining area outside 22.5 metres of each side may be flown over by an aircraft in the event of a missed approach or go-around. It should therefore be free of tree stumps, large rocks or stones, fencing, wire and any other obstacles above ground but may include ditches or drains below ground level.
The areas at the ends of the runway which are over-flown by aircraft on approach and take-off must be clear of any obstructions such as trees, fences or power lines that would otherwise reduce the effective operational length of the runway and pose a safety hazard.
Ideally it should be possible to park the aircraft off the runway to avoid interrupting other operations and possible safety concerns. A parking apron should be constructed in a location which is both convenient to the runway and also readily accessible by ground transport, and at a distance from the runway such that aircraft and vehicles do not pose a hazard to any other aircraft using the runway.
A windsock is needed to indicate the wind strength and direction to our pilots when they are approaching the airstrip and this ideally is located adjacent to the parking apron.
The runway strip, apron and any taxiways needs to be marked so that all are clearly visible to pilots, particularly when they are coming into land.
Lighting of the runway, taxiway, windsock and parking apron is also required for night operations.
Graphic: Rural Airstrip fencing
Livestock and wild animals are extremely dangerous to aircraft, especially at night where it is difficult for the pilot to see them. They cause considerable damage to the strip surface particularly during heavy rain where their hoofs leave large indents and ruts. It is preferable that your strip is completely fenced to prevent livestock from wandering onto the surface during landing or take off. If the airstrip is not fenced, clearing of the strip and surrounding area is essential.
Care & Maintenance
Your failure to do this could result in a tragedy.
There are in excess of 2,000 landing strips in the RFDS network, many of which are used on a regular basis and many others that exist purely for medical visits.
RFDS pilots are continually checked for their proficiency in operating within all kinds of airfields, both day and night, in good and bad weather and as such, are highly regarded for their abilities within the aviation industry.
Our pilots always put safety first and have a CAN DO, BUT CAN DO SAFELY mindset, which means they will NEVER jeopardise the safety of the aircraft and crew by flying into unknown or poorly maintained airfields.
Therefore, it is important that your airstrip is kept well maintained on a regular basis, especially after heavy rain periods. Please do not wait for a medical emergency to occur before you maintain your airstrip.
RFDS aircraft have tricycle undercarriages and touch down speeds at nearly 200 kph which calls for a much smoother landing surface than that required for other aircraft, to effectively maintain full steerage control and avoid any possibility of aircraft damage.
Our pilots are happy to advise you on airstrip standards and we look forward to your full co-operation in this regard. As a guide the following information should assist you in identifying how you can maintain your airstrip so that the RFDS can always attend in an emergency situation.
The distance required for landing and take off varies considerably with the strip surface type, wind, temperature, elevation above sea level and the weight of the aircraft at the time.
For reliable service, strips should be at least 1,000 metres long adding an additional 90 metres for every 1,000 feet above sea-level. Whilst landing on shorter strips is possible, it cannot be guaranteed at all times.
As mentioned above, the surface of the strip affects the length required for take off and landing. The best surface is sealed bitumen and the worst surface long wet grass. Sealing a strip with bitumen is expensive and unless your airstrip is used for regular community access, we would not expect you to go to that expense.
You can help us by following the below guidelines:
Grass surfaces should have the strip width slashed on a regular basis and cleared of any saplings, fallen logs or ant and termite mounds. Remember to trim around strip edge cone markers or white painted tyres used as strip markers so they are clearly visible to the pilot.
Gravel/clay surfaces should be clear of ruts, undulations, large rocks, ant and termite mounds and where possible regularly graded to remove livestock hoof prints and tyre ruts, especially after heavy rain.
The immediate 15 metres either side of the strip surface should be cleared of any obstacles including ant hills, tree stumps, large rocks or stones and fencing wire, to ensure minimal damage to the aircraft should it run off the strip during landing or take off.
The presence of holes, cracks and ruts will degrade the aircraft's performance and handling and will increase the possibility of structural damage. The smoothness of the surface can be tested by driving a fully laden 3 tonne vehicle along the runway at a speed of 80kph. If this is accomplished without discomfort to the occupants, the surface can be considered satisfactory.
Approach and take off areas
At either end of the landing site, the approach and take off areas should include of an area of 900 metres which is clear of objects including fences, trees, saplings and windmills above a slope of 3.3%. This means that a tree 100 metres from the strip end must not be any higher than 3.3 metres. Any obstacle in the approach of take off areas reduces the length available for landing and take off.
Strip width and obstacle clear approach areas are to comply with the diagram under Airstrip construction.
Strip markers assist the pilot in identifying where it is safe to land. Specially made fiberglass cone markers are the best however tractor or truck tyres painted white are sufficient. Cone markers or tyres should be placed at 90 metre intervals along the edges of the landing strip which is 45 metres wide.
If white painted tyres are used, ensure they are clearly visible because collision with them will damage the aircraft
Cone markers can be purchased from:
Fabri Glass Moulding, 18 Lawson Street Coffs Harbour, NSW 2450
Phone/Fax: 02 6652 5325, Email: email@example.com
Pilots must be able to identify the wind direction and a wind sock is the best method. In emergencies when no wind sock is available, other means such as a specially prepared and contained smoke fire can be used.
Wind socks are available from:
Fabri Glass Moulding (contact details above)
Rocklea Canvas, PO Box 114 Archerfield QLD 4108, Phone: 07 3277 2845 Fax: 07 3277 0296
Aero Associates, PO Box 239, Cooma NSW 2630
Freecall: 1800 022277