Traffic mix CAAP 166-01(4.1)
Non-controlled aerodromes can host a variety of operations including passenger air transport in large jet and turboprop aircraft, glider, parachute, helicopter, gyroplane, ultralight, balloon and agricultural operations. This diversity presents a range of potential safety risks that are mitigated through the adoption of a standard code of conduct and good airmanship.
Turboprop or jet aircraft passenger operations – At certain non-controlled aerodromes, regular public transport passenger, corporate and charter companies may utilise large turboprop or jet aircraft. These aircraft may have different operating parameters/criteria to those of many general aviation aircraft. They fly under IFR and are generally operated in accordance with company SOPs. Pilots of large aircraft flown at slow speeds with a high nose angle may find it difficult to see other smaller aircraft below their flight path, particularly on approach. These aircraft will broadcast their intentions, but it is essential that pilots of smaller aircraft also make and respond to broadcasts and do not simply assume that the larger aircraft is aware of their position.
General aviation pilots should be aware that, in certain circumstances, passenger transport aircraft may not be able to use the active runway. Passenger transport aircraft must operate under more stringent regulations, including specific aircraft performance regulations. For example, an aircraft may depart downwind, accepting an increased take off distance because of a performance limitation imposed by terrain clearance requirements on the active runway. Similarly, landing into wind may not always be possible when relevant performance limitations are taken into account.
Glider operations – can be conducted from normal runways associated with an aerodrome, or from adjacent sites within the confines of an aerodrome. Gliders can be launched using a variety of methods including aero tow, vehicle tow, self-propulsion and winch launch. In all cases, vehicles and people may be operating on, or in the vicinity of, the runways in use.
Where gliders are operating from the active runway, they may not be able to give way to other aircraft when landing.
A double white cross displayed adjacent to the windsock indicates that gliding operations are in progress. Aeronautical charts also use the double cross to indicate areas where glider operations take place. Some gliders operating adjacent to the CTAF area may use a different frequency to the CTAF or area frequency.
Winch operations may occur at any aerodrome and launch gliders to 4000 ft AGL, although the typical height is between 1500 and 2000 ft AGL. Pilots should be aware of winch wires up to these levels, particularly when overflying the aerodrome, and check ERSA and the latest NOTAMs for current, specific operational information.
Gliders landing on the active runway may not be able to give way to other aircraft. At aerodromes with both glider and helicopter operations, helicopter pilots should follow the standard traffic patterns to avoid gliders which may be flying modified circuit patterns.
Parachuting operations – Aeronautical charts depict parachute symbols at aerodromes where known parachute operations occur. ERSA also details the aerodromes where parachute operations take place. Pilots should consult the latest NOTAMs for any additional information.
In Australia, parachuting operations are permitted through cloud in certain circumstances.
Pilots flying parachuting operations will broadcast on all relevant frequencies. For example, if the jump commences in Class G airspace and will land at a non-controlled aerodrome, advisory calls will be made on both the area frequency and the CTAF.
Parachutists in free-fall are almost impossible to see, so pilots are advised to avoid overflying an aerodrome with an active drop zone. Communication with the parachuting drop aircraft is essential to avoid flying into a drop zone area.
Helicopters and gyroplanes operations – Helicopters can arrive at and depart aerodromes in various directions. Helicopter pilots can choose to fly a circuit similar to a fixed-wing aircraft, but may also fly a circuit either in or contra to the circuit direction at a height of at least 500 ft above the aerodrome elevation and closer to the runway. This can only be done if the associated landing site is outside the Operations – Non-controlled aerodromes – Traffic mix ASAVFRG Version 5.0 | visit vfrg.casa.gov.au regularly for updates 3.45 runway strip in use; the non-standard circuit does not cross the extended centreline of the runway in use and pilots broadcast their intentions. Check the relevant ERSA entry for any noise abatement procedures.
Helicopters may turn on to their departure heading at any height after take-off, provided it is safe to do so. When approaching to land at a marked helipad or suitable clear area, helicopter pilots should avoid the flow of fixed-wing aircraft. Helicopters must avoid other circuit traffic at all times.
Other pilots should be aware that, for some helicopter operations, the only suitable landing area is the runway.
Helicopters and gyroplanes can fly more slowly than fixed-wing aircraft and approach to land at steeper angles. Both helicopters and gyroplanes can be expected to practise power-off landings (autorotations) which involve a very steep approach and high rate of descent.
As helicopter and gyroplane operations can be varied and flexible, pilots need to ensure that they monitor and advise other aircraft of their position and intentions by radio.
Ultralight operations – The term ‘ultralight’ applies to many small recreational aircraft including trikes, powered parachutes and other small fixed-wing aircraft that cruise at maximum speeds of about 55 kt. Pilots of these aircraft should conduct their standard circuit at 500 ft above aerodrome elevation.
Entry to the circuit should be at 500 ft above aerodrome elevation as it is normally impractical to overfly the field above all other circuit traffic. Joining the circuit at 500 ft above aerodrome elevation will ensure adequate separation from higher and faster traffic.
Ultralight aircraft pilots who choose to use the overfly procedure above the circuit altitude should be aware that:
- ultralight aircraft are difficult to see, particularly for faster, larger aircraft
- faster, larger aircraft create significant wake turbulence that can be extremely hazardous to ultralight aircraft
- faster, larger aircraft will not be able to slow to the speeds of an ultralight aircraft to follow the ultralight and
- faster, larger aircraft—before arriving in the circuit and when below 10,000 ft – can be operating at speeds up to 250 kt. Although aircraft should be operating at a maximum of 200 kt in the circuit, such an aircraft reporting at 20 nm from an aerodrome could be in the vicinity of the circuit within five minutes.
Ultralight pilots should consult the AIP, ERSA, relevant charts and the latest NOTAMs to obtain the most up-to-date information and procedures at their aerodrome. The VFRG website vfrg.casa.gov.au is also updated regularly.
Aerial application operations – Pilots should be aware that aerial application operations are conducted from some non-controlled aerodromes.
Aerial application operations frequently involve low-level manoeuvring after takeoff and before landing. These low level manoeuvres do not have to conform to the standard traffic circuit. However, pilots of other aircraft can expect aerial application aircraft to:
- maintain a listening watch and broadcast their intentions on the CTAF and
- give priority to other traffic.
The rules governing these operations include provisions for separation from RPT flights, as specified in CASRs 137.155 and 137.160.
Balloons – Aerodromes at which hot air balloons operate are marked on charts with the balloon symbol. Balloons, cannot of course, fly a circuit. Powered aircraft must give way to balloons.
Balloon pilots can operate only in the vicinity of a certified or registered aerodrome if they have completed the Australian Balloon Federation’s airfield operations check. They must broadcast their position and intentions on the CTAF.
Balloons may approach the aerodrome on a different track to the one they intend for landing to take advantage of changing wind directions at different altitudes. Not all landings are from straight-in approaches and other pilots should be aware that the balloon may change direction quite quickly as it descends.