The Big Picture

Operations within the circuit at a non-controlled aerodrome can result in high workload with a number of competing priorities; fly the aircraft, configure for landing, pre-landing checks, fly an accurate circuit pattern. All whilst building a picture of the location and intentions of other traffic.

PRE-FLIGHT CONSIDERATIONS

We want to give ourselves the best opportunity for success by preparing ourselves prior to start-up, or before we enter the vicinity of an aerodrome. We can start this process by understanding the local procedures at our airport, or for the destination we intend to fly to. What runways might be in use based on our weather forecasts? What hazards or processes are listed in the ERSA (if applicable)?

Now that we are familiar with the operational requirements at the aerodrome, we should consider what types of operations may take place at this location. Is there gliding traffic? Is there IFR traffic? Is there skydiving or warbirds or helicopters.... the list goes on. If gliding or skydiving is taking place then there may be an increased likelihood of operations on weekends, or mid-week operations may also take place. Understanding the environment can assist us in starting to build a picture as to what we might expect, long before we get to the circuit.

PRIOR TO ENTERING THE VICINITY OF AN AERODROME

As we track to re-join the circuit, or whilst en-route prior to entering the vicinity of our destination aerodrome, it is a good opportunity to re-brief ourselves on the local procedures at our intended aerodrome. This should minimise the need for us to consider these factors once we reach the circuit. Do we have our pre-landing checklist readily available? What runway might be in use?

As we approach the vicinity of our destination (10 nautical miles) we should be switching to the CTAF radio frequency, confirming we have selected the correct frequency and that our volume is turned up, and starting to build a picture as to any other traffic that may be in the area. At 10nm it would be a standard procedure to make an inbound call addressing the destination traffic with your type, registration, location, altitude and intentions. This allows other aircraft to continue to build their picture of your location and may prompt other traffic to report their location and intentions for your visibility.

From 10 nautical miles we should be thinking about implementing sterile cockpit procedures, in other words, avoiding unnecessary tasks that are not related to safely rejoining the circuit and landing, such as discussions with passengers or other tasks that may result in distraction from our primary task.

JOINING THE CIRCUIT

As we join the circuit, we may now have an understanding of the active runway in use, based on other traffic established in the circuit. Alternatively, we may need to confirm the active runway by confirming windsock direction.

Where possible, and unless prohibited by published aerodrome procedures, we should join overhead the airfield. This will give us the best opportunity to confirm the runway in use, confirm and visually identify any other traffic in the circuit, and position ourselves to avoid a conflict with another aircraft.

Important considerations for standard circuit procedures include:

All circuits are to be conducted as a left-hand pattern, except where right-hand patterns are specified.
All turns must be made in the circuit direction for the runway in use.
Traffic established within the circuit have right of way. It is our responsibility to fit in with established traffic when joining.
Non-standard procedures such as orbits or overtaking in the circuit should be avoided. Non-standard procedures are a common contributing factor in near miss accidents.
Avoid conflicting runways - Aerodromes with multiple runways may increase the risk of a mid-air collision. All traffic should operate from a single runway to minimise the risk of collision.
Be predictable - Circuit directions, altitudes, and joining locations are standardised for a reason. A difference in altitude by 100 feet may result in you failing to visually identify other traffic, as well as them failing to identify you. Being predictable increases the likelihood of avoiding a conflict in the circuit.
Our eyes should be outside - The circuit is not the place to be distracted by our EFB or other devices. It is important to maintain an active scan of our instruments and correctly configure the aircraft for landing, but our eyes should be outside 80% of the time.
Make regular and reliable radio calls, even if you don't believe there to be any other traffic in the area. Also, prioritise active listening of other radio calls being made. If you miss a radio call made from another aircraft, it is better to ask them to "say again" than to end up in a possible conflict.

OTHER CONSIDERATIONS

WORKING TOGETHER

We have all experienced situations where other traffic may not conform with our normal circuit shape and size. Perhaps we're stuck behind a training school aircraft conducting extra wide circuits. Perhaps there is mixed traffic in the circuit operating at different speeds. Perhaps there is an IFR aircraft conducting a straight-in approach.

At the end of the day, the most important factor is that we all get home safely. This may mean we need to extend our circuit size to account for a student pilot - After all, we were all in their position at some point in our training. It may mean we have to reduce our speed to fit in with another aircraft. It may mean we need to extend downwind to allow an IFR or other larger aircraft to make a straight in approach. All too often we hear of pilots overtaking in the circuit only to then have a near miss with another aircraft which they were unaware or, or to cut off an IFR aircraft on final approach because legally they had right of way. The reality here is that we are flying because it's something we enjoy - Why do we need to rush the last 2 minutes of the flight?

Working together and understanding the needs and procedures of other aircraft can help us all stay apart. It is not enough to work in isolation and expect someone else to keep out of our way. The current slogan of a NZ CAA safety campaign on near miss events is: Work Together, Stay Apart. Positive airmanship can lead a long way to improving safe operations for everyone within the vicinity of an aerodrome!

RADIO CALLS

it is a legal requirement to carry a radio when you are:

Above 5000feet in Class G airspace
In the vicinity of certified or military aerodromes
Operating in a Mandatory Broadcast Area (MBA)

It is a legal requirement to make a radio call when:

In the vicinity of a non-controlled aerodrome where the pilot considers it necessary to broadcast to avoid the risk of a collision with another aircraft.

It is recommended to ALWAYS make radio calls:

Before take-off or during taxiing
Inbound to an aerodrome, at least 10nm from the aerodrome (or further for high performance aircraft or busy aerodromes)
When overflying of operating in the vicinity of an aerodrome where you do not intend to land, at least 10nm from the aerodrome.

Recommended radio calls at a non-controlled aerodrome when there is other traffic include:

Entering a runway
Joining a circuit, including the intended joining method (crosswind, downwind, base)
Once clear of an active runway

The following standard broadcast format should be followed:

Location Traffic (e.g. 'Parkes Traffic')
Aircraft Type (e.g. 'Jabiru')
Callsign (e.g. 'twelve thirty-four')
Position, Level, Intentions (e.g. 'One-zero miles north, inbound on descent through 4,200, estimating circuit at time three six')
Location (e.g. 'Parkes')

LOOKOUT

As pilots should be aware, the human eye has a number of limitations that can make it extremely difficult to visually identify other aircraft. This is another reason it is important to maintain standard circuit procedures and altitudes so that pilots are more likely to visually identify you in the circuit.

An article on alerted see and avoid by Flight Safety Australia states that;

To effectively scan for conflicting traffic, use short, regularly-spaced eye movements that bring successive areas of the sky into your central visual field.

Each movement should not exceed 10 degrees, and each area should be observed for at least one second. Develop a pattern that works for you and stick to it. You may need to move your head to see beyond window posts and any other obstructions, such as pilots or passengers in the adjacent seat/s.

If you do the maths, a complete 180 degree horizontal and 30 degree vertical scan using this method could take at least 54 seconds. US military research found that it takes a pilot 12.5 seconds to avoid a collision after target detection. There can therefore be considerable time gaps in which traffic is not detected during a normal scan period.

(Image source: https://www.aopa.org/training-and-safety/online-learning/safety-spotlights/collision-avoidance/the-scan)

TRAFFIC INFORMATION AND ADS-B

Traffic information displayed on an EFBs or other devices can provide valuable assistance to alerted see and avoid, HOWEVER, we must be aware of their limitations and avoid over-relying on this technology or allowing it to distract us in the circuit.

Being aware of another aircraft based on traffic information may lead us to becoming fixated on visually identifying that target. This may result in us failing to identify that there is other traffic in the circuit that is not appearing on our traffic displays. Traffic information display on an EFB relies on maintaining active cellular service unless a compatible ADS-B device is fitted. These are valuable tools for all pilots, but we must avoid relying solely on this information.

HEMISPHERICALS / CRUISING LEVELS

In an age where GPS allows us to fly more accurately than ever, it is more important that we maintain proper altitudes when flying to avoid collision with opposite direction traffic.

Remember, in Australia, for VFR flying a track of 000-179 degrees, fly odds plus 500 (e.g. 3500ft); 180-359 degrees, fly evens plus 500ft (e.g. 4500ft).

All of these actions can assist us in building the big picture with regards to circuit activity and other traffic in order to reduce the risk of a mid-air collision.

More information on radio procedures in non-controlled airspace is available in the CASA Be Heard, Be Seen, Be Safe Publication by CLICKING HERE

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