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Recommendation issued to: Civil Aviation Safety Authority

Recommendation details
Output No: R19980119
Date issued: 20 August 1998
Safety action status:
Background:

SUBJECT - SAFETY IMPLICATIONS OF CIRCUIT DIRECTION CHANGES AT BALLINA AIRPORT


SAFETY DEFICIENCY

Since the circuit direction for runway 06 at Ballina has been changed from right to left, aircraft conducting standard downwind and base legs are operating at less than 500 ft above ground level. This change has increased the chance of a controlled flight into terrain accident, particularly at night.


FACTUAL INFORMATION

Background

Ballina City Council submitted a request to the then Coffs Harbour office of the Civil Aviation Safety Authority (CASA), that the circuit direction for runway 06 at Ballina airport be changed from right to left. The request was approved and implemented with minimal consultation with industry.


Terrain

The approach plate for Ballina shows a total of three obstacles, all north of the extended centreline and all within 3NM of the aerodrome reference point. They are located at positions roughly coincident with downwind, base and final turns for a left circuit on runway 06. The highest of these (shown as 515 ft on the approach plate and 577 ft on the Visual Terminal Chart), is an obstacle situated at an approximate base turn position, 2.5NM from the threshold of runway 06, and thus within the performance category B circling area. As the approach procedure for Ballina prohibits circling north of the extended centreline of the runway, all visual manoeuvring following an instrument approach by day or night would be carried out south of the runway. Ballina airport, in its current location, began operating in the mid-1980s. Right circuits were in use when 06 was the duty runway, until the change of circuit direction was implemented by a revision of the Enroute Supplement Australia issued in September 1997. While the Ballina file does not suggest any reason for the original choice of circuit direction, the Bureau was advised that it was most likely because of terrain considerations.


Local traffic

The Visual Terminal Chart indicates that ultralight aircraft operate north of the runway, and hang gliders operate from Lennox Head, just under 3NM north-east of the aerodrome reference point.


Ground proximity warning system alerts

A ground proximity warning system (GPWS) is a useful tool that assists pilots in maintaining situational awareness. When an aircraft is established outside set parameters of radio altitude, glideslope and localiser deviation, vertical speed, indicated airspeed, and aircraft configuration, the system activates an aural warning which suggests a course of action to the crew. However, the effectiveness of the system is diminished if crews do not follow its guidance quickly. Occasionally, the GPWS has activated when aircraft have been on a downwind leg for landing at Ballina. When a GPWS alert is activated at night, a go-around is required in accordance with company policy, as crews have few other situational cues available for them to assess their position relative to the ground.


Consultation

The Ballina Council submitted the request for a circuit direction change in order to distribute aircraft noise more evenly over Ballina township and to standardise the direction in accordance with the Aeronautical Information Publication (AIP) Ops 46.1.1. Ansett was the only operator approached prior to the circuit direction being changed. However, as the company operates its aircraft at a standard circuit height of 1,500 ft, a left circuit does not bring their aircraft in close proximity to terrain. Ansett aircraft departing from runway 06 at Ballina conduct a right circuit after climbing straight ahead to 1,500 ft, so as to allow the crew sufficient time to obtain airways clearance prior to entering controlled airspace. At least two other commercial companies regularly conduct commercial operations at Ballina, using turbo-propeller aircraft, on passenger-carrying and freight services. These operators use aircraft that conduct circuits at the standard height of 1,000 ft and were not consulted prior to the change being made.

The Regional Airspace Users Advisory Committee is an industry group that meets regularly with CASA and Airservices to discuss airways and airspace issues. CASA maintains an established process with this committee which requires consultation prior to airspace changes being implemented in all but urgent safety-related matters. The change of circuit direction proposal was not tabled before this committee or any other appropriate industry representative group. The Civil Aviation Act Part II, Paragraph 16 refers to the responsibilities of the regulator in these circumstances. It states that "in the performance of its functions and the exercise of its powers, CASA must, where appropriate, consult with government, commercial, industrial, consumer and other relevant bodies and organisations (including the International Civil Aviation Organisation and bodies representing the aviation industry)."


ANALYSIS

With substantial areas of high terrain to the north of Ballina, and virtually none to the south, it is clear that right circuits on runway 06 provide the greatest terrain clearance and is therefore the safest option for circuits at Ballina. While normal circuits over terrain are in use at other aerodromes, it is preferable that a clearly safer option be used if it is available. The hang-gliding and ultralight operations that take place north of Ballina are also a hazard to aircraft regularly transiting the area.

Any normal operation that results in the activation of the GPWS is a hazard, as crews are more likely either to ignore future warnings or try to assess their validity prior to responding. The warning system is an effective defence against a controlled flight into terrain accident, but only if the crew heed the warning and respond promptly.

Consultation with parties that have been affected by the change, was minimal prior to the circuit direction change being implemented and did not follow the intent of the Civil Aviation Act or the established process with the Regional Airspace Users Advisory Committee. A request for a circuit direction change based on standardising the direction in accordance with the AIP, and on noise issues, could not be considered an urgent safety-related matter nor a matter that was inappropriate for consultation. Whilst the Civil Aviation Act does not require such consultation in every circumstance, it appears there was a lack of appreciation of all the safety implications of changing the circuit direction of runway 06. Had effective consultation taken place, the safety issues may have become apparent and resulted in a different course of action being taken that may have satisfied both safety and environmental concerns.

One option that could be considered is that operators could amend standard operating procedures for circuits at Ballina such that they are to be flown at 1,500 ft. This would increase the terrain clearance. However, this creates an "orphan" procedure; a circuit pattern that pilots may be less familiar with when flying, and which would subsequently increase the chance of an unstabilised approach. This is of particular concern at night or in conditions of poor visibility, as crews have few external visual cues that assist in maintaining normal rates of descent and manoeuvres for the aircraft type. An unstabilised approach is a hazard, and every effort should be made to avoid creating conditions where they are more likely to develop. A safer option would be to change to right circuits for night operations, while retaining left circuits for day operations. This procedure is currently used at a number of airfields in Australia, including Port Augusta and Cootamundra.

Output text

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority review the decision to implement left circuits for aircraft operating from runway 06 at Ballina.

Initial response
Date issued: 20 April 1999
Response from: Civil Aviation Safety Authority
Action status: Closed - Accepted
Response text:

CASA has referred the recommendation to the NSW RAPAC for action.

 
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Last update 01 April 2011