Recommendation

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.