Fokker B.V. F27 MK 50 , VH-FNB

Local safety action

Following the investigation, Airservices Australia has:

Withdrawn the use of OPD coordination between the tower and TMA and, restricted the use of Local Instruction 8-22-TM for use between TMA positions.
Briefed controllers to pass sequence information to tower as per Local Instructions 8-23TM in a timely manner and to ensure that handover/takeover procedures are carried out as per local instructions 1-5-TM.
Instructed TWR and TMA Team Leaders to promote team work across streams at all times and ensure each unit provides back up support at all times, especially during quiet periods.
Added a section to local instructions for the control of overshooting aircraft including an instruction to provide a "next" call to DEP for all aircraft conducting overshoot at Perth.
Instructed controllers to pass the current clearance issued to aircraft operating within 5nm of Perth airport to the ADC by the TMA controllers. However this does not absolve the ADC from obtaining information which may be pertinent to separation responsibilities.

The approach controller, by issuing departure instructions without reference to the Departures controller, did not comply with local instructions.
The aerodrome controller accepted overshoot instructions that placed the two aircraft in close proximity.
The aerodrome controller did not provide assistance to the departure and approach controllers with regard to aircraft operating within close proximity to the aerodrome.
The sole reliance on the use of Operational Data Information for coordination left room for ambiguity to exist in the controllers understanding of an aircraft's intended track.

The information flow between the approach and departures controllers was not in accordance with local instructions, because approach was issuing overshoot instructions for an aircraft that would require a clearance from departures. The aerodrome controller, by coordinating with approach instead of departures, compounded this and may have reduced the departures controllers' situational awareness.

The use of Operational Data Information for coordination between units was accepted as a standard operating procedure. On some occasions the overuse and over reliance on Operational Data Information coordination may lead to a lack of situational awareness. Controllers were aware of what was intended to happen after the overshoot but there were no visual cues as to what the aircraft was doing. The approach and departures controllers coordinated via hotline for Departures to retain the Cessna on frequency and place the aircraft on a close right downwind. However there was no way for the aerodrome controller to know this unless the controller had queried the aircraft's current clearance. This may have led the approach controller to discount the Cessna from his mental traffic picture.

A Fokker 50 was conducting a practice Instrument Landing System
(ILS) approach for runway 24 at Perth, with an intended overshoot
to Cunderin. A Cessna 172 was tracking via Northam to Perth with an
intended overshoot to Jandakot. Other traffic in the area at the
time was a helicopter tracking from Perth to Mundijong.

At 1133 Western Standard Time the crew of the Fokker was
conducting the overshoot onto a radar heading which placed the
aircraft in close proximity to the Cessna. The pilot of the Cessna
sighted the Fokker and turned and descended to avoid that
aircraft.

Perth Air Traffic Control had two runway specific traffic
management plans. These were North-East (duty runways 03/06) and
South-West (duty runways 21/24). Airspace ownership changed
dependent on the plan in use and the airspace was divided as
Terminal Control Area South (TMA S) and Terminal Control Area North
(TMA N), the division occurring along the 281/077 radials from the
Perth VOR. At the time of the occurrence the plan placed North-East
and TMA S under the control of approach (APP) and TMA N under the
control of departures (DEP).

The Perth Aerodrome Controller (ADC) had assumed responsibility
for the Aerodrome control position approximately 10 minutes prior
to the occurrence. The departure controller had received a handover
10 minutes prior to the incident and was unaware that the Fokker
would turn back towards the Cessna.

The relative positions and intended tracks of both the Fokker
and the Cessna were such that the departure controller was required
to maintain vertical separation until within approximately 5 NM of
the aerodrome, with the Fokker passing under the Cessna near
Parkerville.

The aerodrome controller coordinated with the approach
controller for departure instructions for the helicopter. The
approach controller issued the instruction "right unrestricted you
separate all the inbounds". The aerodrome controller accepted this
and the instructions were issued without reference to the departure
controller. The aerodrome controller subsequently coordinated with
the approach controller for the overshoot instructions for the
Fokker. The approach controller issued the instruction "left 120
unrestricted", but shortly after revised the instruction to,
"separate with the helicopter, or keep him on runway heading for a
bit to get him above". The aerodrome controller advised that the
left turn onto a heading of 120 degrees would suffice. The approach
controller issued the overshoot instruction without reference to
the departure controller.

Coordination between the tower controllers and the Terminal
Control Area controllers utilises the Operational Data Information
contained within the radar label display. Coordination between
approach and departures is via hotline communications.

Temporary Local Instruction (TLI) SDW/98/160 page 47 Section 5
paragraph 12.3 provides a choice of units to coordinate for
aircraft overshooting Perth with the proviso "as appropriate." That
section was contained in a letter of agreement between the Tower
and Terminal Control Area and specifically dealt with overshooting
aircraft.

The same TLI at page 65 Section 6 paragraph 2.1.1 advised that
"In all instances the next call must be to DEP". This instruction
was headed "Management of Departing IFR Aircraft-Perth" and dealt
with Perth Departures from the non-duty runway. That paragraph
specifically required the aerodrome controller to coordinate with
the departures controller for departure instructions on aircraft
departing from the non-duty runway but did not mention the
procedure to be followed for overshooting aircraft from the
non-duty runway.