Mooney Aircraft Corp M20J, VH-UDD

Local safety actions

The ERSA was amended to advise frequency management instructions
for crews entering Tamworth class "C" and "D" airspace from
adjacent class "G" airspace.

During the course of this investigation Airservices Australia
approved the installation of a tower situational awareness display
(TSAD) in Tamworth Tower. The TSAD will display transponder
equipped aircraft, within radar coverage, operating in the Tamworth
control area and CTR. The TSAD is expected to be installed in July
2002.

Additionally, Airservices Australia has commenced a review of
airspace boundaries on map displays with a view to reducing
possible misinterpretation.

The Mooney pilot did not comply with AIP procedures.

The pilot of the Mooney was an IFR pilot who should have been
able to establish, from the information available, that Tamworth
control area was class "C" airspace above 4,500 ft. He should also
have known that he required an airways clearance prior to entering
class "C" airspace. Had the pilot requested a clearance on any of
the frequencies referred to in the ERSA or depicted on the charts,
he would have been provided with the correct Tamworth ATC frequency
on which to establish two-way radio contact and obtain an airways
clearance. Two-way radio contact between Tamworth ATC and the pilot
of the Mooney would have enabled Tamworth ATC to apply separation
standards in accordance with MATS.

The relevant AIP's did not specify the vertical boundary between
Tamworth control area and the overlying Brisbane sector. That
omission may have made it difficult for the Mooney pilot to
determine the correct ATC frequency on which to establish two-way
radio contact with Tamworth ATC.

The Brisbane sector controller did not provide traffic
information to Tamworth ATC about the Mooney because he had no
reason to suspect that the Mooney was in Tamworth controlled
airspace without an airways clearance. Provision of facilities that
would have enabled Tamworth ATC to better determine the disposition
of aircraft within and around Tamworth controlled airspace may have
assisted Tamworth ATC to provide a separation standard between the
Mooney and the Saab.

A Saab SF340B aircraft (Saab) departed Tamworth aerodrome and
was tracking to the southeast on climb to flight level (FL) 120. A
Mooney Aircraft Corporation M20J (Mooney) was travelling in the
opposite direction en route from Bankstown to Inverell via Scone
and Tamworth at 8,500 ft. The Mooney was in Tamworth class "C"
controlled airspace. The Saab crew received a traffic alert from
that aircraft's traffic alert and collision avoidance system as the
Saab was approaching 8,000 ft. The Saab crew levelled their
aircraft at 8,200 ft and rolled the aircraft to the left to avoid
the Mooney. The pilot of the Mooney did not request or obtain an
airways clearance from the Tamworth Aerodrome Controller (ADC) to
enter Tamworth control area prior to the occurrence. The Saab
passed within 1.8 nautical miles (NM) horizontally and 300 ft
vertically of the Mooney. The required separation standard was
either 1,000 ft vertically or a minimum horizontal distance
determined using the appropriate "Lateral Separation" table in the
Manual of Air Traffic Services (MATS). There was an infringement of
separation standards.

Tamworth Air Traffic Control (ATC) provided a non-radar, or
procedural control, service to aircraft operating within the
Tamworth control area and control zone (CTR). Controllers used
non-radar information to establish and maintain procedural
separation standards in accordance with MATS. Tamworth class "C"
control area steps extended to 36NM when above 6,500 ft AMSL to the
south-southeast of the Tamworth aerodrome in the area that
encompassed the flight path of the Mooney. Class "G" non-controlled
airspace surrounded the Tamworth CTR and control area.

The Saab crew was conducting a scheduled fare-paying passenger
flight under instrument flight rules (IFR) and had been cleared by
the Tamworth ADC to climb to FL120. The standard altitude Tamworth
ATC could assign to aircraft leaving Tamworth control area and
entering the overlying Brisbane sector in accordance with the
letter of agreement between Tamworth ATC and Brisbane ATC, was
FL120 (subject to other aircraft). Otherwise, a procedural
separation standard was applied by Tamworth ATC and coordinated
with the Brisbane sector controller, or responsibility for
separation was specifically assigned to the Brisbane sector
controller.

The pilot of the Mooney was an IFR pilot and was normally
provided with radio frequency management instructions by ATC along
the route. On this flight however, the pilot of the Mooney was
operating under visual flight rules (VFR) and no such advice was
provided. All aircraft crews that planned to enter class "C"
controlled airspace, whether operating under IFR or VFR, were
required to establish two-way radio contact with ATC and obtain an
airways clearance prior to entering class "C" airspace. The
Tamworth visual terminal chart (VTC) depicted the lateral
boundaries of class "C" control area surrounding Tamworth aerodrome
above 4,500ft AMSL. However, neither the VTC nor the Aeronautical
Information Publication (AIP) En-Route Supplement Australia (ERSA)
specified the vertical boundary between Tamworth control area and
the overlying Brisbane sector. The pilot later reported that he had
studied the Jeppessen low altitude en-route chart relevant to
Tamworth, prior to the flight, and believed that he would not
require an ATC clearance to enter Tamworth control area above
6,500ft AMSL.

Airservices Australia reported that the Brisbane sector
controller had seen the occurrence on that controller's air
situation display (ASD) in the Brisbane Air Traffic Services Centre
and had received a short term conflict alert (STCA) from The
Australian Advanced Air Traffic System (TAAATS). The Brisbane
sector controller reported that STCA's between aircraft operating
within Tamworth control area were common but did not necessarily
indicate a potential infringement of separation standards. Short
term conflict alerts, in those circumstances, occurred when the
procedural separation standard being used by Tamworth ATC was less
restrictive than the STCA activation parameters used in TAAATS.

Although the track symbol and a label, showing the secondary
surveillance radar code and the altitude from the Mooney, were
displayed to the Brisbane sector controller on the ASD, the
Brisbane sector controller had no control or jurisdiction over the
Mooney and was not aware that the pilot had not established two-way
radio contact with Tamworth ATC. The Brisbane sector controller was
also not aware that the pilot had not received an airways clearance
to enter Tamworth control area. The Brisbane sector controller
believed both aircraft were under the control of Tamworth ATC
because both aircraft were within the Tamworth control area. The
Tamworth ADC was unable to provide a separation service to the Saab
in relation to the Mooney as he had no information on that
aircraft.