The pilot of a piper Archer was cleared for final by the
Terminal Area (TMA) controller for a practice runway 35 Instrument
Landing System (ILS) approach at Canberra. The duty runways at
Canberra were 17 and 12. A Saab 340, VH-KDQ, had recently departed
from Canberra using runway 17 when the Canberra surface movement
controller (SMC) recognised that it was tracking in the opposite
direction towards the Archer which was on final approach. The TMA
controller took action to resolve the situation by instructing the
pilot of the Archer to turn away from the ILS approach. The Archer
was at about 8 NM on final approach at 4,500ft while KDQ was 2 NM
upwind leaving 3,000ft on climb. The Canberra aerodrome controller
(ADC) dept KDQ on frequency until he observed on radar that the
Arhcer was turning and then instructed the crew of KDQ to contact
the TMA controller.
The separation standard required between aircraft was either 3
NM laterally or 1,000ft vertically. Examination of recorded radar
data indicated that the distance between the aircraft was about 4
NM laterally and 1,100ft vertically at the closest point of
approach. There was no infringement of separation standards.
The TMA controller had moved the electronic flight strip for the
Archer into the traffic management window of The Australian
Advanced Air Traffic System (TAAATS) display, indicating that the
aircraft was to carry out the ILS approach. The movement of the
electronic strip into the traffic management window automatically
indicated the pending arrival of the aircraft to the ADC in
Canberra Tower. The ADC annotated the electronic strip with a
"back-slash", which indicated an acknowledgment of the pending
transfer.
Six aircraft had been issued airways clearances for departure
from Canberra. The TMA controller was aware of the pending
departures but he was not aware of when they would be ready for
take-off. Two of those aircraft, Impulse 935 and VH-KJQ,
subsequently taxied and the ADC advised the TMA controller that he
was releasing those aircraft. Auto release procedures, which were
in operation at the time, authorised the ADC to clear aircraft for
take-off on pre-determinded departure tracks after advising the TMA
controller of the pending release. Auto release procedures were
designed to minimise voice coordination between the TMA controller
and ADC. Under auto release procedures, dependence was placed on
the ADC to ensure that there was sufficient spacing between
successive departing aircraft to enable the TMA controller to
establish and maintain the required separation standard. The ADC
advised the TMA controller that the Archer could "have the ILS"
after those two aircraft, while also reiterating that there were a
number of additional pending departures.
By the time KJQ had become airborne, a further three aircraft
had taxied for departure: Eastern 832, Impulse 917 and KDQ. The ADC
advised the TMA controller that two of the aircraft were
approaching the holding point and one was just leaving the parking
apron. The ADC also instructed the TMA controller to "hold [the
Archer] out". The TMA controller did not acknowledge that
instruction nor did the ADC seek acknowledgment. The ADC
subsequently advised the TMA controller that he was releasing
"Eastern 832 followed by Impulse 917 then KDQ". The TMA controller
replied "Roger".
The TMA controller was required to annotate his electronic
flight strip with an "A" for each aircraft to signify that
auto-release coordination had been carried out. After receiving the
coordination on the latter three aircraft, the TMA controller did
not immediately annotate his electronic strips. Rather he advised
the pilot of the Archer of a further delay and provided radar
vectors for re-sequencing. When he did annotate the electronic
strips with an "A", he only annotated Eastern 832 and Impulse 917.
The controller stated later that he might have omitted to annotate
the electronic strip for KDQ by confusing that aircraft with KJQ,
the crew of which had just called the controller with a departure
report.
The TMA controller then vectored the Archer to carry out the ILS
approach after the departure of Impulse 917. After that crew had
contacted the TMA controller, the pilot of the Archer was cleared
for final for the ILS approach. By the time KDQ became airborne, a
further two aircraft had taxied and the ADC coordinated their
release with the TMA controller. The TMA controller queried that
they would be "after" the Archer, to which the ADC replied "no
they're RPT [Regular Public Transport] they've got higher priority
they are going".
The ADC and TMA controllers then entered into a discussion about
the situation that lasted about 26 seconds. During that period
neither controller seemed to understand where the aircraft under
the other person's control was in relation to the aircraft under
their control. It was not until a third party, the Canberra SMC,
intervened that the controllers understood there was a potential
conflict situation and the TMA controller then took action to
resolve the situation.
Auto-release procedures
Canberra Local Instructions stated that prior to issuing a
take-off clearance, the ADC "shall advise the TMA controller of the
pending release and receive an acknowledgment by callsign". During
this occurrence, the ADC released five aircraft: none were
acknowledged by callsign nor were callsign acknowledgments
sought.
Voice coordination - arriving aircraft
Movement of the electronic flight strip into the traffic
management window and acknowledgment of the sequence by annotating
the strip with a back-slash was normally the only coordination
required between the TMA and the ADC for an arriving aircraft.
Canberra Local Instructions stated that, in addition to the use of
the traffic management strip, the TMA controller "shall voice
coordinate when:
a) An instrument approach other than a straight-in approach to
the system arrival runway will be conducted."
Further, Canberra Local Instructions stated that use of the
reciprocal runway directions may be approved for individual
aircraft:
"a) when an aircraft is conducting a practice instrument
approach and missed approach subject to mutual agreement between
TMA and CBA [ADC]".
From the time the Archer was turned away from the ILS apprach on
the first occasion there was no mutual agreement between the
controllers for the use of the reciprocal runway and there was no
voice coordination regarding the subsequent approach for the
aircraft.
Traffic Management
The Archer pilot contacted the Melbourne Senior Terminal Area
Controller (STAC) to book a training ILS approach at Canberra. The
booking system established an order of priority for flight crews
competing for training ILS approaches. It was reported that it
would be unusual for the STAC to deny an ILS booking. It was mainly
a paperwork exercise and there were no known busy times blocked out
on the booking sheet. In this particular instance there was no
coordination between the FMA staff and Canberra tower staff
regarding the suitability of the timing of the training ILS
approach for the Archer, despite seven pending departures from the
reciprocal runway around the same time.
Organisational Issues
The Canberra TMA controllers were originally co-located with the
aerodrome function in Canberra. During that time controllers were
rotated through both TMA and aerodrome elements. In 1994, the TMA
element was relocated to Melbourne. The controllers involved in
this occurrence had 5.5 and 7 years experience respectively in
their positions at Canberra Tower and in Melbourne. During that
time, both had two familiarisation visits to each other's unit. In
both cases, one visit was prior to the transition to TAAATS and one
was as part of the transition process. Neither controller believed
that the frequency of these visits was sufficient to maintain an
appropriate level of awareness and appreciation of the other
person's working environment.
