Cessna 340, VH-FYF and a Aeronautica Macchi S.p.A, 9 km S Williamtown, Aero., 29 June 2000

A Cessna 340 (C340) was maintaining 8,000 ft while tracking
direct to Williamtown from a position bearing 020 degrees at 25 NM.
A Royal Australian Air Force Macchi was conducting a Tacan approach
and intended to perform a missed approach procedure before climbing
to 10,000 ft to continue the training sortie. The sector controller
had issued the approach controller with a restriction for the
Macchi to maintain 7,000 ft on departure to ensure separation with
the C340. The approach controller was a trainee being supervised by
a rated officer.

While the Macchi was on final approach to runway 30, a further
restriction of 2,000 ft was placed on the departure due to other
conflicting aircraft. The crew of the Macchi contacted the approach
controller on departure and advised that they were maintaining
2,000 ft. The controller took appropriate action to resolve the
confliction and then cleared the crew of the Macchi to climb to
their planned level of 10,000 ft. The controller had omitted to
issue the 7,000 ft restriction even though it was still a
requirement to ensure separation with inbound aircraft.

As the Macchi climbed through 8,000 ft, while approximately 6 NM
south of Williamtown, it passed within 1 NM of the C340. There was
an infringement of separation standards.

The investigation by the Directorate of Flying Safety -
Australian Defence Force revealed that the Australian Defence Air
Traffic System (ADATS) was being trialled at the time but that the
older surveillance radar (SURAD) equipment was actually in use by
the approach controller. The SURAD did not have identification
labels or height information (facilities that were available on
more modern equipment) and that limitation increased the workload
on the controller. Additionally, the SURAD was unreliable in its
ability to provide constant, accurate position information within
10 NM of Williamtown. The controllers were aware of those
restrictions as they were documented in aeronautical
publications.

The military sector controller was using the Interim Radar
Display System (IRDS). Although that system had labels and a Mode
"C" height reading capability, the Macchi was not equipped with a
Mode "C" capability. Consequently, the sector controller did not
have a radar indication of the height of the Macchi.

The airspace was divided vertically between approach/departures
and sector control with ground level to 5,000ft being owned by
approach/departures, and sector control the airspace above. The
coordination had been adequate but flight progress strip management
made the task of remembering an additional restriction more
complicated. Consequently, the trainee approach controller forgot
to issue the 7,000ft requirement to the crew of the Macchi. The
rated officer did not pick up the error until the Macchi was
actually passing the level of the C340. The training officer said
that he looked at the radar and the strips but was feeling tired
and may have missed the information.

The management of the flight progress strip, which was very
crowded and difficult to read, was different from that used in
other Australian locations. Local procedures were being taught
where level restrictions were placed in box 11, whereas in all
other air traffic control units the box for such notation was box
4, as specified in the Manual of Air Traffic Services (MATS). That
local procedure had been in use at Williamtown for some time, but
the investigation was unable to find any documentation specifying
such action. In addition, the strip had been divided into four
quarters to cater for four separate approaches that the crew of the
Macchi had intended to carry out. That action made the writing very
small and difficult to read. The alternate method was to use
separate flight progress strips for each approach, resulting in
more writing space being available for instructions and, therefore,
allowing for larger print.