The Brisbane Ocean sector controller saw on radar an
unidentified aircraft climbing through flight level (FL)180. The
controller issued traffic information to the crew of a Dash 8
operating an instrument flight rules (IFR) flight from Lord Howe
Island to Sydney at FL200. The crew of the Dash 8 sighted the
unidentified aircraft at an approximate distance of 5 NM and 1,500
ft below them. The two aircraft passed with 3 NM lateral separation
at the same level. The unidentified aircraft was subsequently
identified as an Astra conducting an IFR calibration flight. It
appeared that the crew of the Astra had not complied with
Aeronautical Information Publication (AIP) procedures for changing
levels in non-controlled airspace. These procedures require pilots
of IFR category aircraft operating in non-controlled airspace to
notify the relevant air traffic agencies of any changes in
altitude/level. Investigation of the occurrence revealed that the
Astra crew were not notified of a change in airspace management for
the their area of operations.
The Astra crew was conducting a calibration of a new radar that
had been installed at Williamtown aerodrome. This required the
aircraft to track outbound from Williamtown at 1,500 ft, in a
direction clear of local operating areas and air routes, until
radar coverage was lost and then return on the reciprocal track
while climbing. Once the next altitude or level was reached the
crew would immediately turn the aircraft to track outbound again.
The manoeuvre was to be repeated at 10,000 ft, FL200, FL300 and
FL400 and would conclude with the aircraft completing the task at
approximately 220 NM from Williamtown.
The Astra crew had prepared and dispatched written briefs on the
task to Williamtown and Brisbane Air Traffic Control (ATC)
agencies. However, the calibration task schedule was amended and
subsequently conducted 24 hours earlier than originally notified.
The brief depicted the calibration flight as being a series of
steps with an increase in altitude/level as the distance from
Williamtown increased but did not depict that the aircraft would
fly the reciprocal track at any stage. After the Astra had departed
Williamtown to commence the calibration, the Williamtown approach
coordinator briefed the Brisbane Flight Service International
officer on the task, based on the briefing and other details as
subsequently advised by the crew.
The general practice of the Astra crew was to conduct personal
briefings with the responsible air traffic control staff on the day
of a calibration task and this was their intention on the day of
the occurrence. However, when the Astra arrived at Williamtown, the
senior air traffic control officer who had planned to attend the
briefing was not available. Consequently, the crew only briefed a
technical ground party.
The Astra crew was issued a clearance by Williamtown Air Traffic
Control to track via the 100 tactical air navigation aid radial on
climb to FL210. On this track the Astra would transit Williamtown
restricted area R577 which was promulgated as continuously active,
24 hours a day. The intended track of the Astra entered and exited
R577 respectively at 25 NM and 130 NM east of Williamtown. The
vertical limits for the area are from sea level to FL600. When not
required for military operations a notice to airman (NOTAM)
deactivating R577 for specific periods was normally issued by
Williamtown Air Traffic Control. A deactivation NOTAM was not
issued for the period of the calibration flight.
As an aid to airspace management, Brisbane and Williamtown Air
Traffic Control agencies had agreed to automatically release
portions of R577 and other restricted areas to Brisbane when the
restricted areas were active. This agreement was published in the
Northern New South Wales Manual of Air Traffic Services Supplement
(MATS SUPP) which in turn was part of both Williamtown and Brisbane
operating procedures. The agreement effectively transferred
airspace management responsibility for the south-east portion of
R577, known as the Jordy Release, from Williamtown Air Traffic
Control to Brisbane Centre. The planned track of the Dash 8 passed
through the Jordy Release.
The lateral and vertical limits for Australian airspace were
published in the Airservices Australia Designated Airspace Handbook
(DAH) and depicted on AIP charts. The DAH, charts or a NOTAM can be
used for flight crew pre-flight briefing. None of the documents
included the MATS SUPP provisions.
A letter of agreement between Brisbane Ocean sector, Brisbane
Flight Service International and Sydney Flight Service 4 detailed
the airspace management responsibilities for the Jordy Release when
transferred to Brisbane Centre. The division of responsibilities
was:
- Ocean sector
That portion of the release above FL200 between 90 NM and 150 NM
from Sydney and above FL245 outside of 150 NM Sydney,
- Flight Service International
That portion of the release at FL200 and below that level outside
of 90 NM from Sydney, and
- Sydney Flight Service 4
That portion of the release below the control area steps inside 90
NM from Sydney.
The Ocean sector controller was required to separate IFR
aircraft as if they were in controlled airspace. The officers of
both flight service units were required to issue traffic
information to pilots of IFR category flights, just as they would
have for pilots of IFR flights in non-controlled airspace, in
accordance with the Manual of Air Traffic Services (MATS) criteria.
Part of the MATS criteria required traffic information to be issued
when aircraft were climbing or descending through the level of
another aircraft when these aircraft were within 15 NM or 10
minutes longitudinally or laterally. Ocean sector uses radar and
procedural control methods to separate aircraft. Radar coverage
extends to beyond the eastern limit of R577. Neither of the flight
service units had access to radar services.
Because of the flexible airspace management arrangements for the
Jordy Release, flight service international officers usually
pre-empted requests for confirmation of the availability of planned
routes for aircraft inbound to Sydney. Normal practice was to
advise crews as early as possible when the area was active with
military operations to enable them to commence tracking via
alternative routes. The crew of the Dash 8 was not advised that
their planned route was unavailable. The crew was subsequently
advised to contact the Ocean controller at 140 NM from Sydney for a
clearance.
The Astra crew reported that due to R577 being active, they
believed that, their flight would be managed by Williamtown air
traffic control. The Williamtown coordinator advised flight service
international that the crew had been cleared to FL210 but that
initially they would maintain 1,500 ft. The coordinator
subsequently advised flight service international that the Astra
had climbed to 10,000 ft. The Astra crew was instructed that they
were leaving the Williamtown restricted area and to transfer to
flight service international on high frequency (HF) radio. This was
required as they were operating in that portion of R577 being
managed by flight service international.
After several attempts, the Astra crew contacted flight service
international on HF radio and was advised of another HF frequency
to use if they were having communication difficulties. There was no
further contact with the crew on HF radio. The flight service
international officer attempted unsuccessfully to contact the crew.
The problems with the HF radio communication were believed to be
the result of propagation difficulties. Once it was apparent to the
crew that HF communication was not viable they tried to establish
communications with Brisbane Centre via VHF. The crew reported
after the occurrence that because they were unable to advise any
air traffic service agency of the next climb, from 10,000 ft to
FL200, they broadcasted their intention on the VHF emergency
frequency, 121.5 MHz. The investigation could not establish whether
other crews heard the transmission.
The crew contacted the Nambucca Sector Controller and reported
that their position was 120 NM east of Williamtown on the 100
radial and that the aircraft had left 10,000 ft on climb to FL200.
The Nambucca controller confirmed that the Astra was tracking west
and that at 110 NM from Williamtown the crew would commence a turn
to track outbound. The Nambucca controller contacted the Ocean
controller to report the Astra's position. At approximately the
same time the Ocean controller was issuing a clearance to the crew
of EA261 and shortly after noticed an unidentified aircraft
approaching the Dash 8. The Nambucca controller issued traffic
information to the crew of the Astra, who arrested the climb of
their aircraft and then descended to FL185.
The Astra crew did not select the radio failure code of the
aircraft's secondary surveillance radar transponder. The
investigation did not establish why the crew did not change the
transponder code.
