Sikorsky Aircraft S-76C, VH-EXU

The pilot in command of a Sikorsky (S-76C) helicopter reported
that an aircraft had passed the helicopter at the same level, with
200-300 ft lateral separation, while operating in the vicinity of
East Sale aerodrome. The aircraft was subsequently identified as a
RAAF HS-748, callsign Hudson 505. At the time of the occurrence,
East Sale airspace was uncontrolled, and Mandatory Broadcast Zone
(MBZ) procedures were in place on frequency 118.3 MHz.

The S-76C had departed Longford Heliport, located approximately
7 NM south of East Sale. It was proceding to East Sale on climb to
2,500 ft above ground level (AGL) to conduct a practice instrument
landing system (ILS) approach for runway 22. Another RAAF HS-748,
callsign Hudson 24, was operating in the circuit at East Sale and
preparing to conduct an ILS approach for runway 22.

As the S-76C approached East Sale, the crew of Hudson 24
broadcast that they were turning inbound on the ILS, and would be
making a full stop landing. At about the same time, the crew of
Hudson 505 broadcast that they were departing to the north-east of
East Sale and passing 1,700 ft AGL. However, Hudson 505 was
actually to the south-west of the aerodrome, and was turning to the
left to track back over the East Sale non-directional beacon (NDB)
prior to its departure to the north-east.

The S-76C crew, believing that Hudson 505 was north-east of East
Sale and clear of their approach, continued inbound to overhead the
East Sale NDB. When the S-76C was approximately 3 nm south of the
East Sale NDB, maintaining 2,500 AGL, the crew observed Hudson 505
passing in front of the S-76C from left to right, at the same level
and in close proximity. At the same time Melbourne Centre called
Hudson 505 on frequency 124.0 MHz and advised the crew that
unidentified traffic was half a mile to the south-west of the
aircraft. The crew of Hudson 505 subsequently reported that they
did not see the S-76C.