Flight Details
On 11 March 2020, a Cessna 404 aircraft, registered VH-OZO, operated by Air Connect Australia, was conducting a passenger charter flight from Cairns to Lockhart River, Queensland, under instrument flight rules. The aircraft carried one pilot and four passengers. Weather conditions included areas of cloud and rain that significantly reduced visibility at Lockhart River Airport.
First Approach
The pilot conducted an area navigation (RNAV) global satellite system (GNSS) instrument approach to runway 30. The approach followed a recommended 3° constant descent profile. The aircraft descended through the minimum descent altitude (MDA) of 730 ft and passed the missed approach point (MAPt). At approximately 400 ft, the pilot initiated a missed approach. The indicated airspeed during the latter part of the first approach was about 140 kt, exceeding the operator's preferred speed of about 110 kt after the final approach fix (FAF) and the operator's stabilized approach criteria speed at 300 ft above aerodrome elevation. The reason for the missed approach could not be determined.
Second Approach
Immediately after the missed approach, the pilot commenced a second RNAV GNSS approach to the same runway. During this approach, the pilot descended from 3,500 ft approximately 2.7 NM before the intermediate fix (or 12.7 NM before the MAPt). The descent followed a roughly 3° flight path but was about 1,000 ft below the recommended descent profile. The aircraft continued descending below the MDA and collided with terrain 6.4 km (3.5 NM) short of the runway. The pilot and four passengers sustained fatal injuries, and the aircraft was destroyed.
ATSB Findings
The ATSB determined that the aircraft probably entered areas of significantly reduced visibility during the second approach, with heavy rainfall at the airport after the first approach. No evidence suggested pilot medical issues, incapacitation, or aircraft system anomalies; the aircraft was in controlled flight until impact. The accident was very likely controlled flight into terrain (CFIT). The specific reason for the aircraft descending 1,000 ft below the recommended profile could not be determined, but the pilot did not effectively monitor altitude and descent rate for an extended period. Additionally, the aircraft exceeded the operator's lateral navigational tolerance after the FAF, which should have prompted a missed approach. The aircraft's speed after the FAF increased to 140 kt and later to 150 kt.
The pilot was likely under high workload during the second approach due to factors including immediate re-entry, a different approach method, lateral tracking corrections, and higher-than-appropriate speeds. The pilot had the required qualifications and regularly logged RNAV GNSS approaches, but almost all were in visual meteorological conditions, with limited recent experience in instrument conditions.
Aircraft Equipment
The aircraft was not fitted with a terrain avoidance and warning system (TAWS). If installed and operational, it would have provided visual and aural alerts of approaching terrain during the second approach. There was no Australian requirement for piston-engine aeroplanes like VH-OZO to be equipped with TAWS, though the Civil Aviation Safety Authority (CASA) had been considering changes since 2008. The aircraft had two Garmin GNS 430W GPS units with a terrain awareness function, but it was not equivalent to TAWS, and it could not be determined if the function was enabled. These units did not provide vertical guidance during non-precision approaches.
Conclusion
The investigation found no evidence of organizational or commercial pressures on the pilot to complete the flight. Sufficient fuel was available for the trip and return with holding. Self-imposed pressures or incomplete procedural knowledge could not be reliably assessed. The accident highlights risks associated with CFIT, particularly for smaller operators, and the availability of means to mitigate such risks.