Cairns

The accident was the consequence of a controlled flight into terrain.
The following contributing factors were identified:
• While the pilot was operating in the vicinity of Lockhart River Airport, there were areas of cloud and rain that significantly reduced visibility and increased the risk of controlled flight into terrain.
In particular, the aircraft probably entered areas of significantly reduced visibility during the second approach.
• After an area navigation (RNAV) global satellite system (GNSS) approach to runway 30 and missed approach, the pilot immediately conducted another approach to the same runway that was on a similar gradient to the recommended descent profile but displaced about 1,000 ft below that profile. While continuing on this descent profile, the aircraft descended below a segment minimum safe altitude and the minimum descent altitude, then kept descending until the collision with terrain about 6 km before the runway threshold.
• Although the exact reasons for the aircraft being significantly below the recommended descent profile and the continued descent below the minimum descent altitude could not be determined, it was evident that the pilot did not effectively monitor the aircraft’s altitude and descent rate for an extended period.
• When passing the final approach fix (FAF), the aircraft’s lateral position was at about full-scale deflection on the course deviation indicator (CDI), and it then exceeded full-scale deflection for
an extended period. In accordance with the operator’s stabilized approach procedures, a missed approach should have been conducted if the aircraft exceeded half full-scale deflection at the FAF, however a missed approach was not conducted.
• The pilot was probably experiencing a very high workload during periods of the second approach. In addition to the normal high workload associated with a single pilot hand flying an approach in instrument meteorological conditions, the pilot’s workload was elevated due to conducting an immediate entry into the second approach, conducting the approach in a different manner to their normal method, the need to correct lateral tracking deviations throughout the approach, and higher than appropriate speeds in the final approach segment.
• The aircraft was not fitted with a terrain avoidance and warning system (TAWS). Such a system would have provided visual and aural alerts to the pilot of the approaching terrain for an extended period, reducing the risk of controlled flight into terrain.
• Although the aircraft was fitted with a GPS/navigational system suitable for an area navigation (RNAV) global satellite system (GNSS) approach and other non-precision approaches, it was not fitted with a system that provided vertical guidance information, which would have explicitly indicated that the aircraft was well below the recommended descent profile. Although the operator had specified a flight profile for a straight-in approaches and stabilized approach criteria in its operations manual, and encouraged the use of stabilized approaches, there were limitations with the design of these procedures. In addition, there were limitations with other risk controls for minimizing the risk of controlled flight into terrain (CFIT), including no procedures or guidance for the use of the terrain awareness function on the aircraft’s GNS 430W GPS/navigational units and limited monitoring of the conduct of line operations.

Other factors that increased risk:
• Although an applicable height of 1,000 ft for stabilized approach criteria in instrument meteorological conditions has been widely recommended by organizations such as the International Civil Aviation Organization for over 20 years, the Civil Aviation Safety Authority had not provided formal guidance information to Australian operators regarding the content of stabilized approach criteria. (Safety issue)
• The Australian requirements for installing a terrain avoidance and warning system (TAWS) were less than those of other comparable countries for some types of small aeroplanes conducting air transport operations, and the requirements were not consistent with International Civil Aviation Organization (ICAO) standards and recommended practices. More specifically, although there was a TAWS requirement in Australia for turbine-engine aeroplanes carrying 10 or more passengers under the instrument flight rules:
- There was no requirement for piston-engine aeroplanes to be fitted with a TAWS, even though this was an ICAO standard for such aeroplanes authorized to carry 10 or more passengers, and this standard had been adopted as a requirement in many comparable countries.
- There was no requirement for turbine-engine aeroplanes authorized to carry 6–9 passengers to be fitted with a TAWS, even though this had been an ICAO recommended practice since 2007, and this recommended practice had been adopted as a requirement in many comparable countries. (Safety Issue)

Other findings:
• The forecast weather at Lockhart River for the time of the aircraft’s arrival required the pilot to plan for 60 minutes holding or diversion to an alternate aerodrome. The aircraft had sufficient fuel for that purpose; and the aircraft had sufficient fuel to conduct the flight from Cairns to Lockhart River and return, with additional fuel for holding on both sectors if required.
• There was no evidence of any organizational or commercial pressure to conduct the flight to Lockhart River or to complete the flight once to commenced.
• Based on the available evidence, it is very unlikely that the pilot was incapacitated or impaired during the flight.
• There was no evidence of any aircraft system or mechanical anomalies that would have directly influenced the accident. However, as a consequence of extensive aircraft damage, it was not possible to be conclusive about the aircraft’s serviceability.
• The aircraft was fitted with Garmin GNS 430W GPS/navigational units that could be configured to provide visual (but not aural) terrain alerts. However, it could not be determined whether the
terrain awareness function was selected on during the accident flight.

The ATSB found that the aircraft had not broken up in flight and that it impacted the water at a relatively low speed and a near wings-level attitude, consistent with it being under control at impact. It is likely that the pilot encountered rain and reduced visibility when manoeuvring to commence a visual approach. However, there was insufficient evidence available to determine why the aircraft impacted the water.
Several aspects of the flight increased risk. The pilot had less than 4 hours sleep during the night before the flight and the operator did not have any procedures or guidance in place to minimize the fatigue risk associated with early starts. In addition, the pilot, who was also the operator’s chief pilot, had either not met the recency requirements or did not have an endorsement to conduct the types of instrument approaches available at Horn Island and several other locations frequently used by the operator.

The following factors were identified:
1. The pilots of CYC were conducting in-flight familiarization training using the emergency power lever. That procedure was not contained in the aircraft manufacturer's pilot operating handbook.
2. The engine manufacturer's documentation contained information on the use of the emergency power lever, which did not preclude the use of the emergency power lever for in-flight familiarization training.
3. The engine sustained a flameout at an altitude above mean sea level from which reignition of the engine was not successfully completed.
4. Erosion of the first-stage compressor blades would have reduced the aerodynamic efficiency of the compressor blades.

The reason for the initial fuel flow fluctuations was not identified by the pilot. It is likely that the pilot assumed the zero reading indicated impending fuel exhaustion and concentrated on conducting a landing in unfamiliar terrain. During the landing approach the pilot lost control of the aircraft and it descended rapidly to the ground.

Radar data recorded by Air Traffic Services and witness reports indicated that the aircraft was flying straight and level and maintaining a constant airspeed. Therefore, it is unlikely that the aircraft was experiencing any instrumentation or engine problems. Why the pilot continued flight into marginal weather conditions at an altitude that was insufficient to ensure terrain clearance, could not be established. The aircraft was flown at an altitude that was insufficient to ensure terrain clearance.

Occurrence #1: missing aircraft
Phase of operation: unknown
Findings
1. (c) reason for occurrence undetermined
2. Operation with known deficiencies in equipment - performed - pilot in command
3. Light condition - dark night
4. Weather condition - thunderstorm
5. Weather condition - icing conditions

Both engines had failed due to fuel exhaustion. The pilot normally flew a different type of aircraft, this aircraft only being used by the company to supplement its services. For company aircraft normal route fuel requirements are specified. As a result, there was little need for him to make significant fuel calculations. On this occasion, the pilot found he had little time between his arrival at Cairns and the scheduled DEPARTURE of his next flight. He ordered that only 80 litres of fuel be added to the aircraft tanks. The calculated fuel burn for the proposed return flight to Kidston was approximately 240 litres. However, on DEPARTURE from Cairns it was estimated that only about 220 litres of fuel was in the aircraft tanks. Refuelling facilities were available at Kidston but no fuel was added to the aircraft tanks.
The following factors were considered relevant to the development of the accident:
1. The aircraft design is such that the fuel quantity can only be determined by the gauge, unless the tanks are full.
2. The preflight preparation, in relation to fuel requirements, carried out by the pilot was inadequate.
3. The pilot lacked recent experience at more complex fuel calculations.

An inspection of wreckage did not reveal any mechanical defect or failure that could have contributed to the accident. The reasons for the apparent loss of control of the aircraft could not be determined.

Inspection of the wreckage indicated that the aircraft struck the the top of a ridge line, 250 metres south-west of the highest point of the Mt Williams area. At the time, the aircraft was on a west-north-westerly heading, flying wings level and climbing at a angle of about five degrees. No fault was found with the aircraft that could have contributed to the occurrence. At the time the aircraft entered cloud, the pilot should have reverted to Instrument Flight Rules procedures. To comply with these procedures a pilot is required, inter alia, to ensure that adequate terrain clearance is achieved during climb to the lowest safe altitude. The relevant altitude for the route segment Cairns to Biboohra is 4500 feet above mean sea level (amsl). As the aircraft was apparently under control at the time of impact with the ground at about 3250 feet amsl, it was likely that the pilot had overlooked the lowest safe altitude requirements.