Oceania

Conclusions:
- The pilot was appropriately licensed and was being supervised as required by Civil Aviation Rules.
- The aircraft had been maintained in accordance with the requirements of Civil Aviation Rules, and had a valid airworthiness certificate.
- There was no evidence that the aircraft had suffered any mechanical problem which may have contributed to the accident.
- The probable initiator of the accident was a hung load of lime which would have limited the climb performance of the aircraft. Factors contributing to the accident were the steep rising terrain and a high tree line which restricted the turning options for the pilot.
- The pilot flew the aircraft into a situation where he had limited recovery options. Due to his limited agricultural flying experience, he may not have appreciated his predicament until it was too late or taken recovery action early enough. The aircraft appears to have aerodynamically stalled during a right hand turn from which there was insufficient height to recover.
- In addition, the pilot’s decision making ability and concentration may have been impaired to some degree by various distractions and fatigue.
- The accident was not survivable.
- The standard sight (observation) window installed on Fletcher aircraft is an impractical method for pilots to monitor the upper level of the hopper contents during flight, particularly with a product like lime which has a higher relative density compared to other fertiliser products.

Failure of the port flap jack linkage eye-bolt which caused an asymmetrical flap condition, causing the aircraft to be out of control.

Contributing factors:
• A line of thunderstorms crossed the aircraft’s intended track.
• The aircraft was operating in the vicinity of thunderstorm cells.
• In circumstances that could not be determined, the aircraft’s load limits were exceeded, causing structural failure of the airframe.
Other safety factors:
• Air traffic control procedures, did not require the SIGMET information to be passed to the aircraft.
• There were shortcomings in the Airservices Australia Hazard Alert procedures and guidelines for assessing SIGMET information.
• Air traffic control procedures for the dissemination of SIGMET information contained in the Aeronautical Information Publication were inconsistent with procedures contained in International Civil Aviation Organization (ICAO) Doc. 4444 and ICAO Doc. 7030.
Other key findings:
• The aircraft was not equipped with weather radar or lightning strike detection systems.
• The pilot did not make any request for additional information regarding the weather to air traffic services.
• The pilot in command was occupying the right cockpit seat and the observer- pilot the left cockpit seat at the time of the breakup, but that arrangement was not considered to have influenced the development of the accident.

Findings are listed in order of development and not in order of priority.
- The pilot was correctly licensed, experienced and authorised for the flight.
- The pilot was operating the aircraft in an unserviceable condition because of a stuck airspeed indicator, which prevented him accurately assessing the aircraft airspeed. Consequently the
aircraft could have exceeded its airspeed limitations by some degree in the turbulent conditions.
- The structural integrity of the vertical fin had been reduced to such an extent by a cluster of unnoticed pre-existing fatigue cracks in its leading edge that eventual failure was inevitable. When the fin failed, it brought about an unrecoverable loss of control and the accident.
- Although the early design of the vertical fin met recognised requirements, it did not provide for any structural redundancy and the leading edge of the fin (a structural component) was not
damage-tolerant.
- The cracks in the fin leading edge went unnoticed until the failure, most likely because an approved black rubber anti-abrasion strip along that surface had prevented any detailed examination of it.
- The approved maintenance programmes did not reflect the inspection-dependent nature of the vertical fin for its ongoing airworthiness, with the inspection periods having been extended over
the years without full consideration given to the importance of frequent inspections for timely detection of fatigue damage.
- There was no evidence that the fitment of a more powerful STC-approved turbine engine, in place of a piston engine, had initiated the fatigue cracks in the fin leading edge. However, once
started, the extra engine power might have contributed to the rate of propagation of the cracks.
- The vertical fin defects and failures in the Fletcher aircraft over the years were not confined to turbine-powered aircraft.
- The CAA’s STC approval process for the turbine engine installation was generally robust and had followed recognised procedures, but the process should have been enhanced by an in-depth
evaluation of the fatigue effects on the empennage.
- Given the generally harsh operating environment and frequency of operations for the turbine powered Fletcher, the continued airworthiness requirements of the fin were not scrutinised as
robustly as they should have been during the STC approval process. Consequently the maintenance programmes had not been improved to ensure the ongoing structural integrity of the fin.

Findings:
• There were no indications prior to, or during the flight, of problems with any aircraft systems that may have contributed to the circumstances of the occurrence.
• The pilot continued flight into forecast and known icing conditions in an aircraft not approved for flight in icing conditions.
• The global navigation satellite constellation was operating normally.
• The pilot did not comply with the requirements of the published instrument approach procedure.
• The pilot was known, by his Chief Pilot and others, to adopt non-standard approach procedures to establish his aircraft clear of cloud when adverse weather conditions existed at Mount Hotham.
• The pilot may have been experiencing self-imposed and external pressures to attempt a landing at Mount Hotham.
• Terrain features would have been difficult to identify due to a heavy layer of snow, poor visibility, low cloud, continuing heavy snowfall, drizzle, sleet and approaching end of daylight.
• The pilot’s attitude, operational and compliance practices had been of concern to some Airservices’ staff.
• The operator’s operational and compliance history was recorded by CASA as being of concern, and as a result CASA staff continued to monitor the operator. However, formal surveillance of the operator in the preceding two years had not identified any significant operational issues.
Significant factors:
• The weather conditions at the time of the occurrence were extreme.
• The extreme weather conditions were conducive to visual illusions associated with a flat light phenomenon.
• The pilot did not comply with the requirements of flight under either the instrument flight rules (IFR) or the visual flight rules (VFR).
• The pilot did not comply with the requirements of the published instrument approach procedure and flew the aircraft at an altitude that did not ensure terrain clearance.
• The aircraft accident was consistent with controlled flight into terrain.

Contributing factors relating to occurrence events and individual actions:
- The crew commenced the Lockhart River Runway 12 RNAV (GNSS) approach, even though the crew were aware that the copilot did not have the appropriate endorsement and had limited experience to conduct this type of instrument approach.
- The descent speeds, approach speeds and rate of descent were greater than those specified for the aircraft in the Transair Operations Manual. The speeds and rate of descent also exceeded those appropriate for establishing a stabilised approach.
- During the approach, the aircraft descended below the segment minimum safe altitude for the aircraft's position on the approach.
- The aircraft's high rate of descent, and the descent below the segment minimum safe altitude, were not detected and/or corrected by the crew before the aircraft collided with terrain.
- The accident was almost certainly the result of controlled flight into terrain.

Contributing factors relating to local conditions:
- The crew probably experienced a very high workload during the approach.
- The crew probably lost situational awareness about the aircraft's position along the approach.
- The pilot in command had a previous history of conducting RNAV (GNSS) approaches with crew without appropriate endorsements, and operating the aircraft at speeds higher than those specified in the Transair Operations Manual.
- The Lockhart River Runway 12 RNAV (GNSS) approach probably created higher pilot workload and reduced position situational awareness for the crew compared with most other instrument approaches. This was due to the lack of distance referencing to the missed approach point throughout the approach, and the longer than optimum final approach segment with three altitude limiting steps.
- The copilot had no formal training and limited experience to act effectively as a crew member during a Lockhart River Runway 12 RNAV (GNSS) approach.

Contributing factors relating to Transair processes:
- Transair's flight crew training program had significant limitations, such as superficial or incomplete ground-based instruction during endorsement training, no formal training for new pilots in the operational use of GPS, no structured training on minimising the risk of controlled flight into terrain, and no structured training in crew resource management and operating effectively in a multi-crew environment. (Safety Issue)
- Transair's processes for supervising the standard of flight operations at the Cairns base had significant limitations, such as not using an independent approved check pilot to review operations, reliance on passive measures to detect problems, and no defined processes for selecting and monitoring the performance of the base manager. (Safety Issue)
- Transair's standard operating procedures for conducting instrument approaches had significant limitations, such as not providing clear guidance on approach speeds, not providing guidance for when to select aircraft configuration changes during an approach, no clear criteria for a stabilised approach, and no standardised phraseology for challenging safety-critical decisions and actions by other crew members. (Safety Issue)
- Transair had not installed a terrain awareness and warning system, such as an enhanced ground proximity warning system, in VH-TFU.
- Transair's organisational structure, and the limited responsibilities given to non-management personnel, resulted in high work demands on the chief pilot. It also resulted in a lack of independent evaluation of training and checking, and created disincentives and restricted opportunities within Transair to report safety concerns with management decision making. (Safety Issue)
- Transair did not have a structured process for proactively managing safety related risks associated with its flight operations. (Safety Issue)
- Transair's chief pilot did not demonstrate a high level of commitment to safety. (Safety Issue)

Contributing factors relating to the Civil Aviation Safety Authority processes:
- CASA did not provide sufficient guidance to its inspectors to enable them to effectively and consistently evaluate several key aspects of operator management systems. These aspects included evaluating organisational structure and staff resources, evaluating the suitability of key personnel, evaluating organisational change, and evaluating risk management processes. (Safety Issue)
- CASA did not require operators to conduct structured and/or comprehensive risk assessments, or conduct such assessments itself, when evaluating applications for the initial issue or subsequent variation of an Air Operator's Certificate. (Safety Issue)

Other factors relating to local conditions:
- There was a significant potential for crew resource management problems within the crew in high workload situations, given that there was a high trans-cockpit authority gradient and neither pilot had previously demonstrated a high level of crew resource management skills.
- The pilots' endorsements, clearance to line operations, and route checks did not meet all the relevant regulatory and operations manual requirements to conduct RPT flights on the Metro aircraft.
- Some cockpit displays and annunciators relevant to conducting an instrument approach were in a sub-optimal position in VH-TFU for useability or attracting the attention of both pilots.

Other factors relating to instruments approaches:
- Based on the available evidence, the Lockhart River Runway 12 RNAV (GNSS) approach design resulted in mode 2A ground proximity warning system alerts and warnings when flown on the recommended profile or at the segment minimum safe altitudes. (Safety Issue)
- The Australian convention for waypoint names in RNAV (GNSS) approaches did not maximise the ability to discriminate between waypoint names on the aircraft global positioning system display and/or on the approach chart. (Safety Issue)
- There were several design aspects of the Jeppesen RNAV (GNSS) approach charts that could lead to pilot confusion or reduction in situational awareness. These included limited reference regarding the 'distance to run' to the missed approach point, mismatches in the vertical alignment of the plan-view and profile-view on charts such as that for the Lockhart River runway 12 approach, use of the same font size and type for waypoint names and 'NM' [nautical miles], and not depicting the offset in degrees between the final approach track and the runway centreline. (Safety Issue)
- Jeppesen instrument approach charts depicted coloured contours on the plan-view of approach charts based on the maximum height of terrain relative to the airfield only, rather than also considering terrain that increases the final approach or missed approach procedure gradient to be steeper than the optimum. Jeppesen instrument approach charts did not depict the terrain profile on the profile-view although the segment minimum safe altitudes were depicted. (Safety Issue)
- Airservices Australia's instrument approach charts did not depict the terrain contours on the plan-view. They also did not depict the terrain profile on the profile-view, although the segment minimum safe altitudes were depicted. (Safety Issue)

Other factors relating to Transair processes:
- Transair's flight crew proficiency checking program had significant limitations, such as the frequency of proficiency checks and the lack of appropriate approvals of many of the pilots conducting proficiency checks. (Safety Issue)
- The Transair Operations Manual was distributed to company pilots in a difficult to use electronic format, resulting in pilots minimising use of the manual. (Safety Issue) Other factors relating to regulatory requirements and guidance
- Although CASA released a discussion paper in 2000, and further development had occurred since then, there was no regulatory requirement for initial or recurrent crew resource management training for RPT operators. (Safety Issue)
- There was no regulatory requirement for flight crew undergoing a type rating on a multi-crew aircraft to be trained in procedures for crew incapacitation and crew coordination, including allocation of pilot tasks, crew cooperation and use of checklists. This was required by ICAO Annex 1 to which Australia had notified a difference. (Safety Issue)
- The regulatory requirements concerning crew qualifications during the conduct of instrument approaches in a multi-crew RPT operation was potentially ambiguous as to whether all crew members were required to be qualified to conduct the type of approach being carried out. (Safety Issue)
- CASA's guidance material provided to operators about the structure and content of an operations manual was not as comprehensive as that provided by ICAO in areas such as multi-crew procedures and stabilised approach criteria. (Safety Issue)
- Although CASA released a discussion paper in 2000, and further development and publicity had occurred since then, there was no regulatory requirement for RPT operators to have a safety management system. (Safety Issue)
- There was no regulatory requirement for instrument approach charts to include coloured contours to depict terrain. This was required by a standard in ICAO Annex 4 in certain situations. Australia had not notified a difference to the standard. (Safety Issue)
- There was no regulatory requirement for multi-crew RPT aircraft to be fitted with a serviceable autopilot. (Safety Issue)

Other factors relating to Civil Aviation Safety Authority processes:
- CASA's oversight of Transair, in relation to the approval of Air Operator's Certificate variations and the conduct of surveillance, was sometimes inconsistent with CASA's policies, procedures and guidelines.
- CASA did not have a systematic process for determining the relative risk levels of airline operators. (Safety Issue)
- CASA's process for evaluating an operations manual did not consider the useability of the manual, particularly manuals in electronic format. (Safety Issue)
- CASA's process for accepting an instrument approach did not involve a systematic risk assessment of pilot workload and other potential hazards, including activation of a ground proximity warning system. (Safety Issue) Other key findings An 'other key finding' is defined as any finding, other than that associated with safety factors, considered important to include in an investigation report. Such findings may resolve ambiguity or controversy, describe possible scenarios or safety factors when firm safety factor findings were not able to be made, or note events or conditions which 'saved the day' or played an important role in reducing the risk associated with an occurrence.
- It was very likely that both crew members were using RNAV (GNSS) approach charts produced by Jeppesen.
- The cockpit voice recorder did not function as intended due to an internal fault that had developed sometime before the accident flight and that was not discovered or diagnosed by flight crew or maintenance personnel.
- There was no evidence to indicate that the GPWS did not function as designed.
- There would have been insufficient time for the crew to effectively respond to the GPWS alert and warnings that were probably annunciated during the final 5 seconds prior to impact with terrain.

Findings are listed in order of development and not in order of priority.
- The flight crew was appropriately licensed and rated for the aircraft, and qualified for the flight.
- The captain was experienced on the type and the operation, and approved as a line training captain, while the FO was recently trained and not very experienced on the type.
- The aircraft had a valid Certificate of Airworthiness and records indicated that it had been maintained in accordance with its airworthiness requirements. There were no relevant deferred
maintenance items prior to dispatch of the accident flight.
- Although the aircraft had been refuelled in one tank only, it probably took off with the fuel balanced within limits.
- Some fuel imbalance led the captain to decide to carry out further fuel balancing while the aircraft was in cruising flight.
- The captain’s instructions to the FO while carrying out fuel balancing resulted in the aircraft being flown at a large sideslip angle by the use of the rudder trim control while the autopilot was engaged.
- The FO’s reluctance to challenge the captain’s instruction may have been due to his inexperience and underdeveloped CRM skills.
- The autopilot probably disengaged automatically because a servo reached its torque limit, allowing the aircraft to roll and dive abruptly as a result of the applied rudder trim.
- The crew was unable to recover control from the ensuing spiral dive before airspeed and g limits were grossly exceeded, resulting in the structural failure and in-flight break-up of the aircraft.
- The in-flight fire which occurred was a result of the break-up, and not a precursor to it.
- The applied rudder trim probably contributed to the crew’s inability to recover control of the aircraft.
- The crew’s other control inputs to recover from the spiral dive were not optimal, and contributed to the structural failure of the aircraft.
- The flying conditions of a dark night with cloud cover below probably hindered the crew’s early perception of the developing upset.
- The AFM limitation on use of the autopilot above 20 000 ft should have led to the crew disconnecting it when climbing the aircraft above that altitude.
- The crew’s non-observance of this autopilot limitation probably did not affect its performance, or its automatic disengagement.
- If the aircraft had been manually flown during the fuel-balancing manoeuvre, the upset would probably have not occurred.
- The operator should detail the in-flight fuel balancing procedure as a written SOP for its Metro aircraft operation.
- The AFM for the SA 226/227 family of aircraft should include a limitation and warning that the autopilot must be disconnected while in-flight fuel balancing is done, and should include a procedure for in-flight fuel balancing.

For reasons that could not be determined, the aircraft commenced a slight left angle of bank and drifted left after lift-off at a height from which the pilot was unable to recover prior to striking trees to the left of the runway.

Controlled flight into terrain.