Oceania

Examination of the accident site indicated that the aircraft’s engine was delivering power at the time of impact. Wreckage examination did not reveal evidence of any defect or mechanical failure that would have contributed to the event. Although the post-mortem report on the pilot noted that he had significant coronary atherosclerosis, there was insufficient information available to determine whether pilot incapacitation was involved in the accident. The investigation did not identify any organisational or systemic issues that might adversely affect the future safety of aviation
operations.

Contributing safety factors:
• The weather was marginal for flight under the visual flight rules, with broken cloud forecast down to 500 ft above mean sea level in the area.
• The pilot, who did not hold a command instrument rating, entered instrument meteorological conditions because he was adhering to an un-written operator rule not to fly below 1,000 ft above ground level.
• The pilot became lost in cloud and flew the aircraft towards the Mt Strzelecki Range, exiting the cloud in very close proximity to the terrain.
• The aircraft exited the cloud in a small valley, within which the pilot could neither turn round nor out-climb the terrain.
Other key findings:
• The aircraft exited cloud before impacting terrain and with sufficient time for the pilot to execute a forced landing.
• The design of the aircraft’s seats, and the provision to passengers in the GA-8 Airvan of three-point automotive-type restraint harnesses with inertia reel shoulder straps contributed to the passengers’ survival, almost without injury.

Findings:
- There were no technical defects identified that may have contributed to the accident and the aeroplane was considered controllable during the take-off roll, with the engine able to deliver power during the short flight.
- The aeroplane’s centre of gravity was at least 0.122m rear of the maximum permissible limit, which created a tendency for the nose to pitch up. The most likely reason for the crash was the aeroplane being excessively out of balance. In addition, the aeroplane probably became airborne early and at too low an airspeed to prevent uncontrollable nose-up pitch.
- The aeroplane reached a pitch angle that would have made it highly improbable for the unrestrained parachutists to prevent themselves sliding back towards the tail. Any shift in weight rearward would have made the aeroplane more unstable.
- The engineering company that modified ZK-EUF for parachuting operations did not follow proper processes required by civil aviation rules and guidance. Two of the modifications had been approved for a different aircraft type, one modification belonged to another design holder and a fourth was not referred to in the aircraft maintenance logbook.
- The flight manual for ZK-EUF had not been updated to reflect the new role of the aeroplane and was limited in its usefulness to the aeroplane owner for calculating weight and balance.
- Regardless of the procedural issues with the project to modify ZK-EUF, the engineering work conducted on ZK-EUF to convert it from agricultural to parachuting operations in the standard category was by all accounts appropriately carried out.
- The weight and balance of the aeroplane, with its centre of gravity at least 0.122m outside the maximum aft limit, would have caused serious handling issues for the pilot and was the most significant factor contributing to the accident.
- ZK-EUF was 17 kg over its maximum permissible weight on the accident flight, but was still 242 kg lighter than the maximum all-up weight for which the aeroplane was certified in its previous agricultural role. Had the aeroplane not been out of balance it is considered the excess weight in itself would have been unlikely to cause the accident. Nevertheless, the pilots should have made a full weight and balance calculation before each flight.
- The aeroplane owner and their pilots did not comply with civil aviation rules and did not follow good, sound aviation practice by failing to conduct weight and balance calculations on the aeroplane. This resulted in the aeroplane being routinely flown overweight and outside the aft centre of gravity allowable limit whenever it carried 8 parachutists.
- The empty weight and balance for ZK-EUF was properly recorded in the flight manual, but the stability information in that manual had not been appropriately amended to reflect its new role of a parachute aeroplane. Nevertheless, it was still possible for the aeroplane operator to initially have calculated the weight and balance of the aeroplane for the predicted operational loads before entering the aeroplane into service.
- The aeroplane owner did not comply with civil aviation rules and did not follow good, sound aviation practice when they: used the incorrect amount of fuel reserves; removed the flight manual from the aeroplane; and did not formulate their own standard operating procedures before using the aeroplane for commercial parachuting operations.
- The Director of Civil Aviation delegated the task of assessing and overseeing major modifications to Rule Part 146 design organisations and individual holders of “inspection authorisations”. The delegations did not absolve the Director of his responsibility to monitor compliance with civil aviation rules and guidance.
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- The delegations increased the risk that unless properly managed the CAA could lose control of 2 safety-critical functions: design and inspection. The Director had not appropriately managed that risk with the current oversight programme.
- The CAA had adhered strictly to its normal practice and was acting in accordance with civil aviation rules when approving the change in airworthiness category from special to standard. However, knowing the scope, size and complexity of the modifications required to change ZK-EUF from an agricultural to a parachuting aeroplane, it should have had greater participation in the process to help ensure there were no safety implications.
- There was a flaw in the regulatory system that allowed an engineering company undertaking major modification work on an aircraft to have little or no CAA involvement by using an internal or contracted design delegation holder and a person with the inspection authorisation to oversee and sign off the work.
- The level of parachuting activity in New Zealand warranted a stronger level of regulatory oversight than had been applied in recent years.
- The CAA’s oversight and surveillance of commercial parachuting were not adequate to ensure that operators were functioning in a safe manner.
- The CAA had mechanisms through the Director’s powers under the Civil Aviation Act and his designated powers under the HSE Act to effectively regulate the parachuting industry pending the introduction of Rule Part 115.
- An alcohol and drug testing regime needs to be initiated for persons performing activities critical to flight safety, to detect and deter the use of performance-impairing substances.
- In this case the impact was not survivable and the passengers wearing safety restraints would not have prevented their deaths, but in other circumstances the wearing of safety restraints might reduce injuries and save lives.
- Safety harnesses or restraints would help to prevent passengers sliding rearward and altering the centre of gravity of the aircraft. It could not be established if this was a factor in this accident.

Contributing safety factors:
• The operator’s processes for determining the aircraft’s required landing distance did not appropriately consider all of the relevant performance factors.
• The operator’s processes for learning and implementing change from the previous runway overrun incident were ineffective.
• The flight crew did not use effective crew resource management techniques to manage the approach and landing.
• The crew landed long on a runway that was too short, affected by a tailwind, had a degraded surface and was water contaminated.
• The crew did not carry out a go-around during the approach when the visibility was less than the minimum requirements for a visual approach.
• The baulked landing that was initiated too late to assure a safe takeoff.
Other safety factors:
• The aircraft aquaplaned during the landing roll, limiting its deceleration.
• The runway surface was described as gravel, but had degraded over time.
• The weather station anemometer was giving an incorrect wind indication.

Contributing safety factors:
• While the aircraft was climbing to 9,000 feet the right engine sustained a power problem and the pilot subsequently shut down that engine.
• Following the shutdown of the right engine, the aircraft's descent profile was not optimized for one engine inoperative flight.
• The pilot conducted a descent towards Bankstown Airport that was consistent with a normal arrival profile without first verifying that the aircraft was capable of achieving adequate performance with one engine inoperative.
• Following the engine problem, the aircraft's flightpath and the pilot’s communication with air traffic control indicated that the pilot's situation awareness was less than optimal.
• The aircraft collided with a powerline support pole on the eastern side of the intersection of Sackville Street and Canley Vale Road, Canley Vale, about 6 km north-west of Bankstown Airport.
Other safety factors:
• The pilot did not broadcast a PAN following the engine shutdown and did not provide air traffic control with further information about the nature of the problem in order for the controller to positively establish the severity of the situation.
• Section 4 of Civil Aviation Advisory Publication (CAAP) 5.23-2(0), Multi-engine Aeroplane Operations and Training of July 2007 did not contain sufficient guidance material to support the flight standard in Appendix A subsection 1.2 of the CAAP relating to Engine Failure in the Cruise. [Minor safety issue]
Other key finding:
• Given the pilot’s extensive experience and testing in the PA-31 aircraft type, and subsequent endorsement training on a high performance turboprop multi-engine aircraft since the issue by CASA in 2008 of a safety alert in respect of the pilot’s PA-31 endorsement, it was unlikely that any deficiencies in that endorsement training contributed to the accident.

• The pilot in command initiated a simulated left engine failure just after becoming airborne and at a speed that did not allow adequate margin for error.
• The pilot in command simulated a failure of the left engine by selecting flight idle instead of zero thrust, thereby simulating a simultaneous failure of the left engine and its propeller autofeather system, instead of a failure of the engine alone.
• The pilot under check operated the aircraft at a speed and attitude (bank angle) that when uncorrected, resulted in a loss of control.
• The pilot under check increased his workload by increasing torque on the right engine and selecting the yaw damper.
• The pilot in command probably became preoccupied and did not abandon the simulated engine failure after the heading and speed tolerance for the manoeuvre were exceeded and before control of the aircraft was lost.

From the evidence available it was evident that the engine had a substantial in-flight oil leak, which necessitated the in-flight shut down of the engine and a diversion to the nearest available airstrip. The accident damage to the engine in the area of the apparent oil leak precluded a conclusive finding as to the source of the leak. Although the detailed examination of the oil tube attachment lug fracture surfaces was inconclusive, the oil tube remained the most likely source of the oil leak. Evidence from other oil tube failures indicated that significant vibratory loading can cause the oil tube attachment lugs to fracture in the manner observed in the oil tube fitted to VH-NTQ. There was no evidence that the transfer tube was subjected to vibration from a compressor turbine or power turbine blade failure or of an incorrectly fitted engine mount. There was also no evidence of a pre-accident defect that would have caused a reduction in actual engine torque.