Civil Aviation Authority changes its investigation practices following Ombudsman’s findings

Regulatory and investigative agencies
Ombudsmen Act 1975
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Ombudsmen Act 1975
Civil Aviation Authority
David McGee
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Complaint about investigation by Civil Aviation Authority (CAA) of a light aircraft crash—criticism of way CAA conducted investigation into the crash which resulted in 2 deaths—after O’s investigation, CAA accepted a likely cause was from a crack in a conrod (engine part) which appeared shortly after the engine had been reconditioned—O considered CAA should not have asked the reconditioning company for assessment and that CAA was unreasonable not to interview engineers during its investigation

A complaint was made to the Ombudsman about an investigation by the Civil Aviation Authority (CAA) into a light aircraft crash that had resulted in two deaths.

The CAA had formed conclusions about the reasons for the crash. The complainants considered that CAA had given insufficient weight to an alternative theory, raised by the owner of the aircraft, that the crash had been caused by failures in the assembly of the aircraft’s engine. The complainants also considered that it was unreasonable for CAA to return the engine to the company that had recently reconditioned it.

During the Ombudsman’s investigation, CAA was asked to comment on these matters. CAA noted that it was not unusual to have an engine examined by the same company that had overhauled it given the small number of overhaul companies in New Zealand. However, it did review its safety investigation into the accident and then considered that ‘the damage (small dent or nick) to the engine connecting rod (conrod) which initiated the engine failure was most probably caused during the final assembly stage of the engine overhaul process’ and that ‘it is likely in this case that correct engineering practices were not observed during the reassembly of the engine.’ However, CAA advised the Ombudsman that ‘due to the time that has passed since the initial investigation was completed, and the fact that this issue is already well documented, it is considered impractical to take any further action on this matter.’

The Ombudsman noted that these comments from CAA were not contained in the accident report at the time, rather the report stated that it is not possible to establish how and when the indent occurred’.

The Ombudsman considered that if the engineers had been interviewed at the time, more could have been said in the report about the likelihood that the damage occurred during the process of engine reassembly. It was also possible this might have led to a greater emphasis in the Airworthiness Directive (AD) on the importance of careful handling and the use of securing systems to prevent impact damage to the conrods during reassembly. In saying this, the Ombudsman acknowledged the point made by the CAA that since the AD was issued 10 years ago, there had not been another aviation accident involving this engine type due to damaged engine conrods. The Ombudsman considered that nothing could be gained during his investigation by trying to track down or interview the engineers who reassembled the engine in this accident. Too much time had passed for such interviews to be of any use even if one were able to find the specific engineers.

However, the Ombudsman considered that a more general recommendation was warranted and concluded that it should be standard practice for an investigation into an aviation accident to consider interviewing the engineers who carried out the overhaul reassembly of an engine where engine failure occurs soon after the overhaul. The Ombudsman suggested that there should be a presumption that the engineers will be interviewed in cases where engine failure occurs within 100 flying hours of the overhaul. It was accepted that a CAA investigator, having considered the matter, should still be able to decide not to interview the engineers. However, the investigator should then be required to document his or her reasons as to why interviewing the engineers was not necessary in a particular case.

The Ombudsman recommended that the CAA’s Safety Investigation Unit revise its procedures to incorporate the above standard practice. In accordance with the requirements of section 22(3) of the Ombudsmen Act, the Ombudsman wrote to the Minister of Transport providing him with a copy of his opinion.

This case note is published under the authority of the Ombudsmen Rules 1989. It sets out an Ombudsman’s view on the facts of a particular case. It should not be taken as establishing any legal precedent that would bind an Ombudsman in future.

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