When 50:50 isn’t fair: NSW Court of Appeal revisits contributory negligence

A pilot and a licensed aircraft maintenance engineer each conduct a daily inspection of the same helicopter, and both fail to identify a crack. The helicopter later suffers engine failure and crashes. Does that make them equally responsible?

The NSW Court of Appeal has said no.

In the decision of Encore Aviation Pty Ltd v O'Driscoll Aviation Pty Ltd; Encore Aviation Pty Ltd v O'Driscoll; O'Driscoll v Encore Aviation Pty Ltd [2026] NSWCA 227, the Court of Appeal heard appeals arising from a helicopter crash following fatigue related failure of the aircraft’s exhaust diffuser assembly. At first instance, both the pilot (plaintiff) and the licensed aircraft maintenance engineer were found to have conducted a daily inspection but failed to identify a visible crack. The plaintiffs’ damages were reduced by 50% for contributory negligence.

The Court of Appeal upheld the finding of contributory negligence, but considered that an equal apportionment did not adequately reflect the parties’ respective responsibility for the damage. It instead apportioned responsibility 60% to the defendant, Encore Aviation Pty Ltd, and 40% to the plaintiffs, Phillip O’Driscoll (pilot) and O’Driscoll Aviation Pty Ltd.

While the adjustment was only 10%, the reasoning is significant. The decision illustrates that even where two parties undertake the same task and fail to identify the same risk, it does not follow that they should bear equal responsibility for the resulting loss.

Background

On 17 April 2018, a helicopter owned by O'Driscoll Aviation and piloted by Mr O'Driscoll suffered engine failure while carrying out lifting operations in the Snowy Mountains. The helicopter crashed and caught fire. Mr Driscoll was seriously injured and the aircraft severely damaged. The cause of the crash was not in dispute. The experts agreed that it resulted from fatigue-related loss of the exhaust diffuser assembly.

Encore had supplied a maintenance engineer to carry out maintenance work on the helicopter. The primary judge found that both the engineer and the pilot conducted a daily inspection on the morning of the accident and should have identified a visible crack in the exhaust diffuser. Had the crack been identified, the helicopter would have been grounded and the accident avoided.

Encore was found liable, but the primary judge assessed the pilot's contributory negligence at 50%.

On appeal, the Court upheld the critical factual findings, including that the crack was visible and that the pilot had conducted a daily inspection. A principal issue, however, was whether a 50% reduction for the pilot’s contributory negligence was appropriate.

Was 50:50 the right answer?

There was an apparent symmetry to the primary judge's assessment. The engineer conducted a daily inspection and failed to identify the crack. The pilot did the same. Either could have identified the defect and prevented the helicopter from flying. However, the Court of Appeal found that the analysis should not stop there.

The assessment of contributory negligence required a comparison of the parties' culpability, being the degree of departure from the applicable standard of care, and the relative importance of their conduct in causing the damage. Although the engineer and pilot had undertaken the same task, the standards expected of them were different. The engineer’s conduct was to be assessed against the standard of a reasonably competent, licensed aircraft maintenance engineer. By comparison, the pilot was an experienced pilot who was authorised to perform a daily inspection, but was not trained as a licensed aircraft maintenance engineer.

There were also practical differences in the manner of their inspections. The engineer had a telescopic mirror and was trained to use it. The pilot had neither the mirror nor that training. The fact that both were authorised to conduct the same inspection did not mean they were equally skilled in identifying fatigue cracking.

The contractual arrangements also favoured greater responsibility being attributed to Encore. Although Encore was not required to undertake every daily inspection, it had been engaged for its maintenance expertise and had, in large part, assumed responsibility for the aircraft's maintenance and airworthiness. Additionally, the pilot undertook his inspection knowing that the engineer, who was more qualified and had been engaged to maintain the aircraft, had already carried out an inspection.

That said, there were other factors weighing in favour of the pilot bearing a substantial share of culpability. The pilot was O'Driscoll Aviation's Chief Executive Officer and Head of Flying Operations. He was the ‘key personnel’ for the purposes of s 28 of the Civil Aviation Act and, in effect, the holder of the certificate of registration under r 41 of the Civil Aviation Regulations (Regulations), with responsibility for ensuring that all required maintenance on the aircraft was carried out. He was authorised to undertake the daily inspection and signed the certificate recording that he had done so.

On the other hand, the difference in the causal importance of the parties' conduct was less pronounced. Both men were in a position to identify the crack and prevent the flight. However, once the engineer had completed his inspection of the aircraft, the Regulations did not require the pilot to undertake a separate inspection.

Weighing those matters together, the Court of Appeal found that Encore should bear more responsibility, but ‘not dramatically more’. The Court apportioned responsibility 60% to Encore and 40% to the plaintiffs.

The result illustrates an important distinction. Overlapping responsibility does not necessarily mean equal responsibility.

Why the decision matters

Although the case concerned aircraft maintenance, the reasoning has broader relevance to professional negligence claims involving overlapping responsibilities.

The Court of Appeal referred to cases involving valuers and solicitors, geotechnical engineers and builders, and structural engineers and certifying authorities. Leeming JA observed that people may be required to identify the same error or defect but nevertheless be subject to different standards because of the different skills they profess to possess.

That distinction is important. Establishing that a claimant could also have identified or avoided a risk does not itself determine the appropriate reduction for contributory negligence. It remains necessary to consider the standard applicable to each party, their respective expertise, the responsibilities each assumed, and the relative importance of their conduct in causing the loss.

Nor does the engagement of a specialist relieve a claimant of responsibility for his or her own conduct. The 40% allocation against the plaintiffs remained substantial and reflected the pilot’s own responsibilities and his certification that he had carried out the daily inspection.

Key takeaways

• Performing the same task and failing to identify the same risk does not necessarily mean equal responsibility for the resulting loss.
• Contributory negligence requires consideration of both relative culpability and the causal importance of the parties' conduct.
• Different standards may apply to parties performing the same task where their skills, training and expertise differ.
• A professional's contractual responsibilities may be relevant when comparing responsibility.
• Engaging a specialist does not relieve a claimant of responsibility for its own conduct.
• For insurers, the case highlights the importance of assessing the likely extent of contributory negligence, not merely whether the defence is available.

How Clyde & Co can assist

Clyde & Co acts for insurers and their insureds in defending professional negligence and other liability claims across a broad range of industries. We regularly advise on issues of contributory negligence, proportionate liability and the allocation of responsibility between professionals, contractors and claimants. Our experience enables us to assist insurers and insureds in assessing these issues at an early stage and developing an appropriate strategy for the defence and resolution of claims.