In McDermott & Ors v Robinson Helicopter Company Incorporated1, the Queensland Court of Appeal has recently found liability against a helicopter manufacturer for failing to provide instructions for an adequate system of inspection and maintenance in its helicopter maintenance manual.  Importantly, the decision illustrates that where the consequences of a product failing will be of high severity, there is a heavy onus upon the manufacturer to identify the risk and provide instructions to reduce or eliminate it, even where the probability of the risk materialising may be small.

In particular, the content and language of the product manual’s instructions can be critical in terms of providing reliable maintenance and operation methods, appropriate instructions to avoid the risk of the product failing, and appropriate instructions to avoid the risk that the maintenance methods provided in the manual may not be failsafe.


In 2004, a Robinson 22 helicopter crashed whilst being used to check fencelines on a cattle property.  The crash resulted in the death of the pilot and injuries to the sole passenger.  The sole passenger, his spouse and his employer claimed against several defendants, however only the claims against the manufacturer proceeded to trial.  


The cause of the crash was agreed to be a loose bolt (‘Bolt 4’) in the forward flexplate of the helicopter, a critical part by which power is transferred from the engine to the helicopter blades.  The looseness of the bolt caused fretting on the surface on the bolthole in the flexplate, which in turn caused two cracks to develop, which eventually resulted in a piece of the flexplate coming away.  As a result of the broken flexplate, the control of the helicopter was lost.


The manual provided that the servicing Licensed Aircraft Maintenance Engineer (LAME) ‘should’ inspect the condition of the flexplate and “verify the security of the bolts”, including inspection for signs of looseness and correct installation.  That inspection focused upon checking “torque stripes”, being stripes that should be painted across the bolt and nut and extend to the part being fastened.  In theory, if the bolt was loose, the torque stripe would break upon rotation of the bolt and provide an indication that action needed to be taken to rectify the looseness. 


The weight of the evidence was that the torque stripes were not reliable to detect defects.  Evidence given by the LAMEs who actually inspected the helicopter and other experts indicated that the torque stripe may not be applied at the time of installation, may not be applied correctly, and may deteriorate in such a way that it did not indicate movement of the bolt.  

The inspecting LAMEs gave uncontested evidence that in conducting their inspections, they did not observe that the torque stripes indicated any cause for concern as to the security of the bolt.  While one of the LAMEs conceded that when working under pressure he may miss a “telltale sign of a loose bolt” this was accepted as merely an acknowledgement of human fallibility and not evidence that he had in fact missed an indication of a loose bolt.

The Court of Appeal held it was not open to the Court to make findings that the LAMEs had overlooked a missed or broken torque strip as these scenarios had never been put to the LAMEs when they gave evidence.  Pursuant to the principle in Brown v Dunn2, the Court could not rely on propositions contradictory to the testimony of the LAMEs when the LAMEs had not been given the opportunity to respond to the propositions.

The Court held that in the absence of any basis for finding that the inspection or maintenance performed by the LAMEs was negligent, the manual’s instructions for reliance upon the torque stripes as a method for verifying the security of the bolt was inadequate.


While the instruction manual did specify that the security of the bolts should be verified and provided a method for doing so, it was not enough.  The maintenance method specified was not reliable, and the manual did not provide a warning or instructions accounting for the risk that the method may fail.  Further, the language used in the instructions may have been inadequate, as the instructions for the application of the torque stripe were that it “should” extend to all parts of the bolt, nut and parts being fastened rather than “must” extend (as is necessary for the indication of bolt rotation).


This decision underlines the need for manufacturers to take great care when producing manuals for the operation and maintenance of products, particularly where those products are inherently dangerous.  The greater the severity of the consequences of failure, the greater the onus is upon manufacturers to provide manuals identifying the risks and providing instructions on how those risks can be reduced, if not eliminated.

Manufacturers will not escape liability simply by providing a manual that gives instructions for a qualified and competent person to carry out specific maintenance protocols if those protocols will not provide a reliable safeguard against failure.    

As far as possible, manufacturers should ensure maintenance manuals:

a)contain failsafe maintenance and operation instructions (or as close thereto as possible);

b)provide instructions for addressing the risk that manual’s instructions may not be failsafe (such as implementing appropriate redundancies in protocols); and

c)use appropriate language conveying the necessity of actions that are required for the proper maintenance and use of the product.

To access a copy of this decision, please click here