Taipan ditching caused by engine failure, pilot error, poor training

An internal Defence report tabled in the Senate has identified a number of pilot mistakes and inadequate training as major contributors to the highly publicised ditching of a twin-engine Taipan helicopter, codenamed Bushman 82, last year.  The accident occurred over water near Nowra during a training exercise on 22 March 2023, with no loss of life – but it was a close-run thing. Defence Minister Richard Marles has chosen to release only the redacted Executive Summary, writing in the covering letter: “Defence has advised me that there is a significant risk that release of the full report and associated documents at this time may influence the willingness of personnel to participate in other investigations, which may impede ongoing investigations into the incident off Lindeman Island on 28 July 2023 by Defence, the Inspector-General of the Australian Defence Force, and other authorities. Defence further advises me that, were this to occur, it would represent a significant legal risk to the Commonwealth.” Investigations into flying accidents usually reveal a complex set of circumstances, and this is no exception.  The root cause of the accident was the rupture of a high-pressure turbine blade in the left-hand side Number 1 engine, which caused a catastrophic but contained failure.  This particular problem has never occurred previously and in fact the engines – and the entire family of NH90 helicopters, of which Taipans are a part – are exceptionally safe. However, in the aftermath of the incident, Army implied that everything was due to this single technical issue.  Consequently, this has been fed to the media – and through them a false narrative has been conveyed to the Australian public that Taipans are unsafe and had to go. The truth is far more complicated than that – and has profound implications for the ongoing inquiry in the fatal Lindeman Island crash, which claimed the lives of four service personnel. In an emergency, Taipans are designed to fly on a single engine – the Safran RTM-322 – which is one of the most safe and reliable in its class.   However, as bad luck would have it the helicopter was at very low altitude and was heavily loaded at the time with Special Forces divers. Because it takes a fraction of a second for the computerised engine control system to respond to a failure, the helicopter dropped while moving slightly forward and briefly touched the sea surface before rising to a low hover. So far, so good – the helicopter responded as it should – but an already scary situation was made worse because four Special Forces divers were hanging onto the outside of Bushman 82 as part of the exercise.  From here on, the situation gets even messier, with the report stating that aircrew in the back of the helicopter were able to release the two SF divers on the left-hand side – who dropped safely into Jervis Bay – but the two on the right-hand side were dragged unexpectedly through the water, being stripped of their equipment in the process. The crucial part of the report then explains: “Bushman 82’s aircrew did not recognise the aircraft briefly impacted with water while executing initial bold-face emergency procedures. With the Automatic Flight Control System ‘Hover Mode’ still engaged and the right-hand engine at maximum power, the aircraft then rose into a low hover of approximately 23 feet albeit with rotor speed decaying. “The Non-Flying Pilot in the left-hand cockpit seat, believing the aircraft had settled on the water, removed their helmet in preparation for commencing emergency egress procedures. The Flying Pilot in the right-hand cockpit seat, now aware the aircraft was in fact in a low hover, shut down the right-hand engine at a height of approximately 19 feet. This resulted in a high rate of descent, an impact force of 80, extensive structural damage to the airframe and automatic activation of the EFS (Emergency Floatation System.” An earlier part of the report states and is worth repeating: “As a result of the Flying Pilot’s actions to shut down the Number 2 (right-hand) engine at a height of approximately 20 feet, the aircraft descended rapidly and impacted the water a second time at a force of 8G. The crew egressed successfully with minor injuries and were retrieved by prepositioned emergency rescue vessels.” This has been the consistent reporting of APDR – the helicopter performed as designed, but the situation could have involved serious loss of life because of human operator error.  Hitting the water at 8Gs is no joke and one shudders to think what would have happened to all on board if they had been on another type of aircraft. The report also says that the Army had decided for reasons of cost not to implement a fix for the RTM-322 engine turbine blades that had been recommended years before by the manufacturer. In dry language, the report details the confusion in the cockpit about the altitude of the Taipan – and because of this misperception first one pilot and then the second, removed all connections to their Top Owl day/night helmet so they could get out as quickly as possible.  This was motivated by an unjustified fear that the helicopter – which is fitted with safety flotation devices – would quickly roll over and sink. This misperception might have been caused because that is what would have happened if a helicopter without floatation devices – such as a Black Hawk or a Sea Hawk – had been forced to ditch in similar circumstances. The report continues: “The Non-Flying Pilot’s decision to remove their helmet contributed to the lack of effective crew coordination and communication to complete emergency checklist procedures to ditch the aircraft and prepare for the crew’s egress. In particular, selection and operation of switches by the pilots for critical systems, such as aircraft engines, requires the pilots to communicate to identify the selection and confirmation of the correct operating system. Therefore, when the Non-Flying Pilot removed their helmet, they were less likely to be able to prevent the Flying Pilot’s inadvertent or inappropriate selection of the right-hand engine STOP-IDLE-FLIGHT switch to STOP. “The Flying Pilot’s decision to shut down the right-hand engine was not in accordance with standard emergency procedures. This decision was found to be heavily influenced by their concern over potential injuries to the crew and personnel in the vicinity caused by flying debris from high-energy rotors striking the water. The Flying Pilot’s awareness and level of concern was formed after witnessing injuries to personnel in similar circumstances during a rotary-wing accident while serving on an overseas exchange posting.” To stress the point that APDR has repeatedly made, the Taipans are a very safe platform and have a better record than any other contemporary helicopter.  Because the Nowra ditching occurred four months prior to the Lindeman Island fatality, much of the incorrect commentary – encouraged by Army – has allowed an impression to build up that the helicopters were unsafe. Nothing could be further from the truth – and the real culprit looks to be Army and their processes, particularly training.  The end result of this unfortunate chain of events is the completely unnecessary scrapping of the entire Taipan fleet.  The exact causes of the Lindeman Island tragedy await the outcome of a separate inquiry, expected to be finalised by the end of this year. It is also worth noting that this report was finalised a year ago. For Editorial Inquiries Contact : Editor Kym Bergmann at [email protected] For Advertising Inquiries Contact: Group Sales Director Simon Hadfield at [email protected]