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New documents involving the ditching of an MRH-90 Taipan helicopter into Jervis Bay last year have been tabled in Parliament.
Deputy Prime Minister and Minister for Defence Richard Marles this week tabled the summary of the safety report into the 2023 Jervis Bay ditching, following a request from Senator Malcolm Roberts.
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The Australian Army MRH-90 Taipan multirole helicopter, Bushman 82, impacted water in the vicinity of Jervis Bay, NSW, during a routine counter-terrorism training exercise on 22 March last year, with all 10 personnel aboard recovered.
Divers were suspended from the aircraft awaiting extraction at the time of the crash and reported that the aircraft experienced catastrophic and contained failure of its number one left-hand engine.
“Upon the crew’s recognition and communication of engine failure indications, the flying pilot began bold-face emergency procedures. The flying pilot moved the aircraft forward slowly as the aircraft descended, with the right-hand engine automatically operating at its maximum available OEI power rating,” the report reads.
“Neither the flying pilot nor non-flying pilot was able to complete the emergency checklist action to manually activate the Emergency Floatation System (EFS). The left-hand aircrewman released the left hand with suspended divers from the aircraft. However, the right-hand aircrewman was not able to complete emergency procedures to release the right hand which resulted in the suspended divers being dragged unexpectedly through the water.
“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 8G.”
The documents confirmed that following the impact, divers were recovered by the on-scene emergency rescue vessels, while the entire crew and divers were transported to HMAS Creswell for immediate medical care.
“The failure of the HP 1 blade, which caused the catastrophic, but contained, engine failure, was the first of this type experienced by an Australian Defence Force (ADF) MRH-90 Taipan RTM-322 engine,” according to investigations outlined in the report.
“However, in 2017, as a result of several HP 1 failures across the global fleet, the original equipment manufacturer (OEM) issued a NH90 Service Bulletin recommending that operators of the RTM-322 engine should (vice being a mandatory requirement) replace HP 1 blades with modified blades.
“Hazard analysis of the OEM’S recommendations was conducted by the Navy and Army Aviation Military Air Operator (MAO) airworthiness and operations enterprise in consultation with the Defence Aviation Safety Authority (DASA).
“They determined that the ‘Design Safety Case’ for the MRH-90’s RTM-322 engine remained within the certification basis albeit with an extremely small increase in the likelihood of engine failures throughout the life-of-type of the MRH-90 fleet of aircraft.
“The Army Aviation MAO decided to modify MRH-90 engines as per the OEM’s recommendations during routine deeper-level maintenance programs. Neither engine installed in MRH-90 A40-025 was modified with new HP 1 blades.
“The non-flying pilot’s perception that the aircraft had settled on the water was likely influenced by a lack of visual cues caused by low illumination and sea spray.
“The non-flying pilot perceived the aircraft would roll inverted and snagging hazards related to the TopOwl Quick Release Pack, and associated helmet leads, would prevent underwater egress from the cockpit. As a result, they decided to remove their helmet and begin emergency egress in accordance with Helicopter Underwater Escape Training (HUET) drills.
“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.
“The investigation identified 13 recommendations for safety improvement, primarily aimed at organisational-level policy, processes, standardisation and training, as well as the efficacy of aviation risk management.”
