At about 1207 on 21 March 2013, a Robinson Helicopter Company R44 helicopter (R44), registered VH-HWQ, landed at a grassed area adjacent to a function centre at Bulli Tops, New South Wales. Shortly after landing, the helicopter was observed to simultaneously lift off, yaw right through 180° and drift towards nearby trees. The helicopter struck branches of the trees before descending, impacting the ground nose low and rolling onto its right side. A short time after coming to rest a fire started and engulfed the helicopter. The pilot and three passengers were fatally injured.
What the ATSB found
The circumstances of this accident were consistent with the helicopter lifting off following a deliberate or inadvertent collective input. The helicopter’s main rotor blades subsequently contacted nearby trees resulting in a loss of control and impact with the ground. The impact sequence resulted in a substantial fuel leak that was followed by an intense fire. This accident was similar to two other relatively recent fatal accidents in Australia involving R44s fitted with all-aluminium fuel tanks in which there was a fatal post-impact fire (PIF) following an otherwise survivable impact. Statistical analysis of helicopter accidents that occurred in Australia and the United States (US) between 1993 and 2013 identified a significantly higher proportion of PIF involving R44s than for other similar helicopter types. That analysis also identified that, despite the introduction of requirements for newly certificated helicopters to have an improved crash-resistant fuel system (CRFS) some 20 years previously, several helicopter types were still being manufactured without a CRFS and that many of the existing civil helicopter fleet were similarly not fitted with a CRFS.
What's been done as a result
Following this accident the Civil Aviation Safety Authority (CASA) took action to increase compliance with the helicopter manufacturer’s Service Bulletin 78B (SB-78B), requiring the fitment of bladder-type fuel tanks and other fuel system improvements. While recognising the action taken by CASA, due to concern that a significant number of Australian owners and operators had at that stage not taken steps to comply with the service bulletin, and were very unlikely to be able to do so by the required date of 30 April 2013, the ATSB released safety recommendation AO-2013-055-SR-001 to CASA that further action be taken. In response CASA released airworthiness directive AD/R44/23 requiring all owners of R44 helicopters in Australia to comply with SB-78B by the required date. Several other national airworthiness authorities (the South African Civil Aviation Authority, the Civil Aviation Authority of New Zealand and the European Aviation Safety Agency) subsequently mandated compliance with SB-78B. At the time of publishing this report the State of Design and Manufacture of the R44 helicopter had not mandated compliance with SB-78B.
The ATSB has issued a safety recommendation to the US Federal Aviation Administration (FAA) that they take action to ensure all R44 operators and owners comply with the manufacturer's Service Bulletin SB-78B and fit bladder-type tanks to improve resistance to post-impact fuel leaks. In addition, the ATSB also recommend that the FAA and European Aviation Safety Agency take action to increase the number of existing and newly-manufactured helicopters that are fitted with a crash-resistant fuel system.
This accident highlights the catastrophic consequences of fuel-fed post-impact fire and that the most effective defence is to prevent the fire from occurring at impact by containing the fuel on board, preventing ignition, or both. In that context, the ATSB strongly encourages the fitment of a crash-resistant fuel system where possible.