In response to a fatal Robinson R22 helicopter accident and a number of other occurrences involving failure of Robinson R22 helicopter V-belts, the ATSB has commenced a safety issues investigation regarding the reliability of the Robinson Helicopter Co. model R22 drive belt system.

Update

Since the commencement of this investigation, the ATSB has examined accidents, incidents and occurrences involving Robinson R22 drive belt (V-belt) failures. Stemming from that, no significant safety issues have been identified to date in the manufacture or design of the drive belts that might present an airworthiness issue for continued safe operation of the Robinson R22 helicopter fleet.

Industry feedback indicates that failures have been relatively infrequent since Robinson introduced the 'Revision-Z' drive belt standard. Once the initial break-in period is complete, the final stability of the belt system is reported to be much better than has been the case with earlier revision belts. The 'Revision-Y' belts were prone to stretch that required periodic adjustment of the drive system throughout the life of the belts.

Although no singular issue has been identified with the drive belt construction, it should be recognised that the belts represent a critical link in the main rotor drive system. Belt failures are often rapid and may be preceded by the onset of vibration or the smell of burning rubber. The ATSB reinforces the need for continued vigilance by operators and maintenance organisations during the routine inspection of the R22 drive system. Some of the factors that can influence the reliability of the R22 drive system are:

Regular inspection: It is an Australian regulatory requirement that the daily inspection of the drive belts and sheaves must be performed by a licensed aircraft maintenance engineer, a pilot endorsed on the aircraft type or an approved person, in accordance with the R22 Aircraft Flight Manual. The ATSB advises that particular vigilance should be applied during these inspections as they represent a fundamental opportunity to detect the onset of deterioration of the drive system. Any form of drive belt damage such as blistering, cracking and tie band (webbing) separation indicates that the belts require replacement.

Robinson Service Bulletin SB-66 highlights the importance of inspecting the sheaves. If the wear pattern is noticeably different from groove to groove, it is recommended that the drive belts be immediately replaced. The surface condition of the sheaves should be smooth and uniform.

Another prime inspection opportunity exists prior to installation of the belts. Careful inspection of the drive belts at this time may identify any surface abnormalities.

Operation: Pilots must monitor Manifold Air Pressure (MAP) to avoid exceeding the placarded power limits, as listed in the Robinson R22 flight manual. Exceeding the drive system limitations may result in sudden belt failure. Refer to Robinson Safety Notice SN-37.

Environment: Operating the helicopter in environments where dust and grit can contaminate the drive system, or where the ambient temperature is high, can also influence the service life of the belts and sheaves. Helicopters operated in these environments may require additional periodic inspections of the drive system.

Sheave alignment: Correct sheave alignment after installation of the drive belts is critical in ensuring the belt longevity.

High gross weight operation: Pilots must ensure that the approved gross weight limits are not exceeded while operating the helicopter.

Clutch actuator: The electrically-driven clutch actuator automatically controls drive belt tension. A cockpit caution light will illuminate when the actuator is re-tensioning, engaging or disengaging the belts. Robinson Safety Notice SN-33 suggests that a problem with the drive belts may be imminent if during flight the clutch light flickers or stays on for longer than normal. Under these circumstances the pilot is advised to land immediately.

ATSB Safety Advisory Notice AO-2011-060-SAN-001

On 6 July 2011, a fatal Robinson R22 accident (AO-2011-060) occurred near Julia Creek, Queensland. The ATSB found that the helicopter sustained an in-flight failure of the drive belts and in the interests of transport safety, issued a Safety Advisory Notice that urged pilots, operators and maintainers to pay particular vigilance to the R22 helicopter drive belt system.

This information is released in accordance with subsection 25(2) of Part 4 of the Transport Safety Investigation Act 2003.

Following a number of accidents and serious incidents involving Piper Chieftain PA-31-350 aircraft where a failure of one of the engine turbochargers had been central to the occurrence events, the Australian Transport Safety Bureau (ATSB) initiated a safety investigation into the broader issue of PA-31-350 turbocharger operational reliability.

In all of the principal occurrences, the turbocharger turbine wheel had separated from its central shaft.  Metallurgical examination of the separated turbine wheel assemblies did not reveal any material/manufacturing anomalies that may have contributed to the failures.

During the course of the investigation, a number of other turbocharger related occurrences were identified. Most of the occurrences had resulted in a reduction in engine power which led to a range of outcomes, including engine shutdown, air returns, and diversions.

While in some occurrences, failure was the result of the separation of the turbine wheel from the turbine shaft, the investigation showed that turbocharger failure could arise from a number of causes, including lubrication issues and foreign object damage. It is likely that some of these mechanisms are interrelated, i.e. fatigue failure of the turbocharger shaft following bearing damage from an interruption or contamination of the oil supply.

No single contributory factor or common set of factors was identified across the failures examined.

Published literature has shown that turbocharger reliability can be significantly enhanced by ensuring that engine, aircraft and turbocharger manufacturer's operational procedures are closely followed - particularly in respect of the application and/or reduction of engine power levels. Specific maintenance attention to the turbocharger lubrication system is also important to ensure preservation and reliable operation of the turbocharger bearings.

Pilots of aircraft powered by turbocharged powerplants are reminded that a failure of the turbocharger system should not result in the complete loss of power from the affected engine. Attention is drawn to a US Federal Aviation Administration, Special Airworthiness Information Bulletin (SAIB) CE-09-11, which provides information for air crew on what to do in the event of a turbocharger malfunction or failure. A copy of that bulletin is included as Appendix B to this report.

Executive summary

Shortly before 0540 on 28 September 2009, a fire started in the steering gear compartment of the Marshall Islands registered anchor handling tug supply vessel Petra Frontier while it was en route from the Timor Sea to Darwin, Northern Territory.

The ship's crew were unable to extinguish the fire using portable fire extinguishers. By about 0640, all of the compartment's access doors and vents were closed, the electrical power supply to the machinery in the space was isolated and the deck above was boundary cooled. As a result of these actions, the fire eventually burnt itself out.

The investigation found that the fire probably started when rags, which had been soaked in oil that was leaking from a hydraulic unit, were ignited by heat generated by, or a spark emanating from, an electrical solenoid. The investigation also found that the ship's crew had not identified the numerous deficiencies that existed in the ship's emergency equipment, they were not familiar with the use of the emergency equipment and the on board response to the fire was not well managed.

The investigation identified two safety issues: while Petra Frontier had undergone a series of flag State inspections and class surveys, neither authority was aware that the ship was unseaworthy in relation to critical safety equipment; and the ship's safety management system contained some contradictory information relating to the scheduling of fire and abandon ship drills.

Preliminary report released 30 October 2009

At about 1130 Western Standard Time on 3 October 2009, the pilot of an Air Tractor Inc. AT-502 aircraft, registered VH-ODP, took off from a paddock on a property about 5 km north-east of Wickepin, WA to conduct agricultural spraying operations. A short time later, the owner of the property discovered the wreckage of the aircraft, which had impacted the ground in an inverted attitude, fatally injuring the pilot. There were no witnesses to the accident.

On 25 September 2008, the pilot of a Bell 206L4 helicopter, registered P2-HBC, was conducting sling loading operations in the vicinity of Lake Murray, Papua New Guinea. While conducting a vertical lift, a witness reported hearing a 'different noise' from the helicopter's engine, before observing the pilot jettison the load. The witness then observed the helicopter oscillating from side to side, yawing to the left and then descending through the tree canopy to impact the ground. The pilot was fatally injured and the helicopter seriously damaged.

This accident is being investigated by the Papua New Guinea Accident Investigation Commission (AIC) in accordance with its obligations under Annex 13 to the Convention on International Civil Aviation. The AIC requested the Australian Transport Safety Bureau's (ATSB's) assistance with their investigation by providing forensic engineering examination of a small selection of instruments and some fuel system detritus recovered from the accident helicopter.

The ATSB subsequently received and examined a fuel quantity gauge, turbine outlet temperature (TOT) gauge and an annunciator panel from the helicopter's instrument cluster. Various marks and observations evident on the components were documented and analysed with respect to the possible relevance of those markings to the accident event. In addition, a small sample of dried material from the internal surfaces of the fuel filter check valve that was provided by the AIC was examined and found to be characteristic of the biopolymer films produced by microbial growth.

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Released in accordance with section 25 of the Transport Safety Investigation Act 2003.

On 9 July 2009, the Transport Accident Investigation Commission (TAIC) of New Zealand requested assistance from the Australian Transport Safety Bureau (ATSB) in the transfer of cockpit voice recorder (CVR) and flight data recorder (FDR) magnetic tape recordings onto  digital media. The transfer was requested to ensure the archival preservation of information obtained during the TAIC's investigation of various accident and incident events.

To protect the information contained on the recordings against unauthorised disclosure, the ATSB performed the work under the provisions of an investigation initiated under the Australian Transport Safety Investigation Act (2003).

On completion of data transfer, the magnetic tapes were returned to the TAIC, together with the digital copies and a technical report outlining the process undertaken. 

Contact details for the TAIC can be found on the web at: www.taic.org.nz

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Released in accordance with section 25 of the Transport Safety Investigation Act 2003.

During a flight on 21 June 2009, a Gippsland Aeronautics GA-8 Airvan aircraft, registered VH-BFS, sustained a fracture of the right main landing gear axle assembly, resulting in separation and loss of the wheel and brake calliper. To assist their investigation of the occurrence, the Civil Aviation Safety Authority (CASA) requested the assistance of the Australian Transport Safety Bureau (ATSB) in the metallurgical examination of the fractured landing gear leg. While the examination provided some information on the nature and location of the failure, the amount of material abraded and lost from the fracture surface (as a result of landing on the fractured leg), precluded a full determination of the fracture mechanism.

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Released in accordance with section 25 of the Transport Safety Investigation Act 2003.

On 5 August 2009, an Airborne Edge Trike microlight aircraft was being operated as sports aviation from the owners private airstrip. The aircraft departed from the private airstrip for a planned flight approximately 10 nm to the north. When the aircraft did not arrive at its destination, a search was initiated by friends. The aircraft wreckage was located approximately 0.65 nm from the threshold of the airstrip. The pilot, who was the sole occupant of the aircraft, was fatally injured.

In assisting the Victorian Police in their investigation of this accident, Recreational Aviation Australia Inc (RA-Aus) requested assistance from the Australian Transport Safety Bureau (ATSB) in the recovery of information from a portable Global Positioning System (GPS) unit recovered from the accident site. To protect the information supplied by RA-Aus to the ATSB and investigative work undertaken to assist RA-Aus, the ATSB initiated an investigation under the Transport Safety Investigation Act 2003 (TSI Act).

The ATSB completed its recovery of data from the Garmin® GPS V portable GPS receiver (serial No: 7304194) and provided the data to RA-Aus in the interests of transport safety, under the provisions of section 61 of the TSI Act.

Contact details for RA-Aus are at website: www.raa.asn.au

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Released in accordance with section 25 of the Transport Safety Investigation Act 2003.

The ATSB has completed its technical analysis report of the flight recorder data from Fairchild Dornier 328-110, registered PK-TXN, on behalf of the Indonesian National Transportation Safety Committee. The aircraft was operating a flight from Jayapura to Tanah Merah, Indonesia when it was involved in a runway excursion on landing.

The National Transportation Safety Committee (NTSC) of Indonesia is responsible for investigating this occurrence. The NTSC requested assistance from the Australian Transport Safety Bureau (ATSB) in the recovery and analysis of information from the flight data recorder. In accordance with clause 5.23 of Annex 13 to the Convention on International Civil Aviation, the ATSB appointed an Accredited Representative to assist the NTSC and initiated an investigation under the Transport Safety Investigation Act 2003.

The ATSB's Technical Analysis Report has been sent to the NTSC to assist its ongoing investigation. The NTSC is responsible for releasing a final investigation report regarding this occurrence.

National Transportation Safety Committee 
Ministry Of Transportation Republic Of Indonesia 
Transportation Building 3^rd Floor
Jalan Medan Merdeka Timur No. 5
Jakarta Pusat 10110
Indonesia

Phone  :  +62 21 384 7601
Email    :  knkt@dephub.go.id

Website: http://knkt.dephub.go.id/knkt/ntsc_home/ntsc.htm

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Released in accordance with section 25 of the Transport Safety Investigation Act 2003.

This supplementary report replaces Section 4.7 (Lost) and some conclusions and safety actions recorded in the ATSB Transport Safety Investigation Report No. 222: Independent investigation into the loss of the Department of Immigration and Multicultural and Indigenous Affairs vessel, Malu Sara, in Torres Strait, Queensland, Australia, 15 October 2005, which was released on 19 May 2006. This supplementary report has been published following the release, and subsequent analysis, of significant new information that was provider to the Coroner during the coronial inquest into the loss of Malu Sara and its five occupants on 15 October 2005 and which related to the initial search and rescue response.

This supplementary report should be read in conjunction with the original ATSB report: Loss of the DIMA vessel Malu Sara in Torres Strait Queensland

This report may contain times that differ from those associated with the same occurrence in the original ATSB report. This is the result of the evidence provided to the coronial inquest.

This report identifies the following safety issues: the lack of follow-up and reporting procedures for immigration response vessels which were not engaged on patrol activities in the Torres Strait; the lack of procedures dealing with an immigration vessel which was overdue at its destination or reported being lost; the absence of training for immigration staff in the reporting and follow-up procedures and general search and rescue overview training; search and rescue coordination responsibility for small Commonwealth vessels; and post search and rescue incident analysis practices.

This report acknowledges the actions taken by the Department of Immigration and Citizenship and the Australian Maritime Safety Authority to address the identified safety issues.