On 1 November 2006 at 1201 Eastern Standard Time, the pilot of a Cessna Aircraft Company 207, registered VH-UBX, was on final approach to runway 07 at Townsville Airport, when the engine stopped. The pilot attempted to restart the engine but was unsuccessful. To avoid the airport perimeter fence, the pilot elected to conduct a forced landing into an adjacent tidal swamp. The pilot landed the aircraft in the swamp and the aircraft sustained major damage. The pilot and three passengers were uninjured.

An inspection of the aircraft revealed that there was adequate fuel on board to complete the flight. Further investigation found several mechanical problems with the engine-driven fuel pump that were associated with foreign object debris and errors in maintenance.

The investigation identified safety issues with a third-party maintenance provider's procedures and the operator's in-flight engine restart procedures.
As a result of this accident, the third-party maintenance provider has made changes to its operation and recalled a number of pumps that were subject to unauthorised maintenance.

On 4 October 2006, at approximately 1045 EST, while on a scheduled flight from Canberra, ACT to Sydney, NSW, a Bombardier de Havilland DHC-8-315 (Dash 8) aircraft, registered VH-TQY, experienced a hydraulic system failure while on approach to land at Sydney Airport.

The flight crew became aware of the system failure when they selected the landing gear to extend during the approach sequence. Shortly after, the low oil pressure caution light for the number 2 hydraulic engine pump illuminated. The crew established that the nose and right main landing gear doors had remained open, and the left gear door had closed after all the gears had been extended.

The flight crew issued a radio alert to air traffic services and the aircraft commenced a missed approach. The crew then carried out the relevant quick-reference handbook (QRH) checks and landed at Sydney Airport on runway 16L without further incident.

The investigation determined that a solenoid-sequence valve failed, which resulted in the loss of pressure and quantity of hydraulic fluid from the aircraft's number 2 hydraulic system. Failure of the solenoid-sequence valve was due to the fracture of three of the four bolts that had clamped the two halves of the component together. Each of the fractured bolts had failed due to metal fatigue from exposure to in-service cyclic stresses that had developed during the operation of the aircraft's hydraulic system.

On 23 October 2006, the Air Safety Investigation Branch (ASIB) of Papua New Guinea notified the Australian Transport Safety Bureau (ATSB) of an accident that occurred on 20 October 2006, at 1200 Eastern Daylight-saving Time, involving a Bell Helicopter Co Jetranger helicopter, registered P2-HBG, that was piloted by an Australian citizen. The helicopter was reported missing and was subsequently found to have impacted rough terrain approximately 102 km north of Port Moresby. The pilot and three passengers were fatally injured.

The ATSB initially appointed an expert to the investigation into the accident, in accordance with clause 5.27 of Annex 13 to the Convention on International Civil Aviation.

On 6 November 2006, the ASIB requested ATSB assistance to oversight the examination of the helicopter's engine that was to be conducted at an Australian maintenance facility. To assist in that process, it was agreed that the ATSB could appoint an accredited representative, in accordance with Clause 5.23 of Annex 13 to the Convention on International Civil Aviation, to participate in the ASIB's investigation.

To protect the information supplied by the ASIB to the ATSB and investigative work undertaken to assist the ASIB, the ATSB initiated an investigation under the Transport Safety Investigation Act 2003. Subsequently, the ASIB advised the ATSB that the engine examination would not be conducted in Australia.

On completion of its investigation, the ASIB of Papua New Guinea will publish the final investigation report regarding the accident.

Preliminary report released 20 November 2006

The aircraft wreckage, located in a forest, was destroyed by impact forces and a post-impact fire. The pilot and a passenger were fatally injured.

On 11 October 2006, at approximately 1420 Central Standard Time, a Boeing Co 767-336 was departing from bay 3 at Darwin Airport, NT for Brisbane Airport, Qld. Just prior to taxi, an auxiliary power unit (APU) fire warning activated with associated indications. The crew carried out the APU FIRE checklist items and the APU fire warning message extinguished, and the aural APU fire warning ceased.

Company engineering and Aviation Rescue and Fire Fighting (ARFF) personnel performed an external visual inspection of the APU area and advised the crew that there were no signs of a fire from the APU. The aircraft was returned to the departure gate.

The aircraft was returned to service under the provision of the B767 minimum equipment list item applicable for the operation of the aircraft with an inoperative APU.

During overnight maintenance in Sydney, company engineering staff found the remnants of a significantly charred cloth rag located on top of the aircraft's APU.

A number of safety actions were carried out or proposed by the operator as a result of this incident, including:

• amendments to the maintenance documentation for clearance closure inspections
• action to reinforce the responsibility and importance of the clearance closure inspections and to remind maintenance staff of the company's 'Safety over Schedule' principles
• the review of the suitability of equipment to gain access to all areas of the APU compartment
• a review of relevant licensed aircraft maintenance engineer training.

In addition, as a result of this incident, the ARFF changed its procedures to include that, until an ARFF response was called to a 'STOP', either an aircraft engineer or ARFF member was required to inspect the relevant aircraft compartment or area where a fire had occurred, an aircraft's fire warning system had activated, or an onboard fire extinguisher had been activated.

On 19 October 2006, at about 0635 Eastern Standard Time the crew of a de Havilland Canada DHC 8-200 aircraft, registered VH-TQX, departed from Melbourne Airport, Vic on a scheduled flight to Wollongong NSW. At about 0645, as the aircraft was climbing through flight level 140, the pilot in command (PIC) detected smoke in the aircraft. Soon afterwards a smoke detector warning sounded in the aircraft toilet and the flight and cabin crew observed smoke haze. The flight crew reported the situation to air traffic control (ATC) then diverted the aircraft to Melbourne and carried out the appropriate recall and checklist actions. The aircraft landed in Melbourne on runway 16 at 0658. There were no reported passenger or crew injuries.

The manufacturer's examination of the engine showed that oil had leaked from several compressor bearings into the low-pressure compressor of the engine. The high temperature of the compressed air and the engine components caused the oil to vaporize, contaminating the air extracted from that engine section to the aircraft cabin. The manufacturer had previously issued three service bulletins recommending engine modifications pertinent to this occurrence. Compliance with the bulletins was optional. However, the operator had already modified about 90% of the affected engines in its fleet at the time of the incident. The operator has planned to modify the remaining engines at the next period of scheduled or unscheduled maintenance.

The crew's timely assessment and response to the in-flight emergency reduced the likelihood of an extended exposure to the fumes by the passengers and crew. Also, the initiation of an emergency phase by air traffic control ensured that appropriate services were available to assist the crew after the aircraft had landed.

The engine manufacturer has undertaken to update the Workscope Planning Guide for the PW 123D engine to improve its resistance to internal oil leakage.

On 24 September 2006, during a scheduled passenger service from Darwin, NT, to Denpasar, Indonesia, the left engine of a Boeing Co 737-400 series aircraft sustained a mechanical failure within the first-stage low-pressure turbine (LPT) section. After reducing the engine thrust to minimise vibration and further damage, the flight crew returned the aircraft to Darwin.

Following an analysis overseen by the Australian Transport Safety Bureau, the engine manufacturer found that it was likely that thermally induced microstructural creep damage had contributed to the blade failure and subsequent damage to the turbine stage. An examination of the engine maintenance and operating records did not reveal any instance/s of hot-starting or significant take-off exhaust-gas temperature exceedance that may have contributed to the premature failure.

A total of seven related LPT stage-one failures had been identified by the engine manufacturer, including two from the subject Australian operator. While work by the engine manufacturer to better understand the issue was continuing, a range of stage-1 LPT blade production batches were identified as possibly being predisposed to premature failure. The engine manufacturer has recommended that LPT blades from the identified batches be removed from service and quarantined at the next maintenance opportunity, pending their further investigation and assessment of the issue.

On 19 September 2006, at approximately 1630 Eastern Standard Time, the pilot of a Boeing Stearman, registered N-73410, experienced a control problem while taxiing. The pilot reported that while conducting engine and power checks the aircraft inadvertently became airborne after hitting a bump on the airstrip that coincided with a gust of wind. He decided to continue with the take-off intending to complete a circuit and return the aircraft to the airstrip. The pilot reported that after banking to the left, he lost aileron control and the aircraft impacted the ground, flipped over and came to rest in an inverted position. The passenger received minor injuries and the pilot was uninjured. The aircraft was substantially damaged.

The pilot stated that prior to the accident he had engaged the flight controls lock on the aircraft while it was stationary on the airstrip. He reported that during the taxi runs he discovered that the flight controls lock was still engaged so he unlocked it. He subsequently believes that this action was unsuccessful and was why he was unable to control the aircraft during the take-off.

Five witnesses, who had earlier in the day assisted the pilot to move furniture, reported that they understood from the pilot that if the weather conditions were suitable, three of them would get a flight in the Stearman. The aircraft did not have a current maintenance release and was not airworthy.

The investigation was unable to reconcile the discrepancies between the pilot and witness reports.

The crew of a SAAB SF340B reported that shortly after take-off from Sydney Airport, NSW, they observed a zero reading on the left torque gauge and advised air traffic control that they were returning to land. During the approach, the crew made a PAN broadcast and advised that the left engine had been shut down. After landing the crew reported that they experienced airframe vibration and suspected a tyre had blown on landing. An inspection by emergency services personnel did not find any damage to the tyres and the crew taxied the aircraft to the terminal apron.

An examination of the aircraft systems could not find any reason for the zero reading on the left torque gauge, but the left digital engine control unit was replaced. A review of the crew's actions after they observed the loss of torque indication on the left torque gauge, found that they had selected the 'auto coarsen' switch to ON, prior to landing. That was contrary to directions in the flight crew operations manual that required the switch to be selected OFF when torque gauge indications read zero or were erratic. Consequently, the left propeller blades were automatically coarsened, effectively feathering the left propeller and resulted in an asymmetric landing.

The operator issued a notice to its aircrew reminding them of the requirement in the flight crew operations manual to not select 'auto coarsen' in these circumstances.

On 18 September 2006, at 1417 Eastern Standard Time, a Boeing Co 777-2H6 aircraft, registered 9M-MRM, departed Brisbane Airport, Qld for Kuala Lumpur, Malaysia. The flight crew reported that, at approximately 1422, when the aircraft was 74 kms west-north-west of Brisbane Airport and climbing through 10,300 ft, they felt a 'sudden jerk' followed by an Engine Indication and Crew Alerting System message 'ENG FAIL R'. The crew informed Brisbane Air Traffic Control of the right engine failure and performed the relevant checklist items to successfully restart the right engine.

After dumping fuel to reduce the landing weight, the crew returned the aircraft to Brisbane Airport. The company's ground handling agent's engineering personnel replaced the right engine Fuel Metering Unit (FMU) and the aircraft was returned to service.

The investigation found that there had been a loss of damping fluid in the turbine overspeed servo valve, adversely affecting the operation of the servo valve. As a result, the turbine overspeed servo valve became de-latched, and the engine shut down in flight.

A number of safety actions were carried out as a result of this incident, including by the:

• manufacturer of the turbine overspeed servo valve, who will check the servo valve when the units are returned for overhaul; and
• manufacturer of the FMU, who mandated a check of the torque setting of the turbine overspeed servo valve retaining bolts when the units are returned to their repair bases.

In addition, the engine manufacturer:

• is investigating the feasibility of the development of a test to confirm the serviceability of the turbine overspeed servo valve damping fluid in installed engines; and
• has published non-Mod Service Bulletin NMSB73-F408. That bulletin recommended the on-wing torque inspection of the turbine overspeed servo valve bolts in all installed engines or engines in overhaul shops where the life of the FMU is greater than 5,000 hours.