Shortly after departing Jandakot, WA the flight nurse advised the pilot that she had detected a burning odour in the aircraft's cabin. The pilot also noticed the odour a short time later. There was no smoke and no visible sign of fire. Due to the unidentified nature of the odour, the pilot initiated a diversion back to the departure aerodrome and donned his emergency oxygen equipment. The pilot also turned the under floor auxiliary heating system OFF.

Early during the diversion to Jandakot, the flight nurse reported to the pilot that the odour seemed to have dissipated. The flight landed safely at Jandakot with no further report of any fumes in the cabin.

A maintenance investigation by the operator was unable to positively identify the source of the burning odour, or indication of burning.

The cessation of the burning odour shortly after the pilot turned the under floor auxiliary heating system OFF could have been consistent with an amount of accumulated dust deposit dislodging from the heater supply duct for the passenger compartment's auxiliary heating system and coming into contact with its heating element.

The decision by the pilot to immediately don his oxygen mask minimised his exposure to any fumes that might have been associated with the burning odour. That action minimised the risk of any potential toxic or incapacitating effect on the pilot's subsequent performance.

At 0938 Central Standard Time on 2 August 2006, a Boeing Company 717-200 aircraft, registered VH-NXE, took off from Alice Springs Airport, NT, on a scheduled flight to Perth, WA.

The applicable aircraft take-off settings and techniques were applied by the flight crew for the takeoff. The recorded data showed that, 4 seconds after lift off, when about 31 ft above the runway, the aircraft's stall warning system activated for 4 seconds, and that the aircraft did not approach an aerodynamic stall condition at any time during the stick shaker activation. In response to the activation of the stick shaker, the flight crew increased engine thrust and reduced the aircraft's pitch attitude.

It is almost certain that an incorrect left wing slat sensor signal was received by the proximity sensing electronics unit (PSEU) from one of the two left wing slats proximity sensors. Consequently, the different slat position signals from the two sensors in the left wing resulted in the PSEU defaulting to the slats not-extended indication for the left wing. As a result of the different slat position signals sent by the proximity sensing electronics unit for the left wing (slats not-extended) and right wing (slats extended), the aircraft's flight control computers used the flaps-extended/slats-retracted stick shaker angle of attack schedule, leading to stick shaker activation and other stall indications.

Although no explanation could be found for the incorrect signal received by the PSEU from one of the two left wing slats proximity sensors, the aircraft manufacturer concluded that there did not appear to be a systemic problem in the worldwide 717 fleet.

On 8 August 2006 at 1115 EST, a Cessna Aircraft Company model 182P aircraft, registered VH-WNR, departed Archerfield Aerodrome, Qld, on a private flight to Goondiwindi, Qld. The pilot was the only person on board. At 1121, the pilot transmitted a distress message to air traffic control that he was attempting an emergency landing, and that the aircraft engine had failed. At that time, the aircraft was approximately 5 km west of Archerfield Aerodrome at about 1,000 ft above ground level. The aircraft subsequently collided with powerlines before impacting the roof of a house. It traversed the roof and came to rest inverted a short distance from the rear of the house. A fire began when leaking fuel ignited. The pilot received serious burns to his upper body. The aircraft was destroyed by impact forces and fire. The house sustained major structural damage to its roof and two of the three occupants received minor injuries.

Subsequent engine disassembly and examination revealed catastrophic damage to the engine related to the failure of the number 5 cylinder connecting rod assembly. Reduced connecting rod pre-load, due either to insufficient assembly torque, or excessive torque producing permanent bolt stretch, was considered the most likely reason for the failure of the connecting rod assembly. However, because of the consequential damage caused by continued engine operation, there was inadequate evidence to directly support either failure mode.

On 29 July 2006 at approximately 0917 Eastern Standard Time, an Airbus A320-232 (A320) aircraft, operating under the instrument flight rules (IFR), was on a scheduled passenger service from Sydney, NSW, to Hamilton Island, Qld. The crew was conducting a runway 14 very high frequency omni-directional radio range (VOR) instrument approach to land at Hamilton Island Airport. At that time, a de Havilland Aircraft Pty Ltd DH-82A Tiger Moth (Tiger Moth) aircraft, operating under the visual flight rules (VFR), was seen to be near the A320's approach path to the north-west of Hamilton Island. The pilot of the Tiger Moth had not complied with a previous instruction to remain east of the eastern tip of Hamilton Island, which was well to the east of the instrument approach path.

The Hamilton Island aerodrome controller (ADC) issued clearances and instructions to the pilot of the Tiger Moth and to the pilot of the A320 to facilitate traffic management in accordance with published procedures. He was not required to apply a separation standard between an aircraft operating under the IFR and another aircraft operating under the VFR in class D airspace. He was required to provide traffic information to the pilots of both aircraft in class D airspace.

However, the aerodrome controller did not provide traffic information to the pilots of either aircraft in accordance with class D procedures. The pilot of the Tiger Moth did not comply with the air traffic control instructions. The provision of traffic information may have assisted the pilot of the Tiger Moth with situational awareness and helped to ensure that he did not proceed towards the A320 as it approached Hamilton Island.

On 23 June 2006 at about 1730 Eastern Standard Time, a Beech Aircraft Corp 58 (Baron) was conducting a global positioning system (GPS) arrival procedure for arrival at Orange Aerodrome, NSW. The aircraft was approaching the aerodrome from the west. At the same time, a SAAB Aircraft AB SF-340B (SAAB) was conducting an Orange runway 29 straight-in area navigation global navigation satellite system (RNAV GNSS) approach. The two aircraft had the same estimated time of arrival at Orange Aerodrome. They were both being operated under the instrument flight rules and were in instrument meteorological conditions.

At the missed approach point of the GPS arrival procedure, and at an altitude of 4,220 ft, the pilot of the Baron had not become visual with the aerodrome. He commenced the published missed approach procedure and made a transmission on the Orange common traffic advisory frequency (CTAF) to advise local traffic that he was conducting that procedure. That required the pilot to track a bearing of 098 degrees magnetic from the Orange non-directional beacon and to climb the Baron to the minimum sector altitude of 5,200 ft above mean sea level.

The captain of the SAAB advised the pilot of the Baron that, in order to maintain separation, the pilot of the Baron would have to manoeuvre his aircraft. The pilot of the Baron manoeuvred his aircraft accordingly.

On 22 July 2006, at 1615 Eastern Standard Time, a de Havilland Canada Dash 8 aircraft, registered VH-TQR, departed Canberra Airport. Late in the take-off roll, the left ENGINE MANUAL caution light illuminated, and the take-off was continued. At approximately 2,500 feet above mean sea level, the crew noticed that the left engine torque gauge indicated 108 % torque and, soon after, the left engine propeller feathered. The departure was continued and the flight crew carried out the required check list items, shut-down the left engine and returned the aircraft to Canberra.

The operator's engineering personnel replaced the left engine hydromechanical fuel control unit, electronic control unit and propeller assembly and the aircraft returned to service.

A preliminary investigation into a category 4 occurrence that occurred at Sydney Aerodrome on 29 June 2006, which involved a reduction in the required visual separation standard between a departing Boeing Aircraft Company 737 (B737) aircraft and an arriving Robinson Helicopter Company R44 (R44) helicopter, determined that the pilot of the R44 had sight of the B737 at all times, and that there was no risk of a collision between the B737 and the R44.

The inadvertent reduction in the required visual separation standard was as a result of the pilot in command of the R44 misjudging the acceleration of the B737 during its take-off roll. The likely safety outcomes of continued investigation did not warrant further allocation of resources.

Status: Downgraded the occurrence to category 5 and investigation discontinued.

On 29 June 2006, Bombardier DHC-8-402 (Dash 8-400) was being operated on a scheduled passenger service from Brisbane to Mackay, Qld. As the aircraft passed through FL220, the cabin altitude warning light illuminated, accompanied by the associated aural warning.

Initial checks by the crew indicated that the cabin differential pressure and cabin air flow appeared to be normal. The aircraft's bleed air switches also appeared to the crew to be correctly selected to the ON position.

An attempt by the crew to manually confirm the position of the bleed air switches revealed that both switches were in the OFF position. The subsequent selection of the switches to the ON position extinguished the cabin altitude warning light and the associated indications, and the aircraft's pressurisation system commenced normal operation.

In response to this incident, the operator developed an amendment to the Flight Crew Operating Manual for application in the company's turboprop operation, including affecting the Dash 8-400 checklist. The amendments to the aircraft checklist included:

• revised responses to the pressurisation-related checklist items
• an additional Pressurisation checklist requirement to be conducted at Transition
• the addition of the requirement for the tactile confirmation of some checklist responses, including when one pilot has responsibility for both the 'challenge' and 'response' actions.

Between 2001 and 2006, there were a number of fatal single and multi-engine aeroplane accidents that occurred, where the ATSB found that engine power loss during or after takeoff preceded loss of control. Those accidents involved different aircraft types, all below 5,700 kg MTOW, and a variety of pilot experience. Partial power loss, sometimes intermittent, featured in most of the single engine power loss accidents. ATSB research papers were also indicating an uncontrolled flight into terrain (UFIT) problem. 

While the ATSB investigated each accident individually, a safety issue investigation was initiated on 3 July 2006, to enable a broader look into what may assist the aviation industry to manage the risk of operating aircraft that don't have assured takeoff performance when an engine loses power (generally aircraft below 5,700 kg MTOW). Of particular interest was how pilots managed a partial engine power loss during or soon after takeoff in single engine aircraft.  

The investigation found no significant safety issues that had not been addressed by developments and changes within the aviation industry since July 2006. As a result, the safety issues investigation was discontinued, however the ATSB has initiated an aviation research project to produce educational material for the aviation industry on this topic.

On 15 June 2006 at approximately 1630 Eastern Standard Time, during a scheduled flight from Hervey Bay, Qld, to Brisbane, Qld, the crew of the Fairchild Industries SA227-AC (Metro III) aircraft, registered VH-SEF, noticed that the cabin temperature was colder than desired. After adjustment to the auto and manual cabin temperature controls, the cabin temperature increased to a higher-than-expected range and could not be reduced. Shortly after, smoke was seen coming from the right-side cockpit air vents. The crew isolated the right bleed air system and diverted the aircraft to Maroochydore, Qld.

After examination of the aircraft's air-conditioning system, the right hot air mixing valve was replaced and the aircraft returned to service without further problem.

During the incident, the crew found that fitment of their emergency oxygen masks was ineffective, requiring them to hold the masks in place with one hand, and that the passenger address system was also ineffective in alerting the passengers to the emergency.

Only one minor injury in the form of sore ears was reported as a result of the incident.

As a result of this incident the Australian Civil Aviation Safety Authority issued an Airworthiness Bulletin to address maintenance aspects of flight crew oxygen masks.