Confusion brings two aircraft too close together

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The benefits of having an operational transponder was recently demonstrated when a Fokker and Cessna’s close proximity activated the collision avoidance system.

The incident occurred on 22 May 2013 at Karratha Airport in Western Australia. A Fokker F28-100 was approaching Karratha on a scheduled passenger flight, flying about 10-11 NM behind a Boeing 717. A Cessna 310R was departing Karratha on a charter flight to Exmouth.

Air traffic control (ATC) advised the Cessna pilot of the Fokker’s presence, but made no mention of the Boeing. The Cessna pilot advised ATC that the traffic had been sighted. The pilot was then instructed to pass behind the aircraft and track to Exmouth. The Cessna pilot, believing the aircraft sighted was the Fokker, commenced tracking to Exmouth. The aircraft sighted was in fact the Boeing, which was ahead of the Fokker.

Shortly after, the Fokker’s traffic collision avoidance system (TCAS) activated. TCAS is an aircraft system that monitors the airspace around an aircraft for other aircraft equipped with a corresponding active transponder and gives warning of possible collision risks.

The pilot of the Cessna saw the Fokker approaching about 1 to 2 NM away and above, and descended the aircraft. Meanwhile, the crew of the Fokker complied with the TCAS instruction to climb. The Cessna passed safely about 700 ft below the Fokker, and both aircraft continued to their destinations.

The incident showed not only the benefits of the TCAS, but also highlighted the importance of ensuring that traffic information be relevant and sufficient.

The incident showed not only the benefits of the TCAS, but also highlighted the importance of ensuring that traffic information be relevant and sufficient.

Read the final report: TCAS warning between Cessna 310R, VH-AEY, and Fokker F28-100, VH-FKJ, near Karratha Airport, Western Australia, on 22 May 2013, which contains links to useful information on Class D airspace and the see-and-avoid principle.

Fire vehicle crosses runway during take-off

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A radio dead zone or an underpowered portable radio may have contributed to a loss of communication between an aircraft and an aviation rescue fire fighting (ARFF) vehicle.

On 26 May 2013, the pilot of a Piper PA-31 aircraft taxied for departure from Port Hedland for a flight to Karratha, Western Australia. The pilot made the necessary common traffic advisory frequency (CTAF) broadcast.

A few minutes later, an ARFF vehicle that had been operating on the eastern side of the airport, entered the taxiway to return to the fire station on the western side. The fire crew made a broadcast to announce their intention to cross the runway. Hearing no response and seeing no aircraft on the runway, the vehicle crossed the runway.

The pilot taxied onto the threshold of runway 32 and commenced the take-off roll. The pilot reported making the required CTAF broadcasts. As the aircraft became airborne, the pilot observed the fire vehicle crossing the runway about 500 m ahead.  The pilot judged it safer to continue the take-off. The aircraft passed over intersection of the runway and taxiway between 300 ft and 400 ft above ground. By that time, the fire vehicle had cleared the runway.

The crew of the ARFF vehicle had not heard any broadcasts, nor did they see the aircraft, possibly due to heat haze.  The ATSB examined recordings of transmissions broadcast on the Port Hedland CTAF and identified a number of broadcasts made by the pilot and the crew of the ARFF vehicle, however, the pilot’s broadcasts made near the runway threshold were not recorded.

The crew of the ARFF vehicle had not heard any broadcasts, nor did they see the aircraft, possibly due to heat haze.

At the time of the incident, the ARFF crew were using a portable radio as the Port Hedland ARFF service was in ‘setup’ mode awaiting approval by the regulator. The radio mounted in the vehicle had not been programmed to the correct frequency. Airservices Australia determined that the transmission power of the portable radio was lower than the radios mounted in the vehicle and that there may have been a radio dead zone near the runway 32 threshold.

Following the incident Airservices Australia is releasing a national operations safety note advising ARFF operators of the efficient use of aviation radio communications when driving on an airfield. They will also undertake a review of radio coverage at Port Hedland as part of radio commissioning works.

Read the final report: Runway incursion between Piper PA-31, VH-KLS and vehicle, at Port Hedland Airport, Western Australia, on 26 May 2013

Overloaded helicopter results in tragic fatality

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The ATSB investigation into a fatal helicopter accident has highlighted the dangers of operating overloaded helicopters.

The accident occurred on 9 December 2012, on a property near Mudgee, New South Wales. The Robinson R44 Raven I helicopter was being used to conduct aerial spraying activities. Following a number of spray runs, the helicopter failed to return to the refilling station. The helicopter was later found about 450m up a hill from the refilling station, having collided steeply with terrain. The pilot died in the accident.

The ATSB investigation found that, immediately before the accident, the helicopter was climbing up a hill at reducing speed. It was also about 33 kg above the maximum allowable weight of 1,089 kg and, crucially, too heavy for a high hover at full engine power. As the helicopter’s speed reduced below about 10 kt (20 km/h) it began to descend. The pilot did not have enough time, and possibly height, to recover and the helicopter hit a tree, before crashing steeply into the ground.

The accident tragically demonstrates the dangers of loading helicopters beyond their recommended limits, especially when undertaking operations where performance is critical, such as low flying or aerial spraying operations.

The accident tragically demonstrates the dangers of loading helicopters beyond their recommended limits, especially when undertaking operations where performance is critical, such as low flying or aerial spraying operations. Pilots should always follow manufacturers’ performance data to avoid the dangers associated with this accident.

Read the final report: Loss of control involving Robinson R44 helicopter, VH-WOH, 20 km south-west of Mudgee, New South Wales, on 9 December 2012

Landing gear collapses after incorrect installation

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The landing gear collapse on a Raytheon B200 was due to the incorrect installation of a component, according to the ATSB investigation report. On 27 March 2013 a Raytheon B200 aircraft was being operated as an aero-medical flight between Darwin and Port Keats, NT. On board were the pilot and two flight nurses.

While preparing to land at Port Keats, the pilot selected the landing gear down. Only the nose landing gear (green) light illuminated. The unsafe landing gear (red) warning light remained illuminated for the left and right landing gear. The pilot cycled the landing gear and the landing gear circuit breaker tripped. The pilot reset the circuit breaker in accordance with the aircraft’s quick reference handbook, but it tripped again.

The pilot decided to return to Darwin and advised air traffic control (ATC) of the situation. During the flight the pilot completed the unsafe gear checklist including using the emergency gear extension system. While in the circuit area, another company pilot and Darwin ATC reported that the landing gear appeared to be down.

During landing, the right landing gear touched down first, but when the left wheel touched, the aircraft started to sink. The pilot transferred the weight to the right, shut down the left engine and feathered the propeller.  He then shut down the right engine and feathered the propeller. The left wing struck the runway and the aircraft skidded to a stop. The pilot and flight nurses exited the aircraft, without injury. The aircraft sustained substantial damage.

During landing, the right landing gear touched down first, but when the left wheel touched, the aircraft started to sink.

The left landing gear had been installed on the aircraft on 22 March 2013 and this was the first flight with the replaced gear. The operator found that a washer had not been installed in the assembly. CASA’s investigation found that there was no conclusive way to determine when the washer installation error had occurred. The manufacturer subsequently commented that the missing washer would not have caused the landing gear to fail to lock down. They believed it was more likely that a drag brace had either, not been installed, or had been rigged incorrectly, or that another landing gear assembly or maintenance error occurred, causing the circuit breaker to trip resulting in the accident.

Following the occurrence, the operator inspected all of its B200 aircraft and issued a safety bulletin to staff. The training and checking department were reviewing its proficiency checking for pilots in relation to this type of landing. The manufacturer is clarifying its maintenance manual.

Read the final report: Left main landing gear collapsed involving a Raytheon B200, VH-ZCO, Darwin Airport, Northern Territory, on 27 March 2013

Aircraft loses power on take off

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A total power loss of a Mooney M20J at Canberra Airport highlights the importance for pilots of retaining currency in emergency procedures.

On 2 June 2013, the pilot conducted his pre-flight checks before a flight from Canberra to Albury. The pilot refuelled at Albury the day before and had noted that the bowser had been surging, turning on and off and pumping air. As it had rained the previous night, the pilot paid particular attention to conducting pre-flight fuel drains and checking for water, with none found.

During the take-off run, the pilot reported that all cockpit indications were normal, the aircraft attained full power and achieved the expected rotate speed followed by a positive rate of climb.

Seconds after the pilot retracted the landing gear at about 100 ft above the ground, the engine suddenly stopped. The pilot lowered the landing gear, switched fuel tanks and lowered the aircraft nose to increase airspeed.

During the take-off run, the pilot reported that all cockpit indications were normal, the aircraft attained full power and achieved the expected rotate speed followed by a positive rate of climb.

While the pilot was conducting emergency checks the aircraft descended and landed on the runway heavily on the left wing and landing gear, with the propeller striking the ground. The aircraft was substantially damaged, and the pilot sustained minor injuries.

Inspection of the aircraft’s engine after the accident revealed water in the left-wing fuel tank, fuel system and fuel injector lines. The pilot reported that he had contacted the Mooney Service Centre and had been advised that incorrect re-sealing of the M20 series aircraft fuel tanks could allow 1 to 2 litres of water to be retained in the wing, which could not be drained.

A pre-take-off briefing can remind the pilot of procedures during take-off at low altitude. Controlling the aircraft at low altitude and maintaining airspeed can reduce the severity of such incidents.

Read the final report: Total power loss involving a Mooney M20J, VH-NFP, at Canberra Airport, Australian Capital Territory, on 2 June 2013

Engine Failure — Airbus A380

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On 11 November 2012 an Emirates A380 departed Sydney Airport for Dubai, United Arab Emirates.  While climbing through an altitude of approximately 9,000 feet the crew heard a loud bang accompanied by an engine No 3 exhaust gas temperature over-limit warning. Shortly, thereafter, the engine went through an uncommanded shutdown. The crew jettisoned fuel and returned to Sydney where the aircraft landed safely.

The investigation found that the increase in exhaust gas temperature and subsequent engine shutdown was the result of significant internal damage that had initiated within the high pressure turbine (HPT) module. The damage resulted from the effects of stage-2 nozzle distress likely caused by exposure to hotter than expected operating temperatures. The nozzle distress had led to eventual failure and separation into the gas flow path. Over the preceding weeks two other engines within the operator’s fleet had been similarly affected.

While the distress to the HPT was severe enough to result in an in-flight engine shutdown, the associated risks to the continuation of the flight were relatively low...

The engine had operated for a total of 15,318 hours and 1,876 flight cycles since new. Of that, 6,748 hours and 793 flight cycles had accumulated since the last workshop visit. At the time of the occurrence there were no outstanding items on the engine’s maintenance log. During the preceding flight of the aircraft, the manufacturer’s engine health and trend monitoring program had identified a performance trend shift with this particular engine and it was due to be inspected on return to the main base in Dubai.

The engine’s manufacturer, Engine Alliance had issued a service bulletin in June 2010 for the replacement of affected stage-2 nozzle segments with new more durable components during the next workshop visit when the HPT stage-2 was removed from the engine. Following this occurrence, another service bulletin was released on 6 December 2012, requiring the direct inspection of the nozzle segments that had not been replaced. The US Federal Aviation Administration also released an Airworthiness Directive that required inspection of the nozzle segments and their removal from service if distress was identified. 

While the distress to the HPT was severe enough to result in an in-flight engine shutdown, the associated risks to the continuation of the flight were relatively low, given the failure had been contained and the operators procedures were effective in managing the shutdown. This occurrence pointed to the value of real-time engine condition monitoring since advanced warning of engine degradation and efficiency loss allows inspection and corrective action to be taken before damage progresses to cause a shutdown. 

Read the final report: Engine failure involving Airbus A380, A6-EDA, near Sydney Airport, New South Wales, on 11 November 2012

Fatal collision with terrain

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A fatal helicopter accident on a mountain peak left two dead and one seriously injured.

On 8 September 2011, a chartered Eurocopter AS350BA, with a pilot and two passengers on board, was travelling to a helicopter landing site in the Shoalwater Bay military training area in Queensland. The crew were assisting in maintenance of landing sites throughout the area.  The site they were visiting was situated atop the south-eastern peak of Double Mountain. Located at an elevation of 2,421 ft, (738 m), the site was surrounded by trees on three sides with a mast and antenna array on the other.

The direction from which the pilot had approached the site was probably with a wind from the right and ... would have been vulnerable to any unexpected turbulence.

The pilot made four passes of the helipad and then, while hovering or moving at a low speed, the helicopter climbed and started to rotate left. The pilot was unable to control the rotation, and the helicopter descended into the trees before colliding in an inverted attitude with the ground. The pilot and front seat passenger were fatally injured, and the rear seat passenger received serious injuries. The helicopter was substantially damaged and there was no fire.

The ATSB’s investigation could not positively establish the reason for the pilot’s loss of control, although it is most likely to have resulted from environmental and operational factors. The direction from which the pilot had approached the site was probably with a wind from the right and, during his inspection of the site, would have been vulnerable to any unexpected turbulence.

It is part of the normal competency training for licenced helicopter pilots to receive instruction in pinnacle and confined area operations. Those skills, however, are degradable and it is vitally important to ensure that pilots’ competency and skills are appropriate to the task to which they are assigned. 

Read the final report: Loss of control involving Eurocopter AS350BA, VH-RDU, 93 km north of Rockhampton, Queensland, on 8 September 2011

Flash flood results in derailment

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The ATSB has warned rail transport operators of the importance of having robust systems to monitor and mitigate the risks to infrastructure from significant weather events. This warning comes after an accident near Roto in New South Wales which left a locomotive derailed and several of its trailing wagons damaged.

The accident occurred on 4 March 2012 when the train, consisting of two locomotives and 45 freight wagons, was travelling from Sydney to Perth. There had been a significant amount of rain in the region of Roto that morning—more than a 50-year rainfall intensity event. The Bureau of Meteorology had issued a severe weather warning for flash flooding for the district. As the train approached Roto, light rain was still falling. 

A mentor driver was supervising the trainee driver who had control of the train when he observed ‘white water’ flowing over the track ahead. Under the mentor’s instructions, the trainee applied the train brake. Then the mentor driver intervened directly: he moved over to the controls and applied full dynamic braking, and then the full independent and service brake as well. He then resumed his seat and instructed the trainee driver to brace, should the train not stop before entering the water. It didn’t. 

The flooding had caused scouring of the track formation, compromising its capacity to support the train.

As the train entered the water, the crew felt significant impacts with the locomotive hitting two distinct dips in the track. The second dip sent water up to cover the locomotive windscreen. The lead locomotive remained on track, but the trailing locomotive uncoupled and collided with the rear of the lead locomotive. No one was injured, although the locomotives, trailing wagons and the track were damaged.

The ATSB determined that runoff from the heavy rain had caused a flash flood event. The floodwater exceeded the capacity of a drainage culvert, which resulted in water overtopping the track formation with ballast and sub-grade scouring on either side of the culvert. The magnitude of that scouring meant that the track could not support the weight of train 7SP3 as it passed over the affected areas. The resulting deformation in the alignment of the track initiated the derailment. 

The ATSB also identified a safety issue with the track manager’s systems and operational procedures. They provided only limited information and guidance to network control staff in identifying and assessing the potential threat from the weather.

The track manager is now trialling the use of flood sensors at high-risk locations and has engaged the services of a third party to provide early warning information on potential high-risk weather events.

Read the final report: Derailment of freight train 7SP3, near Roto, New South Wales, on 4 March 2012

Electric fence snares aircraft

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An amateur-built 1933 Pietenpol Air Camper collided with terrain after the landing gear caught the top wire of an electric fence.

The ATSB is warning pilots that when they are not operating from a designated landing area they need to ensure the area is suitable. This comes after an accident that occurred on 19 May 2013 near St Leonards, Tasmania. The pilot was taking a passenger on a scenic flight around Launceston, starting from a paddock behind his home. He had operated the aircraft from the paddock in the past, but not for a few years. A week before the accident, the pilot surveyed the area by car.

On surveying the accident site, the pilot realised that the aircraft’s landing gear had caught the top wire of an electric fence he had not noticed...

The aircraft was operating normally and became airborne at about 35 knots indicated airspeed. The pilot held the aircraft low, aiming to clear a fence at the end of the paddock. Nearing the fence, the pilot heard a loud noise and the nose of the aircraft jolted to the right.

The airspeed quickly decreased, as the pilot attempted to hold the wings level. After initially climbing to about 10 ft, the aircraft impacted the ground, breaking the landing gear. The aircraft skidded on its nose and then pitched over onto its back, breaking the propeller.

Both the pilot and the front seat passenger exited the aircraft without injury. On surveying the accident site, the pilot realised that the aircraft’s landing gear had caught the top wire of an electric fence he had not noticed, located a short distance before the paddock’s main fence.

Pilots need to assess proposed landing areas carefully, especially if they are not using a designated landing area. A thorough survey of the area to be used for take-off and landing should be completed immediately prior to use.

Read the final report: Collision with terrain involving a Pietenpol Air Camper, VH-ARW, 9 km north of Launceston, Tasmania, on 19 May 2013

Two safety incidents within a week

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Two airspace-related events around the same aeroplane landing area have shown the importance of pilots identifying potential hazards on their planned flight routes, and remaining focused on their surroundings.

Both incidents took place at Nagambie, Victoria. The first incident occurred on 3 May 2013, when the pilot of a Cessna 182 was conducting parachute operations over Nagambie. At the same time, the pilot of a Piper PA-28 aircraft was conducting a private flight from Mangalore to Bendigo, Victoria. He planned to fly from Mangalore to the Nagambie Township and then to Bendigo, to avoid a restricted area and parachute operations danger area.

In both occurrences, the pilots were operating on the see-and-avoid principle of air traffic safety.

A Danger Area is one in which dangerous activity (such as skydiving) takes place, so pilots entering that area need to take appropriate precautions. In contrast, restricted areas are areas of airspace into which pilots cannot fly without permission.

After completing the parachute drop, the Cessna conducted a circling descent, joining the base leg of the circuit and making a broadcast on the radio.

When about 6 NM to the west of the Nagambie Township, maintaining 2,500 ft, the pilot of the Piper saw the Cessna above, on descent, flying from left to right. The Piper pilot took action to avoid the Cessna.

As the pilot of the Cessna entered the danger area, at around 2,000 ft, he saw the Piper in his 12 o’clock position taking avoiding action. He banked his aircraft heavily to avoid the Piper. He estimated the aircraft came within 50 ft of each other.

The second incident occurred five days later, when the pilot of a Bell 206 helicopter was conducting a private flight from Mangalore to Echuca, Victoria, flying via the Nagambie Township to avoid the restricted area, maintaining 1,000 ft.

After passing near the Nagambie Lakes area, the pilot received a call on the radio from the drop zone safety officer on the ground at Nagambie advising that he had just flown over a parachuting landing area. At that time, five parachutists had just landed and six were still airborne.

In both occurrences, the pilots were operating on the see-and-avoid principle of air traffic safety. An ATSB research report, Limitations of the See-and-Avoid Principle, examines the potential risks that can arise in these scenarios.

Read the final report: Two airspace related events, at Nagambie (ALA), Victoria, on 3 and 8 May 2013