Safety summary

What happened

At 1345 Central Standard Time on 2 October 2012, a loss of separation (LOS) occurred between a descending Boeing 717 aircraft, registered VH-NXQ (NXQ), operating a scheduled passenger service from Alice Springs to Darwin, Northern Territory, and a climbing Boeing 737, registered VH-VXM (VXM), operating a scheduled passenger service from Darwin to Melbourne, Victoria. The LOS occurred about 14 NM (26 km) south of Darwin, and the aircraft were under the jurisdiction of Department of Defence air traffic control (ATC) at the time of the occurrence.

Prior to the LOS, a predicted conflict alert was activated within the Australian Defence Air Traffic System (ADATS). After a short delay, the Approach controller instructed VXM’s flight crew to stop their climb at 9,000 ft. NXQ’s flight crew advised the controller of conflicting traffic below them and the controller instructed them to maintain 10,000 ft. Separation between the aircraft reduced to about 900 ft vertically as NXQ passed directly overhead VXM on a crossing track. The required separation standards were either 1,000 ft vertical separation or 3 NM (5.6 km) radar separation.

What the ATSB found

The ATSB determined that an already-assigned transponder code was allocated to the 717 in ADATS, which resulted in the 717’s call sign being incorrectly correlated in ADATS to an overflying aircraft that was in the general proximity of the 717. Manual processes to check the assigned transponder code with the code listed in ADATS were not conducted effectively. Due to local contextual factors and confirmation bias, the Darwin Approach controller and Approach Supervisor assumed that the radar return labelled as NXQ was correct, and they did not identify the error until after the conflict alert activated.

The ATSB identified safety issues relating to the Department of Defence’s (DoD’s) risk controls for ensuring transponder code changes were processed correctly, the expectancy in the Darwin approach environment about the relevance of radar returns with a limited data block, the risk assessment and review processes for the introduction of new equipment, and refresher training for compromised separation recovery actions.

What's been done as a result

The DoD issued a Safety Advisory to highlight to controllers the importance of the appropriate and timely actioning of all messages sent to the ADATS Problem Message Queue, for Planner controllers to confirm that correct transponder codes are allocated in the ADATS flight plan and to reinforce to controllers to take immediate action on all conflict alert and predicted conflict alert alarms. Following a September 2013 DoD review of the Comsoft Aeronautical Data Access System and its associated impact on the Planner role, Flight Data Operators have been introduced at a number of Defence air traffic control establishments to reduce workload in the Planner position.

The ATSB is not satisfied that the DoD has adequately addressed the safety issues regarding the provision of refresher training to air traffic controllers for the scanning of green radar returns and in compromised separation recovery requirements and techniques. As a result, the ATSB has made formal recommendations to the DoD to take further safety action on these issues.

Safety message

The ATSB reminds operational personnel such as controllers of the problems associated with confirmation bias when dealing with unusual situations and the importance of searching for anomalous indicators in such situations. The ATSB also reminds high-reliability organisations such as air traffic services providers that, even though they may have multiple levels of risk control in place to reduce safety risk, these controls need to be regularly evaluated to ensure that they are effective.

What happened

On 23 September 2012 at 1855 Eastern Standard Time, a Metro 3 aircraft registered VH-SEF (SEF) and operated by Brindabella Airlines, departed Narrabri on a scheduled passenger flight to Sydney, New South Wales. On board were seven passengers and two flight crew.

Passing through 10,000 ft, the Captain asked the First Officer (FO) for the transition checks which included a check of the cabin altitude by the FO. The transition checks were completed with no abnormalities found. During the climb, the Captain began to feel progressively worse and asked the FO to recheck the cabin altitude.  Before the FO could respond, the cabin altitude warning light illuminated at a cabin altitude of 17,000 ft. An emergency descent to 10,000 ft was performed.

As a result of this occurrence, the operator amended their standard operating procedures in regard to; the transition checks, maintenance schedule for the cabin altitude warning system and the re‑currency simulator training syllabus.

Flight crew are reminded of the dangers of hypoxia and the need to put oxygen masks on without delay if hypoxia is suspected.

Aviation Short Investigation Bulletin – Issue 14

At 1909:22 hours on 21 February 1980, Beech 200 aircraft, registered VH-AA V, collided with the western sea wall enclosing the extension of Runway 16/34, abeam the Runway 34 threshold, at Sydney (Kingsford Smith) Airport, New South Wales. The aircraft broke apart on impact and there was an explosive fire. The pilot and all twelve passengers were killed.

The accident occurred approximately 106 seconds after the aircraft had commenced take-off from Runway 25, on a scheduled flight to Temora, New South Wales.

The cause of the accident has not been determined, but the most likely explanation is that the aircraft was operated in a reduced power configuration which, under the prevailing conditions, rendered its single-engine performance critical in respect to aircraft handling.

On Saturday 9 June 2012 at around 0700 local time, an Impulse 180TDI amateur-built aircraft departed Tököl airfield, Hungary for a flight to Straubing, Germany. While en-route, the aircraft encountered adverse weather conditions, and following a Mayday radio call from the pilot, the aircraft impacted the ground, fatally injuring the pilot and passenger. 

The Bundesstelle für Flugunfalluntersuchung (BFU) of Germany is investigating this occurrence. In response to a request from BFU officers for technical assistance in the examination of a mobile phone and tablet device recovered from the accident aircraft, the Australian Transport Safety Bureau initiated an external aviation safety investigation in accordance with the provisions of the Transport Safety Investigation Act 2003.

The mobile phone and tablet device were subsequently received at the ATSB facilities in Canberra for analysis.  While the relevant logic circuitry of both devices was functional, security features enabled on both devices prevented a successful recovery of any navigational or location/tracking data that may have existed within the units. A report was issued to the BFU documenting the process and procedures undertaken and the devices were returned to the BFU.

For more information on this investigation, please contact the BFU: www.bfu-web.de/ 

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

What happened

At 1221 Western Standard Time on 23 September 2012, as a Piper PA‑28 aircraft, registered VH‑PZK (PZK), approached the threshold for runway 09 at Rottnest Island, Western Australia, the pilot observed an aircraft about 650 m ahead on the reciprocal heading at the same level. As the pilot of PZK initiated a sharp right turn he observed the other aircraft also turn right. The other aircraft was later identified as a Cessna 441 aircraft, registered VH‑VEJ (VEJ). The lateral distance between the aircraft reduced to 0.2 NM.

The pilots of both aircraft made all the necessary broadcasts on the common traffic advisory frequency (CTAF) although subsequent to the event, the pilot of PZK realised the aircraft’s radios were not working. VEJ was conducting a flight safety check flight of the Rottnest Island aerodrome and instrument approaches.

The flight safety checks being conducted by VEJ were on behalf of the Civil Aviation Safety Authority (CASA). The crew of VEJ was responsible for coordinating the flight check with aerodrome operators and CASA was responsible for communicating with aircraft operators. CASA had issued a press release on their website and the information was tweeted on twitter; however, no Notice to Airmen (NOTAM) was issued nor were any newspaper advertisements made.

As a result of this occurrence, the aircraft operator of VEJ advised the ATSB that they will not conduct flight safety check flights during busy periods at non-towered aerodromes. Additionally, CASA, in conjunction with the aircraft operator of VEJ, will ensure a NOTAM is issued for future flights to promulgate information applicable to this type of operation.

When operating outside controlled airspace, it is the pilot’s responsibility to maintain separation with other aircraft. For this, it is important that pilots utilise both alerted and unalerted see-and-avoid principles. Pilots should not assume that an absence of traffic broadcasts means an absence of traffic. CASA have published a number of Civil Aviation Advisory Publications (CAAPs) dealing with operations at non-towered aerodromes and the importance of not relying solely on radio broadcasts for traffic advice. In addition, the ATSB has published A pilot’s guide to staying safe in the vicinity of non-towered aerodromes (AR-2008-004(1)).

Aviation Short Investigation Bulletin - Issue 18

What happened

On 22 September 2012, a Piper PA-32 aircraft, registered VH-FAJ, was being operated on a private flight had an engine failure, 3 minutes after changing the fuel selection to the right tip fuel tank. The pilot changed the fuel selection back and conducted a forced landing. During the forced landing, the aircraft impacted two fences and sustained serious damage. The pilot and passenger were uninjured.

The aircraft had been stored in a hanger for nine months prior to the accident. An inspection of the aircraft wreckage found evidence of water in the right tip tank and airframe fuel filter bowl.

While the pilot stated that he conducted a thorough pre-flight inspection he considered that it was possible that he did not notice the water in the right tip tank fuel sample.

It is important that the testing of fuel drainage samples for water contamination are positive in nature and do not rely exclusively on the sensory perceptions of colour and smell, both of which can be unreliable.

Aviation Short Investigation Bulletin – Issue 14

Safety summary

What happened

On 23 September 2012, a stevedore working on board the general cargo ship Weaver Arrow while it was berthed in Newcastle NSW, died after being crushed under packs of aluminium ingots which toppled over during loading. Other stevedores raised the alarm and tried to help the crushed man but he showed no signs of life. Paramedics and police officers arrived on the scene shortly afterwards and confirmed that the stevedore was deceased.

What the ATSB found

The ATSB found that the stevedore was climbing down aluminium ingot packs to work on a lower tier of the cargo when the packs toppled over. It was usual for some stevedores to climb up or down ingot packs to work on different cargo tiers instead of using the ladders provided.

The investigation identified that the ingot cargo units or lifts (multiple packs of ingots strapped together) were inherently unstable and prone to toppling over. The stevedoring company’s procedure for loading aluminium products did not adequately address the risk of the cargo toppling over and the implementation of basic precautions, such as using ladders to climb between cargo tiers, was not effectively monitored or enforced.

The ATSB also found that stevedores often worked extended hours, exposing the company’s operations to a level of fatigue-related risk that had not been assessed and treated.

What's been done as a result

Immediately after the accident, Newcastle Stevedores, the stevedoring company, re-assessed the risks involved in loading aluminium ingots and revised its procedures for managing the risk of an ingot lift toppling. The primary measure was establishing an exclusion zone adjacent to a lift. This was included in a revised procedure for ingot loading with other measures such as the use of ladders. Steps to implement the procedure and ensure compliance included increased monitoring of loading operations. Other safety action taken includes an independent review of procedures, retraining of senior grade stevedores in hazard management, developing a process to reject hazardous lifts and suggestions to improve ingot lift configurations.

Patrick Ports and Stevedoring, the company responsible for preparing ingot packs for loading, has taken steps to enhance the stability of ingot lifts and a review is ongoing to identify other ways to address the issue. The main action taken is the addition of vertical straps to hold ingot stacks in a lift together (one strap for each pair of adjacent stacks).

Gearbulk Norway, Weaver Arrow’s manager, has made toppling of cargo a specific agenda item at the daily meetings between senior staff on board its ships and stevedores in all ports. Gearbulk has also introduced a policy of rejecting ingot lifts with broken pack, lifting or unitising straps for loading on any of its ships.

The ATSB has recommended that Newcastle Stevedores address the issue of stevedore fatigue. The ATSB has also issued two safety advisory notices to all stevedoring companies with regard to the issues concerning ingot loading and fatigue risk to promulgate a broad safety message.

Safety message

Individual stacks of aluminium ingots and other similar break-bulk cargoes (whether or not strapped together for carriage on ships) should always be considered unstable and prone to toppling over. No work should be undertaken in the vicinity of ingot stacks unless they have been secured to prevent toppling.

What happened

On 13 September 2012, a Boeing 737 aircraft, registered VH-YIO (YIO), departed Bali International Airport (Denpasar), Indonesia on a scheduled passenger service to Brisbane, Queensland.

The aircraft became established in the cruise and the seat belt sign was turned off. Shortly after, the crew observed opposite direction traffic on the aircraft’s traffic alert and collision avoidance system (TCAS), about 1,000 ft above and slightly to the left. The crew observed the aircraft pass to the left. Airservices Australia surveillance data indicated the aircraft passed with about 0.9 NM lateral and 1,400 ft vertical separation.

Soon after, the First Officer reported that they felt ‘cobblestone’ like turbulence. The aircraft then experienced a wake induced roll, initially to the right to a maximum angle of 6.5° and then left to 40.4°, with a 40 ft loss in altitude. As the roll to the left commenced, the crew immediately responded by applying full right aileron deflection. 

Surveillance data indicated that there was about 2.1 NM lateral, and 1,400 ft vertical separation and the correct air traffic control separation standards were being applied at the time. Nil injuries were received.

This incident demonstrated the value of periodic recurrent training, allowing the crew to react to the wake turbulence encounter intuitively and promptly. Furthermore, it is a timely reminder of the benefits of having the seat belt fastened, even when the seat belt sign is turned off, so that injuries during a turbulence encounter can be minimised.

Aviation Short Investigation Bulletin – Issue 17

On 16 August 2012 at approximately 1245 Coordinated Universal Time (UTC), a Jabiru J230 aircraft, registered N365R, was substantially damaged when it ditched in Gull Lake, New York, USA, following a loss of power. The two occupants were not injured.

As the accident occurred in the USA, the US National Transportation Safety Board (NTSB) is responsible for investigating this occurrence. As part of its investigation, the NTSB requested assistance from the Australian Transport Safety Bureau (ATSB) as the State of Manufacture of the aircraft and engine. In accordance with clause 5.18 of Annex 13 to the Convention on International Civil Aviation, the ATSB appointed an accredited representative to assist the NTSB and initiated an investigation under the Australian Transport Safety Investigation Act 2003.

The NTSB investigation is now approaching completion. A final investigation report into the circumstances of the power loss will be published and available from the NTSB’s website.

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

What happened

At 1526 Central Standard Time on 4 September 2012, a Bombardier DHC-8-202, registered VH-ZZJ (ZZJ), was cleared to take-off on runway 29 at Darwin airport, Northern Territory. At 1528 and before ZZJ had commenced take-off, an Aerospatiale AS.332L1, registered VH-LOJ (LOJ), called ready on runway 36. The Aerodrome Controller (ADC) cleared LOJ for take-off and instructed the pilot to maintain upwind.

The pilot of ZZJ heard the transmission and, believing that there would have been a risk of a collision if he commenced take-off, delayed his departure until after LOJ had crossed the intersection of the two runways. The action of the pilot of ZZJ to delay take-off reduced the likelihood of a more serious incident.

Air traffic services at Darwin are provided by the Department of Defence (Defence). The Defence investigation found that an unsafe take-off clearance had been issued to LOJ, resulting in a runway separation breakdown. Further, the ADC failed to monitor both ZZJ and LOJ during a critical phase of operation – take-off. The actions of the pilot of ZZJ, by delaying take-off, reduced the severity of the incident.

The pilot of ZZJ did not query the ADC’s instructions at the time and did not report the incident until two days later. The pilot of LOJ was not aware of the incident and the ADC did not recall the incident.

Aviation Short Investigation Bulletin – Issue 17