At approximately 1325 hours Eastern Standard Time on 26 September, 1970, a Piper PA23-250 Aztec aircraft, registered VH-SPM, collided with the precipitous face of a ravine, 490 feet below the main line of a ridge, on the eastern slopes of Mt. Scratchley in the Territory of Papua. The aircraft was engaged on a charter flight for the carriage of passengers and baggage from Kokoda to Port Moresby. The aircraft reported its departure from Kokoda but, when it did not arrive at Port Moresby, search and rescue procedures were initiated. The wreckage was sighted on 1 October, 1970 in dense rain forest, 10,100 feet above mean sea level. At first, the efforts of ground rescue parties to reach the wreckage were frustrated by extremely bad weather conditions, the high altitude and the precipitous terrain. Thirteen more days elapsed before a member of a mountain rescue party reached the accident site to find that the aircraft had been destroyed by impact forces and the pilot and the three passengers on board· had suffered fatal injuries.

What happened

On 5 October 2012, a Beech 1900 VH-EMK was operating a passenger carrying charter flight from Darwin to Jabiru, Northern Territory.

With no response to their broadcasts on the local Jabiru aerodrome frequency, and no other aircraft observed on the aircraft traffic monitoring system, the crew continued their approach onto runway 09 at Jabiru. When approaching 5 NM to touchdown, the crew observed a ‘glint’ on the runway and broadcast on the local frequency, again with no response.

At about the same time, an Airparts FU-24, VH-HVP, had broadcast entering and back-tracking the runway for a departure in the opposite direction. The pilot of HVP heard a broadcast from EMK and believed they were further back in the approach.

As HVP was commencing the take-off run, the crew in EMK and the pilot in HVP saw each other and both immediately initiated avoidance manoeuvres.

It was found that the radio in HVP had not been broadcasting, due to an incorrectly positioned switch.

As a result of this incident, the operator of VH-HVP has arranged for all pilots to re-visit company Standard Operating Procedures on radio transmissions and low-level survey flying.

This incident demonstrates the importance of checking the serviceability of radio equipment prior to flight. In particular, the use of available resources such as AFRU for ensuring the radio is transmitting.

Aviation Short Investigation Bulletin – Issue 15

Safety summary

What happened

On 28 September 2012, an en route air traffic controller acknowledged a Route Adherence Monitor (RAM) alert in respect of a Boeing Company 737‑8BK aircraft, registered VH-VUM (VUM), on a scheduled passenger service between Sydney, New South Wales and Brisbane, Queensland. Believing that VUM was destined for Newcastle Airport under Department of Defence air traffic control jurisdiction, the controller erroneously inhibited the flight data record (FDR) for VUM. This action cancelled the RAM alert.

The inhibition of the FDR, in combination with the controller’s altitude filter being set at a lower flight level than appropriate to the combined sectors under the controller’s jurisdiction, meant that VUM’s FDR registered as a ‘not concerned’ aircraft track. Subsequently, due to this ‘not concerned’ status, the controller did not see or interrogate VUM’s FDR for the rest of the time it was under their jurisdiction. Similarly, the FDR did not attract the attention of two Inverell sector controllers after it entered and crossed their sector until they responded to a frequency change request from the flight crew of VUM.

There was no loss of separation with other aircraft for the resulting period that the aircraft operated without the active provision of ATC services and, during the course of the occurrence, two-way communications in controlled airspace remained available. However, maintenance of the minimum aircraft separation standards during this period was not assured. There was a loss of separation assurance.

What the ATSB found

High-reliability systems like air traffic control have many layers of controls to minimise risks associated with operational hazards. These controls were ineffective in this case as a result of a number of factors, including human perception and attention issues, the training of controllers with regard to ‘not concerned’ tracks, and the level of system protection against the potential impact of such tracks. Specifically, error‑tolerant system designs that aid in the detection and recovery of inadvertently-inhibited tracks offer another defence against this type of occurrence.

Two safety issues were identified as a result of this investigation. The first relates to the provision of awareness training for en route controllers who are routinely exposed to ‘not concerned’ radar tracks, which can lead to a high level of expectancy that such tracks are not relevant for aircraft separation purposes. The second issue relates to the limited protections against a controller mistakenly inhibiting an aircraft and need for procedures to account for the limitations in the interoperability between the Australian Advanced Air Traffic System/Australian Defence Air Traffic System.

What's been done as a result

In response to the occurrence, Airservices has amended its air traffic controller ab-initio training exercises to include ‘not concerned’ track scenarios to ensure that training emphasised the importance of scanning ‘not concerned’ radar tracks. The scenarios will also be included in operational simulation training where appropriate. Furthermore, Airservices will use this occurrence to raise awareness of black tracks and the need to scan ‘not concerned’ tracks amongst its air traffic control staff.

In respect of equipment interoperability, Airservices and the Department of Defence are currently working towards implementing a harmonised joint civil military air traffic service system via the OneSky Program. Once implemented this system will increase air traffic management interoperability between both organisations.

Safety message

This occurrence highlights the fallibility of human attention/perception and the resulting risk of involved parties being ‘primed’ to the circumstances of an occurrence to the extent that they automatically (but incorrectly) perform actions that they perceived were correct. There is the potential for additional error-tolerant design improvements to complement existing air traffic system human machine interface risk controls to reduce the likelihood of such behaviour.

Humans can also experience difficulty detecting display targets that are subtle, unexpected and deemed of low information value. This occurrence showed a reduced awareness among controllers of the potential impact of black, ‘not concerned’ tracks in an en route airspace environment, which might be addressed by additional controller training or through an integrated air traffic management system.

Safety summary

What happened

At about 1107 on 1 October 2012, the pilot-owner of a vintage de Havilland DH-84 Dragon Mk 2, registered VH-UXG, took off on a private flight from Monto to Caboolture, Queensland. On board with the pilot were five passengers, baggage and equipment. The pilot was not qualified, and the aircraft not equipped for instrument flight. The weather on the coast and extending inland included low clouds and rain.

At 1315, the pilot radioed air traffic control (ATC) and requested navigation assistance, advising that the aircraft was in cloud. Over the next 50 minutes ATC provided assistance to the pilot and a search and rescue (SAR) helicopter was dispatched to the area. From the pilot’s radio calls it was apparent that he was unable to navigate clear of the cloud. Radio contact was intermittent and no transmissions from the aircraft were received after 1405.

An extensive search was initiated, and the aircraft wreckage was located on 3 October in high terrain. The aircraft was destroyed and there were no survivors.

What the ATSB found

With no or limited visual references available in and near cloud, it would have been very difficult for the pilot to maintain control of the aircraft. After maintaining control in such conditions for about an hour, and being unable to navigate away from the mountain range, the pilot most likely became spatially disoriented and lost control of the aircraft before it impacted the ground.
Due to the limited radio and radar coverage in the area, the ability of ATC and the SAR helicopter to assist was limited. However, the ATSB found that there were areas of potential improvement in the management of in-flight emergencies and coordination between ATC and SAR aircraft.

What's been done as a result

Airservices Australia and the Australian Maritime Safety Authority agreed to conduct a comprehensive review of their existing memorandum of understanding to ensure the effectiveness of collaborative in-flight emergency responses. The review is anticipated to be completed by the first quarter of 2014.

Safety message

Though it remains unclear precisely how the aircraft came to be in instrument conditions, this accident highlights the importance of pre- and in-flight planning and decision-making in limiting exposure to risk. It is important for pilots to incorporate approved weather forecasts, knowledge of the terrain, and diversion options into their flight planning, to plan for contingencies prior to and throughout a flight, and to carry out those plans well before encountering difficulty.

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