At 1400 Eastern Daylight-saving Time on 23 March 2012, as a Vans RV-10 registered VH-PGX (PGX) became airborne at about 65 kts, the pilot of PGX observed another aircraft enter runway 22 at Taree, NSW and turn right for the threshold of runway 04. PGX passed directly overhead the other aircraft at about 300 ft.

The other aircraft was identified as a Regional Express, SAAB Aircraft Co 340B registered VH-ZLH (ZLH). After the incident, the captain of ZLH established contact with PGX and neither aircraft experienced problems communicating with the other.

As a result of the incident, the operator of ZLH will amend procedures to more clearly define radio procedures for both flight crew and ground staff at those Common Traffic Advisory Frequency aerodromes without an Aerodrome Frequency Response Unit.

This incident highlighted the need for pilots to apply all available methods to maintain separation with other aircraft when operating outside controlled airspace. These methods include the utilisation of both alerted and un-alerted see-and-avoid principles, the use of on-board collision avoidance systems where fitted and all available aircraft lighting.

The pilot of a Piper PA‑34 aircraft, registered VH-FEJ (FEJ), submitted a flight plan from Archerfield to Cairns via Townsville, Queensland. Prior to departure, air traffic control (ATC) at Archerfield updated the flight plan from visual flight rules (VFR) to instrument flight rules (IFR) at the pilot’s request.

The updated flight plan was transmitted via a change message to the various ATC agencies responsible for the aircraft. Townsville ATC, operated by the Department of Defence, utilised computer printed flight progress strips (strips) and the strip for FEJ was printed prior to the change message being processed, indicating that FEJ was a VFR flight.

When the pilot of FEJ contacted Townsville Approach, he requested a runway 01 instrument landing system approach. The Approach controller cleared the aircraft to track direct to the initial approach fix and, once the aircraft was within 36 NM, cleared the pilot of FEJ to descend to 4,000 ft.

Shortly after, the Approach controller became concerned about FEJ maintaining visual meteorological conditions given the weather in the area and queried the pilot on the aircraft’s flight category. On being advised that FEJ was an IFR flight and in cloud, the Approach controller immediately instructed the pilot to stop the descent at 5,500 ft. By the time the pilot was able to arrest the aircraft’s descent, FEJ had reached 5,200 ft. Though FEJ did not descend below the lowest safe altitude on the aircraft’s track, terrain clearance on track was not assured until FEJ climbed back to 5,500 ft. Shortly after, the pilot became visual and FEJ landed without further incident.

As a result of this occurrence, the Department of Defence has advised the ATSB that controllers are now required to check flight progress strips thoroughly prior to passing them to Approach, ensuring that the data was correct.

Aviation Short investigation Bulletin Issue 21

On 28 February 2012, an Airbus A340-313X aircraft, Portuguese registered CS-TQM (TQM), was operating on a chartered service from Sydney, New South Wales to Darwin Airport, Northern Territory.

On approach into Darwin, the crew noted heavy rainfall near the threshold of runway 29 and requested wind information from the Darwin tower air traffic controller. At that time, the windsock at the threshold was indicating 5 kts tailwind and the approach was continued. In the final stages of the approach, the rainfall increased significantly, and the aircraft deviated below the glideslope. On touchdown, the wind suddenly increased to an 18 kt tailwind, possibly due to a microburst, and the aircraft landed heavily.

Subsequent engineering inspection revealed a crack in the No. 1 engine rear attachment bolt retainer. Components from the left and right main landing were also replaced.

As a result of the incident, the operator has

• Introduced go-arounds from 50 ft and go-arounds from immediately after touchdown into simulator training sessions.
• Developed an awareness program to increase the go-around mind set among flight crew, including allowing First Officers to initiate a go-around without the need for consent from the Captain.

On Wednesday 21 March 2012 at 0530 Eastern Daylight-Savings Time an aerodrome reporting officer (ARO) reported a runway edge light outage at Williamtown Airport, New South Wales. A further inspection during daylight revealed a broken runway edge light and wheel marks in the grass adjacent to the runway. The evidence was consistent with an aircraft departing from the sealed operational readiness platform adjacent to the runway threshold onto the grass and colliding with the runway edge lighting.

The distance between the wheel marks was consistent with a Beechcraft Kingair aircraft. Air traffic control records show that no other aircraft with this wheel arrangement had operated between the runway inspections.

The pilot of a Beechcraft Kingair 350, recalled rejecting the take-off on departure from Williamtown Airport on the night of 19 March 2012 due to asymmetric power resulting in the aircraft deviating left of centreline. The pilot did not believe that the aircraft left the sealed runway area. A number of other Kingair aircraft operated at Williamtown during the considered period.

It was not possible to determine when the runway excursion occurred, however the wheel marks indicated that a Kingair may have inadvertently lined up on the runway edge lighting during take-off. A paper published by the ATSB, "Factors influencing misaligned take-off occurrence at night" highlighted the risk factors for a misaligned take-off.

What happened

On 12 February 2012, the flight crew of a Boeing 737 aircraft, registered VH-TJS and operated by Qantas Airways Limited, was conducting a scheduled passenger service from Sydney, New South Wales to Canberra, Australian Capital Territory. Due to scheduled maintenance the instrument landing system at Canberra was not available and the crew prepared for an alternate instrument approach that provided for lateral but not vertical flight path information. The flight was at night with rain showers and scattered cloud in the Canberra area.

Shortly after becoming established on the final approach course with the aircraft’s automatic flight system engaged, the flight crew descended below the minimum safe altitude for that stage of the approach. The crew identified the deviation and levelled the aircraft until the correct descent profile was intercepted, then continued the approach and landed. No enhanced ground proximity warning system alerts were generated, as the alerting thresholds were not exceeded.

What the ATSB found

The ATSB found that at the time of the occurrence the automatic flight system was in the level change mode rather than the vertical navigation mode specified by the operator for such approaches. While in that mode the flight crew had selected an altitude lower than the applicable minimum safe altitude, with the effect that unless the crew intervened, the aircraft would descend to that lower altitude. The flight crew then allowed the aircraft to continue descending in the level change automatic flight mode through the segment minimum safe altitude, reflecting a temporary loss of situation awareness.

Safety message

During those phases of flight when terrain clearance is unavoidably reduced, such as during departure and approach, situation awareness is particularly crucial. Any loss of vertical situation awareness increases the risk of controlled flight into terrain. This occurrence highlights the importance of crews effectively monitoring their aircraft’s flight profile to ensure that descent is not continued through an intermediate step-down altitude when conducting a non-precision approach.

Safety summary

What happened

On 19 March 2012, Pacific National ore train 4460S travelling on the interstate main line between Port Augusta and Port Pirie collided with an eastbound motor vehicle on the Port Flinders Causeway Road level crossing, about 10 km south of Port Germein in South Australia. The level crossing was controlled by passive approach warning signs and a ‘Stop’ sign at the crossing.

There were two occupants in the motor vehicle. The passenger was fatally injured and the driver suffered serious injuries. The crew of the train were physically unhurt.

What the ATSB found

The ATSB found that the driver of the road vehicle involved in the collision did not come to a complete stop at the railway crossing and entered the crossing in the path of the approaching ore train. The ATSB concluded that the motorist’s attentional resources might have been diverted during a critical period when they would normally have stopped to look for a train.

What's been done as a result

Minor corrective action was taken to replace a missing ‘Railway Crossing’ assembly which should have been situated on top of the ‘Stop’ sign on the western approach to the crossing. The absence of the ‘Railway Crossing’ assembly was not considered a factor that contributed to the collision as it was found that the motorist regularly used the crossing and the ‘Stop’ sign was still in place.

Safety message

The occurrence highlights the need for drivers of motor vehicles to be vigilant and obey road traffic signage.

Safety summary

What happened

On the morning of 4 March 2012, freight train 7SP3 operated by Pacific National derailed after entering floodwaters that had overtopped the track near Roto in New South Wales.

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

The lead locomotive remained on the track but the trailing locomotive derailed and uncoupled. None of the trailing wagons derailed although a number sustained damage. The flooding and subsequent derailment of the second locomotive of train 7SP3 damaged approximately 130 m of track. The crew were shaken, but physically unhurt.

What the ATSB found

The ATSB determined that runoff from the heavy rain that had fallen in the catchment area adjacent to Roto the morning of 4 March 2012 caused a flash flood event. The volume of 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 the 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 found that the track manager’s systems and operational procedures provided limited information and guidance to assist the network control staff in identifying and assessing the potential threat to the safety of rail traffic resulting from the significant localised weather event.

What's been done as a result

The track manager is 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.

Safety message

It is essential that rail transport operators have robust systems in place to monitor and mitigate the risks to infrastructure from significant weather events to ensure that the safety of rail operations is not compromised.

Why the ATSB is doing this research

One of the main objectives of air traffic services (ATS) is to prevent the collision of aircraft. Aircraft separation standards are set to ensure that the chance of a mid-air collision is very remote. When they are infringed, there are fewer defences left to guard against a mid-air collision. This ATSB research investigation looks at loss of separation (LOS) incidents in Australian airspace to understand how often they occur and in what contexts, how and why they are occurring, and whether there are any wider implications that the air traffic system is not functioning appropriately.

What the ATSB found

Although there had been an increase in the number of occurrences reported to the ATSB over the 2 years ending in June 2012, there were fewer LOS occurrences during that period than during 2005 to 2008. Traffic levels have generally increased during the same period. A LOS between aircraft under air traffic control jurisdiction happens on average about once every 3 days. In almost 90 per cent of LOS occurrences, there was no or minimal risk of aircraft colliding. On average, however, there are six occurrences per year where an elevated risk of collision exists. There have been no mid-air collisions in Australia between two aircraft under ATS control.

The investigation found that military controlled terminal area airspace in general, and all airspace around Darwin and Williamtown in particular, had a disproportionate rate of LOS (for civilian aircraft). Most of these LOS occurrences were contributed to by air traffic controller actions. This may be a result of the nature of aircraft operations and airspace constraints at some military airports, leading to reduced use and effectiveness of strategic separation defences, thereby placing more responsibility for separating aircraft directly onto the controllers. Furthermore, as military ATS are not subject to safety oversight by the Civil Aviation Safety Authority (CASA), there is no independent assessment and assurance as to the safety of civilian aircraft operations at military airports.

In civil airspace, LOS occurrences attributable to pilot actions are not monitored as a measure of airspace safety nor actively investigated for insight into possible improvements to air traffic service provision. As about half of all LOS incidents are from pilot actions, not all available information is being fully used to assure the safety of civilian airspace.

What's been done as a result

The ATSB has issued recommendations to the Department of Defence to review all processes and controls in place for aircraft separation in military ATS and to CASA to review whether its current level of involvement with military ATS is sufficient to assure the safety of civil aircraft operations. The ATSB also recommends using all available information, including pilot attributable LOS occurrences, to assure the safety of civilian airspace, and will itself investigate all serious LOS incidents.

Safety message

Aircraft separation is a complex operation with many levels of defences to avoid errors and to safely manage the results of the errors that will inevitably be made from time to time by air traffic controllers and pilots. The defences ensure that even if a LOS does occur, the chance of an aircraft collision is still very remote. Safety could be enhanced through understanding and addressing the reasons for the disproportionate rate of LOS occurrences involving civil aircraft in military airspace, and through the ongoing monitoring and investigation of all LOS incidents in civil airspace.

On 21 February 2012, at about 0900 Eastern Daylight-saving Time, at about 8 NM east of Gunnedah, New South Wales, a Piper aircraft company PA-39 aircraft registered VH-ICS (ICS) and a Pacific Aerospace CT/4B aircraft registered VH-YCR (YCR) were conducting instrument flight rules (IFR) flying training operations, in visual metrological conditions on a reciprocal track between Tamworth and Gunnedah. There was a flying instructor and two students on board ICS and a flying instructor and one student on board YCR.

YCR received traffic advice from Brisbane Air Traffic Services (ATS) on two other aircraft in the area below 5,000 ft, including ICS. YCR was nearing Gunnedah at 6,000 ft above mean sea level, and broadcast their intention to over-fly Gunnedah at 6,000 ft, on the Gunnedah common traffic advisory frequency. ICS then requested traffic information for a departure from Gunnedah to Tamworth, at 7,000 ft and later advised Brisbane ATS that they were 5 NM outbound from Gunnedah and passing 6,000 ft. Both aircraft were on the same bearing and unable to contact each other; both took evasive action at 6,000 ft. The PIC of YCR estimated that at the time of the event their separation was 1 NM laterally.  Neither crew sighted the other aircraft.

This incident highlights the importance of applying the principles of 'see and avoid' in conjunction with an active listening watch and clear communications when operating in the vicinity of a CTAF.

Aviation Short Investigation Bulletin - Issue 11

On 21 February 2012, a Robinson Helicopter Company R22 Beta helicopter, registered VH-HRY, collided with terrain 95 km south-west of Springsure aircraft landing area (ALA), Queensland. The pilot was the only person on board and was not injured. The helicopter was seriously damaged.

While en route from a private helicopter landing site near Springsure to Beauchamp Station, the pilot decided to land to close a gate and identified a suitable landing area located nearby. On approach to the landing area, the helicopter made an uncommanded turn to the right; the pilot immediately applied left pedal and forward cyclic to arrest the rotation. The rotation slowed with the helicopter facing downwind. The helicopter contacted the ground and rolled over.

This accident highlights the dramatic and rapid effect that a loss of 'yaw axis' directional control resulting from loss of tail rotor authority (LTA) or loss of tail rotor effectiveness (LTE) can have on helicopters.