What happened

On 9 March 2013, two glider clubs were conducting gliding operations at Tocumwal aerodrome, New South Wales. A Grob G103 Twin Astir glider, registered VH‑UIZ (UIZ), was towed airborne, however, after a number of orbits looking for rising air, the pilot of UIZ tracked to return to the circuit and land. A few minutes later, a Cessna 150 registered VH‑ROZ (ROZ), became airborne towing a glider. ROZ and this glider were from one gliding club, UIZ from the other. Following the release, the pilot of ROZ turned left and tracked for a left downwind for runway 36L.

Witnesses on the ground reported hearing both pilots making all necessary CTAF broadcasts.

Just as ROZ touched down on runway 36L, the pilot felt a heavy jolt on the top of the cockpit and simultaneously heard a loud noise. Immediately, he saw the windscreen fill with the underside of a glider. He observed the glider continue down the runway at about 5 to 10 ft above ground level. The pilot was uninjured and, on exiting the aircraft, observed a wheel contact print on the top of the aircraft. The pilot of UIZ was uninjured and landed the glider well down the runway. On exiting the glider, the pilot observed damage on the left wing and fuselage.

As a result of this occurrence, the GFA has advised the ATSB that they will raise awareness of collision risk at non-towered aerodromes with its members through the Gliding Magazine and through its biennial Safety Seminars.

As a result of this occurrence, the operator of the glider tug has advised the ATSB that they are sourcing quotes for the fitment of FLARM collision warning system to their gliders and glider tug aircraft.

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 never assume that an absence of traffic broadcasts means an absence of traffic.

Aviation Short Investigation Bulletin - Issue 19

What happened

In the period 2006 to 2012, the Australian Transport Safety Bureau (ATSB) investigated three fatal accidents involving PZL-Mielec M18 Dromader aircraft. All three investigations identified actual and potential safety issues regarding the operation of M18 Dromader aircraft at take-off weights above 4,200 kg. Although the aircraft were all permitted to operate at increased weights, the ATSB sought an understanding of any common factors across the investigations, and whether there were any implications for the continued safe operation of the type at those increased weights. As a result, the ATSB initiated a safety issues investigation in November 2011 to examine those factors and identify any potential safety issues.

What the ATSB found

The investigation identified several safety issues indirectly arising from the operation of M18 aircraft at increased weights. Though some of these issues were minor in isolation, collectively the increase in risk was more significant and the investigation illustrated the need for careful consideration of potential risks when expanding an aircraft’s role and/or capability.

The investigation established issues regarding the:

• practicality of a 15° bank angle limitation that is imposed at increased weights, which would probably affect or preclude some agricultural operations,
• potential for pilots and operators to apply incorrect operating limitations for flights at some weights under a relevant Supplemental Type Certificate (STC),
• method used to apply service life adjustments required at higher weights,
• risk of aircraft incorporating the STC not being configured to the same standard as the flight test aircraft, and
• risk to operators if they do not recalibrate a hopper sight level gauge when changing the hopper size and/or shape.

What has been done as a result

The owner and developer of the STC reported that they were in the process of amending it and were developing a proposal for Civil Aviation Safety Authority consideration and approval. This proposal would address the maximum bank angle limitation and required aircraft modifications, as well as clarify the applicability of the flight manual limitations and airframe service life adjustment method.

Safety message

The investigation highlights some of the risks involved in increasing an aircraft’s operating weight. The importance of pilots and operators understanding and applying any operating limitations that might accompany an operational enhancement is also highlighted.

Safety summary

What happened

At 0055 on 5 March 2013, Pacific National grain train 9054 derailed at the O’Tooles Road level crossing near Pyramid Hill in northern Victoria. The train derailed about midway through the crossing at pre-existing fractures in one of the rails.

The train comprised three locomotives and 40 loaded grain wagons. Nineteen of the first 20 wagons derailed resulting in severe damage to wagons, a significant loss of grain load and damage to about 270 m of track. The train crew were uninjured.

What the ATSB found

The ATSB found that a small section of one rail had broken away during the passage of the Swan Hill bound passenger service 8045 at about 2240 earlier that night. The fractures in the rail had occurred as a result of the rail’s heavily corroded and wasted condition.

The poor condition of the rail had not been detected by the network manager, V/Line, which had relied on ultrasonic testing to identify rail defects. The track inspection regime did not include sufficient supplementary systems for monitoring the condition of buried track at unsealed level crossings.

The construction method used at unsealed crossings increased the risk of this type of failure. Burying the rail web and foot with road materials increased the potential for corrosion and limited the effectiveness of above-ground visual inspection.

This derailment follows a similar event at Warracknabeal in 2011 that was also investigated. Action taken by the network manager following that event did not fully address the identified limitations of the inspection regime for unsealed level crossings.

What's been done as a result

Following the incident, V/Line examined 13 per cent of unsealed crossings in its network and the results were used to develop recommendations for other unsealed level crossings across the V/Line network. V/Line asset management systems are to be updated with improved maintenance requirements for unsealed crossings, and a review will be undertaken of crossing construction methods to determine whether the existing standard of construction is the most appropriate method. These safety actions are ongoing and their success at reducing risk will depend on the effectiveness of their implementation.

In addition, the effectiveness of ultrasonic inspection of rail at unsealed level crossings has been improved, including the development of additional procedures and training specific to the identification of corroded rail at level crossings. 

Safety message

The design, construction and inspection of level crossings at unsealed roads should ensure that track remains fit-for-purpose throughout the life of the asset. Inspection regimes must ensure that where technologies, such as ultrasonic testing, have identified limitations other measures are in place to identify track degradation.

Safety summary

What happened

At about 0623 on 2 March 2013, Pacific National freight train 9501V, travelling from Appleton Dock to Tottenham Yard, derailed at South Dynon Junction near Melbourne, Victoria. Due to a track closure, the Network Control Officer (NCO) had been routeing all train movements via an alternative route through the South Dynon junction area via the North Dock line, signal DYN114, and 113 points. All of these train movements were standard-gauge trains. The NCO set the same route through South Dynon for train 9501V, a broad-gauge train. However, the route selected was for a standard-gauge train only as it did not contain a broad-gauge rail beyond signal DYN114, other than the 40-metre length leading to its truncation.

Having detected the train as broad-gauge and therefore incompatible with the remainder of the established route, the signal interlocking system prevented signal DYN114 from clearing. Train 9501V stopped at signal DYN114 and, through discussion, both the NCO and the locomotive crew assumed a signal failure. The NCO subsequently issued a verbal authority to the driver to pass signal DYN114. The locomotive crew then proceeded past signal DYN114 for a distance of about 40 m where the broad-gauge rail ended, resulting in train 9501V derailing at low speed.

What the ATSB found

The ATSB found that when the NCO established the route, the train control system provided no indication that sections of it were dual-gauge and sections were single-gauge. When train 9501V approached signal DYN114, there was minimal indication to the NCO that the train gauge and the selected route were incompatible. As the train proceeded past signal DYN114 and 113 points, it derailed because the configuration of the dual-gauge points assembly led to a truncated broad-gauge rail in the selected turnout direction.

The ATSB also found that there were deficiencies and ambiguity in the procedures for authorising movement past signals that display a Stop indication. There were also deficiencies in the route knowledge information provided to drivers and no additional indications to a train driver that the broad-gauge track terminated.

What's been done as a result

ARTC has modified the train control system to alert network control officers when a route is set that is not compatible with the gauge of the train, and has amended processes regarding authorising train movements past signals that are displaying a Stop indication.

Safety message

This report emphasises the need for rail transport operators to provide adequately designed system displays that are not provocative of decision-making error by operators. It also highlights the need for train crew and NCOs to ensure they have considered the possibility that an unexpected Stop indication is not always due to signal failure.

What happened

On 30 January 2013, a Fairchild SA 227AC, registered VH-UUO (UUO), departed Melbourne Airport, Victoria for Launceston Airport, Tasmania on a scheduled freight flight. The pilot was the only person on-board.

The pilot prepared a trim sheet to confirm the weight and balance information for the aircraft, then provided an uplift figure to the freight organisation that prepared a loading plan that they used to load the aircraft.

When the pilot approached the aircraft, the freight had been loaded with all cargo access doors closed and the cargo support strut (tail stand) removed. The pilot completed the pre-flight checks in the cockpit then, removed the wheel chocks and wing tip safety markers and placed them in the main cabin area.

During the take-off, the pilot reported that he needed more forward elevator trim than usual to climb out at a 10 degrees nose-up attitude. The pilot noticed that in straight and level flight, the aircraft had full nose-down trim and the aircraft was flying at a 50 nose-up attitude. When the autopilot was engaged, the pilot reported that the autopilot struggled to maintain straight and level flight and the aircraft ‘porpoised’.

The pilot conducted a normal landing at Launceston and checked the freight located in the nose locker. The pilot estimated that the nose locker contained 35 kg of freight when it should have contained about 100 kg. After off-loading the freight at Launceston, the aircraft was re-loaded for the next flight, to ensure that the aircraft was within the centre of gravity limits.

As a result of this occurrence, the operator has advised the ATSB that they are taking safety action including: develop a plan to provide training for all employees, establish an audit oversight program, establish standard operating procedures for all facets of operation and identify all managers and supervisors that require training or retraining including agents.

Aviation Short Investigation Bulletin Issue 20

What happened

On 24 February 2013, the pilot of a Cessna 206 aircraft, registered VH-TOC (TOC), was conducting a private flight from Lake Nash, Northern Territory, to Mount Isa, Queensland, when the aircraft’s avionics system failed. The pilot commenced the radio failure procedure by squawking the transponder code of 7600 and transmitting blind.

The pilot overflew the Mt Isa Airport to assess the wind conditions and rocked the aircraft’s wings to alert any ground personnel of the communication failure, he then joined the circuit.

At around the same time, the Mount Isa airport safety officer (ASO) was preparing to conduct a runway and lighting inspection. The ASO turned on the vehicle’s radio and lighting. The ASO then activated the pilot activated lighting (PAL) and aerodrome frequency response unit (AFRU) systems.

The ASO broadcast a call on the Mount Isa common traffic advisory frequency (CTAF), advising that the vehicle was entering the runway and conducted a lookout for aircraft. As no response was received or aircraft sighted, the inspection was commenced.

By this time, the pilot of TOC was on the base leg of the circuit for runway 34 and observed a vehicle near the runway 34 threshold. He assumed the vehicle and would exit the runway, leaving the runway clear for him to land. The pilot continued to transmit his intentions blind.

As the pilot commenced the flare, he noticed that the vehicle had not yet vacated the runway. As a result of the vehicle being on the runway, the pilot initiated a go-around.

The aircraft passed 200-300 ft above the vehicle. The ASO heard TOC pass overhead and vacated the runway. The pilot of TOC conducted a second circuit and landed without further incident.

Mount Isa Airport Pty. Ltd. had planned to place yellow and black chequered safety stickers on the side and rear of the vehicle. As a result of this occurrence, that action was immediately implemented.

The need to conduct a go-around may occur at any point in the approach and landing phase, however, the sooner a condition that warrants a go-around is recognised, the safer the manoeuvre will be.

Aviation Short Investigation Bulletin Issue 19

What happened

On 4 January 2013, a Boeing 737-800 registered VH-VUZ, departed Launceston, Tasmania on a scheduled passenger service to Melbourne, Victoria. During departure, the crew selected level change (LVL CHG) as the vertical auto-flight system mode, and a climb speed of 250 kts. The crew intended to switch from LVL CHG mode to vertical navigation (VNAV) mode later during the climb, but inadvertently overlooked that selection.

Had the crew switched to VNAV mode as intended, the aircraft would have accelerated during the climb in accordance with a programmed speed schedule. In LVL CHG mode however, the aircraft climbed at a constant speed of 250 kts until passing about flight level (FL) 260, when the auto-flight system sequenced automatically to continue the climb at a constant Mach 0.62 (which was the Mach Number corresponding to 250 kts when the changeover occurred).

As climb then continued above FL 260 at a constant Mach 0.62, airspeed gradually reduced. The unintended vertical auto-flight mode and the gradual airspeed reduction went unnoticed by the crew until the aircraft was approaching FL 350, when a ‘buffet alert’ caution appeared on the Control Display Unit and the auto-flight system made a small reduction in aircraft pitch attitude. At that moment, the crew noted that the airspeed had reduced to near the top of the amber bar on the airspeed indicator, representing the aircraft minimum manoeuvre airspeed.

In responding to recognition of the minimum manoeuvre airspeed condition, the crew reduced the aircraft pitch attitude to the point that the aircraft entered a shallow descent. Soon after, the crew was able to establish an accelerated climb to the intended cruising level of FL 360. Recorded data indicates that that aircraft reached a minimum speed of 201 kts, about 6 kts below the minimum manoeuvre airspeed at that moment.

The occurrence highlights the importance of consistent attention to auto-flight system modes and aircraft energy state. Since this occurrence, the operator has introduced a procedure requiring the announcement of flight mode annunciation changes. The operator also included mode awareness briefings during a 2013 recurrent training program.

Aviation Short Investigations Bulletin - Issue 30

Safety summary

What happened

On 15 February 2013, the crew of a Super Puma helicopter (VH-BHK) was returning to Barrow Island after conducting some night deck landing practice to an offshore vessel. At about halfway the helicopter entered cloud with severe turbulence and lightning. The crew steered away from Barrow Island and descended to the lowest safe altitude to try and escape the conditions, but after 10 minutes turned back towards the island.

With insufficient fuel to divert to a suitable night landing alternate or to safely conduct a published instrument approach, the crew of the twin-engine helicopter were compelled to shut down an engine to conserve fuel and to descend below the lowest safe altitude in instrument meteorological conditions. The crew eventually descended to 250 ft over water and visual contact was made with lights in vicinity of the island. To minimise distraction and conserve fuel, the crew did not restart the engine and landed in winds gusting to 50 kt. Fuel remaining was 300 lb (170 L), which was less than the stipulated fixed reserve.

What the ATSB found

The ATSB found that the crew departed Barrow Island for the night training flight with sufficient fuel to return and land with standard reserves intact as allowed by the aerodrome forecast, but encountered unforecast severe weather on the return sector that prevented a routine visual or instrument approach.

The validity of the Barrow Island aerodrome forecast had been extended to cover the duration of the flight, but the forecast did not include any reference to severe weather, and was not amended when the adverse trend became evident because the forecaster on duty at the time was unaware of the extended validity.

What's been done as a result

The Bureau of Meteorology compiled a report of the meteorological aspects of the occurrence which recommended the development of a handover checklist to be followed by all forecasters, including the handover of any non-routine forecasts. The report also recommended that all forecasters read the report and sign a reading register to indicate understanding of the importance of handing over critical information.

Safety message

Although a flight plan notification was not required and might not have made a difference in this occurrence, the non-submittal of an instrument flight rules notification to air traffic services was a missed opportunity to receive directed weather hazard alerts and reduce weather-related risk.

What happened

On 22 February 2013, VH-TGY (TGY) and VH‑TZJ (TZJ), departed a private airstrip near Bourke for Rumleigh, New South Wales. Both aircraft were to conduct aerial application (spraying) operations, which was supported by two ground personnel (mixers).

TGY landed at the Rumleigh and the mixers loaded the aircraft’s hopper. TGY departed and commenced spraying operations. Shortly after, TZJ landed at Rumleigh and was loaded. As the take‑off run on the south-eastern runway was commenced, TZJ’s fire-bombing door unexpectedly released and the 2,700 L load was jettisoned onto the ground, contaminating the runway.

About 15 minutes after, TGY landed on the north-west runway. When approaching the runway end, the pilot observed mud spraying up from the aircraft’s wheels. The aircraft then commenced sliding and turning to the left. When the left wheel contacted dry ground, the aircraft swung further left and tipped forward, resulting in the propeller contacting the ground. The aircraft then tipped backwards, and the tail wheel assembly detached. TGY sustained substantial damage.

The pilot of TZJ had attempted to contact the pilot of TGY on a number of occasions, but due to an unserviceable radio in TZJ, the broadcasts were not heard. The mixers elected not to contact TGY as they were of the understanding that he had been advised of the contamination by the pilot of TZJ.

A reliable communications system can assist with improving the overall efficiency and safety of an operation. This incident highlights the impact ineffective two-way communications can have on aircraft operations, and in that case, the need to consider alternative means for warning pilots of potential ground hazards.

Aviation Short Investigation Bulletin - Issue 19

At 1625 on 26 February 2013, the Rescue Coordination Centre (RCC) Australia was advised that Mellum Trader was in need of assistance. The ship had been drifting to the northwest of Broome, Western Australia, while the master waited for the port to re-open following the passing of Cyclone Rusty. However, the cargo had shifted as a result of the ship’s movement in the extreme weather conditions and the ship was now listing heavily.

Air and surface assistance was tasked to the area and the master altered course to minimise the effect of the weather on the ship. When the weather abated, the ship resumed its passage to Broome where it berthed on 1 March.

During the course of the investigation, the ATSB looked at several areas which may have had an influence on the incident, its outcome or have ongoing safety implications. These included:

• tropical cyclone avoidance
• guidance material and management support/resources
• cargo lashing and securing plans and arrangements
• ship stability and ballasting
• passage planning and record keeping
• actions of the master and crew
• effectiveness of the emergency response.

Analysis in these and other areas of investigation revealed no underlying safety issues. Accordingly, the ATSB decided that there was limited potential to enhance transport safety by continuing this investigation, and has elected to discontinue it.