On 17 February 2012, at about 1315 Central Standard Time, a Cessna 210, registered VH-RQD (RQD), was backtracking runway 18 for the general aviation parking area at Darwin airport, Northern Territory.  At the same time, a Cessna 310, registered VH-XXT (XXT), was holding at taxiway Echo 2 (E2) for an intersection departure from runway 29. 

The surface movement controller instructed RQD to cross runway 29 at about the same time as the aerodrome controller cleared XXT for take-off on runway 29. It was estimated both visually and by radar that XXT then overflew RQD crossing the runway by between 150 ft and 500 ft.

Runway incursions are recognised as an ongoing safety concern for the aviation industry and have been cited in numerous accidents world-wide. They can be the result of many different factors and involve pilots, controllers and vehicle drivers. This incident highlights the need for controllers to remain vigilant in monitoring and scanning the runway, both prior to, and after issuing take-off and runway crossing clearances to pilots.

Aviation Short Investigation Bulletin – Issue 17

What happened

The Australian Transport Safety Bureau (ATSB) was requested by the Civil Aviation Safety Authority (CASA) to assist in the examination of a number of aircraft flight control cable terminal fittings, to identify if they had been affected by stress corrosion cracking (SCC). The terminals had been manufactured from SAE-AISI 303 Se stainless steel (part numbers AN669 and MS21260) and were installed on Piper, Cessna and Beech aircraft. SCC is an environmental failure mechanism resulting from a combination of a susceptible material, applied (or residual) stress and a corrosive environment.

What the ATSB found

While several of the 54 submitted cable terminals showed evidence of surface pitting corrosion, none revealed any evidence of SCC when examined visually and using non-destructive testing techniques.

During the course of the ATSB examinations, CASA received fractured cable terminals from a Piper PA32 and an amateur built aircraft; these fittings were also submitted for examination. The failure mechanism in both cases was confirmed as SCC that had initiated on the external terminal surfaces. The ATSB was also advised of the additional failure of a terminal that was investigated by the New Zealand Civil Aviation Authority. The failure mechanism was also confirmed as SCC, however the cracking had initiated from the internal surface of the swaged terminal sleeve where it was in contact with the wire cable.

What's been done as a result

A number of actions have been taken in Australia and internationally to address the issue of SCC in control cable terminals manufactured from SAE-AISI 303 Se. The latest CASA airworthiness bulletin (AWB 27-001 Revision 3) updated owners on the potential for SCC of flight control cable terminals and urged operators to consider replacing the cables before they reach 15 years in service. A recent Federal Aviation Administration Airworthiness Directive (AD-2013-02-13) required the inspection of the stabilator control system on certain Piper aircraft and replacement of parts as necessary. CASA has also initiated a project that is seeking to amend Civil Aviation Order 100.5, ‘General requirements in respect of maintenance of Australian Aircraft’, to mandate a recurring inspection of terminals manufactured from SAE-AISI 303 Se which have a total time in service of 15 years or greater.

Safety message

The ATSB encourages owners, operators and maintainers of aircraft that may be fitted with cable terminals with part numbers AN669 and MS21260, to familiarise themselves with the issues surrounding terminal fitting corrosion and the associated risks to continued airworthiness. Personnel should familiarise themselves with CASA Airworthiness bulletin, AWB 27-001 and the US National Transportation Safety Board Safety Recommendations A-01-6 through -8 released on April 16, 2001. Both documents highlight the risk to continued safe operation associated with SCC of flight control cable terminals and provide a comprehensive background on the failure mechanism and experiences. The ATSB urges operators to consider replacement of the cables in line with the regulators guidelines, as experience has shown that inspection alone is not a complete defence against SCC failures.

What happened

On 16 February 2012, a Government Aircraft Factory N22C, registered VH‑ATO (ATO), was conducting a survey flight north-east of Melbourne Airport, Victoria when it was involved in two losses of separation with two Boeing 737 aircraft. The 737s, registered VH‑VZA (VZA) and VH‑TJY (TJY), were on approach to runway 27 at Melbourne Airport. All of the aircraft were in receipt of an air traffic control service.

What the ATSB found

Although air traffic control intended that the pilot of ATO should keep his aircraft separate from VZA and TJY using visual observation (visual (pilot) separation), not all the prerequisites for using this separation method were met. As a result, the onus remained on air traffic control to maintain either a vertical separation standard of 1,000 ft or a surveillance separation standard of 3 NM (5.6 km). Losses of separation occurred when separation between ATO and VZA reduced to 1.5 NM (2.8 km) and 300 ft, and between ATO and TJY when separation reduced to 1.7 NM (3.2 km) and 700 ft.

The ATSB also identified that the controller was not aware of how specific aspects of the survey operation were to be conducted and therefore could not be assured that separation would be maintained.

Additionally, the ATSB identified that limited guidance and training was provided to controllers operating outside the towered environment in the application of the visual (pilot) separation standard, increasing the risk of the incorrect application of the standard.

What's been done as a result

In response to these occurrences, Airservices Australia amended the Manual of Air Traffic Services to include a number of factors to be considered by air traffic controllers prior to assigning visual (pilot) separation. In addition, the training package for Melbourne Airport arrivals controllers was reviewed and updated to ensure that visual separation, transfer of separation responsibilities and associated phraseologies were adequately addressed. Finally, the controller checking regime was strengthened to ensure that any identified training and/or knowledge deficiencies in relation to assigning visual separation, and their impact on controller performance, were addressed.

Safety message

The use of visual (pilot) separation transfers responsibility for separation between aircraft operating in controlled airspace from the air traffic controller to the flight crew of one of the aircraft. This occurrence highlights that, for the standard to be effective, all parties must have a shared understanding. Correct application of the visual (pilot) separation standard ensures that all involved flight crew are aware of their responsibility, thereby assuring that aircraft will not come into unsafe proximity.

At about 0615 on 2 February 2012, the 42.7 m passenger ferry Rabaul Queen capsized and sank about 9 nautical miles off the Papua New Guinea (PNG) town of Finschhafen. Two hundred and forty six people were rescued during a search and rescue operation that was coordinated by the PNG Maritime Rescue Coordination Centre and the Australian Rescue Coordination Centre. However, at least 142 people are thought to have died as a result of the sinking.

On 16 February, following a request from the PNG Government, four officials from the Australian Transport Safety Bureau (ATSB) travelled to the PNG capital Port Moresby to offer initial advice to local authorities in safety aspects of the investigation into the sinking.

From that time until 28 June 2012, two ATSB transport safety investigators provided assistance to the PNG Government's Commission of Inquiry into the sinking of Rabaul Queen in accordance with Section 12AA (2)(a)(iii) of the Transport Safety Investigation Act 2003. This part of the ATSB’s governing legislation provides for cooperation with authorities in other countries in the interest of transport safety.

The Commission of Inquiry’s final report was presented to the Prime Minister of PNG on 28 June 2012 and it was subsequently tabled in parliament on 5 September 2012. Information, including the Commission of Inquiry's terms of reference, hearing transcripts and final report can be found at: http://www.coi.gov.pg/rabaulqueen.html

What happened

On 15 February 2012, a Toll Aviation Pty Ltd Fairchild Industries Inc SA227 Metro III aircraft, registered VH-UZA, was being operated on a post-maintenance acceptance flight in the circuit at Brisbane Airport, Queensland with two crew on board. On selection of the landing gear handle to the down position, the landing gear would not extend. After unsuccessful attempts to extend the landing gear in both normal and emergency gear extension modes, the crew decided to conduct a wheels-up landing. At about 0230 Eastern Standard Time the aircraft landed along the centreline of runway 19. The crew evacuated without injury and the aircraft sustained substantial damage.

What the ATSB found

The ATSB found that an electrical wire to the landing gear selector valve had separated at a connector adjacent to its terminal preventing normal operation of the landing gear to the down position. The investigation also identified an out of rig condition in the landing gear emergency extension system, which prevented correct operation of that system. Factors including the maintenance practices by a number of personnel and inconsistent maintenance documentation contributed to the existence of the defects.

What's been done as a result

The aircraft manufacturer advised that, as a result of this occurrence, re-routing requirements for the landing gear selector valve electrical wiring loom in the Metro aircraft have been distributed to all Metro operators through a Metro Global advisory publication.

The operator carried out a fleet-wide check of the landing gear on its Metro aircraft and rectified any defects found. The operator also re-routed the electrical wiring loom to the landing gear selector valve. In addition, the operator amended the pilot’s quick reference handbook and the Metro phase inspection worksheets and issued an engineering memorandum to all aircraft maintenance personnel detailing the operator’s requirements with regards to following standard procedures and approved data for maintenance tasks.

Safety message

This investigation highlights the importance of operators and approved maintenance organisations having a detailed understanding of the systems installed on the aircraft types that they are authorised to certify and aircraft manufacturers providing clear and concise maintenance procedures in an aircraft’s suite of manuals.

Preliminary report released 9 March 2012

This preliminary report details factual information established in the investigation’s early evidence collection phase and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

At about 1555 Eastern Daylight-saving Time on 4 February 2012, a Robinson R44 Raven II helicopter, registered VH-COK, lifted off from Jaspers Brush Aerodrome, New South Wales for an aerial filming task at Jervis Bay. On board were the pilot and a camera operator.

Soon after lifting off, the pilot's door opened. The helicopter abruptly pitched nose-up and the tailskid struck the ground. The helicopter then abruptly pitched forward and rolled to the right before the main rotor blades struck the ground. A fuel-fed fire started in the vicinity of the fuel tanks and lower mast area. The fuselage then hit the ground. Both occupants were fatally injured, and the helicopter was destroyed.

On 20 December 2010, the manufacturer issued R44 Service Bulletin 78 (SB 78) requiring that R44 helicopters with all-aluminium fuel tanks be retrofitted with bladder-type fuel tanks as soon as practical, but no later than 31 December 2014. At the time of the accident, about 90% of the helicopters originally fitted with all-aluminium fuel tanks, including VH-COK, had not been retrofitted. On 21 February 2012, the manufacturer issued SB 78A that revised the date of compliance to 31 December 2013.

In addition, the manufacturer released SB 82 in respect of the replacement of existing R44 rotor brake switches. The aim of that bulletin was to reduce the chance of the rotor brake switch as a possible ignition source in the event of a fuel leak.

Although the circumstances of this accident are still under investigation, the Australian Transport Safety Bureau has, in the interest of transport safety, issued a Safety Advisory Notice suggesting that operators and owners of R44 helicopters fitted with all-aluminium fuel tanks actively consider replacing those tanks with bladder-type fuel tanks, as detailed in SB 78A as soon as possible. The existence and content of SB 82 is also highlighted.

What happened

On 6 February 2012, the flight crew of an Airbus A320-232, registered VH-JQX, commenced take-off from runway 16R at Sydney Airport, New South Wales. The flight crew consisted of a training captain and a captain under training, who was occupying the left seat and conducting the duties of the captain.

During the take-off, one of the thrust levers was inadvertently moved forward of the required detent, which resulted in a thrust setting reversion to manual mode. The training captain identified the issue and initially made the required standard calls to the captain under training to indicate the issue with the thrust lever.

The training captain then made a call to indicate that the take-off should continue, with maximum thrust selected, and the captain under training began rotating the aircraft below the required rotation speed. At about that time the training captain increased the thrust levers to the maximum thrust setting. After noting the aircraft’s airspeed was below the required rotation speed, the captain under training discontinued the rotation until a suitable airspeed was achieved prior to commencing the climb.

What the ATSB found

The ATSB found that the captain under training misunderstood the command from the training captain, which led to the early rotation. The training captain recognised the thrust lever asymmetry situation, however the captain under training did not, and this resulted in a miscommunication that was not resolved effectively between the crew.

In addition, the captain under training was transitioning from another aircraft type to the A320 and the manual thrust mode on the A320 was consistent with his experience of a normal take-off on the previous aircraft type. This created a level of confusion for the captain under training and made it more difficult for him to recognise the thrust lever asymmetry situation. A situation where one thrust lever is in the detent and the other is not, is indicated to the crew on the flight mode annunciator panel and is only displayed above 100 ft.

What has been done as a result

Jetstar have advised that they have incorporated a module into simulator training for all pilots covering incorrect thrust settings at take-off. They have also released a communication to pilots on the responsibilities of the pilot in command during operational events.

Safety message

This incident highlights the importance of good flight crew communication to ensure a shared understanding of the aircraft’s system status.

On 22 November 2011, during pre-flight performance calculations at Melbourne Airport, the crew of a Qantas Airways Boeing B737-476 aircraft, registered VH-TJL, inadvertently used the full-length runway 16 distance to calculate the take-off performance figures despite planning a runway 16/taxiway Echo intersection departure. Neither crew identified the error, which produced inappropriately high take-off reference speeds. During the take-off run the crew realised there was inaccuracy in the figures and elected to continue the take-off, rotating the aircraft below the calculated rotation speed (V_R). The error was attributed to the Electronic Flight Bag (EFB) menu structure defaulting to the full runway length.

As a result of this incident, Qantas Airlines advised that they have modified the EFB to require a positive selection of the runway length. The application of correct operating data is a foundational and critical element of flight safety, but errors in the calculation, entry and checking of data are not uncommon. The ATSB has published a research report that addresses the issue.

At 1310 Western Standard Time on 25 January 2012, a Bombardier Inc DHC-8-202 (Dash 8), registered VH-ZZI (ZZI), was on descent into Broome Airport. At about 17 NM, the flight crew of ZZI advised Broome Tower that they were descending in response to a Traffic Collision Avoidance System (TCAS) Resolution Advisory (RA) alert.

The first officer on ZZI sighted a Pilatus Aircraft Ltd PC-12/45 (PC12) about 1 NM ahead and reported that it passed about 200 to 300 ft to the right and slightly above them.

The traffic was identified as a PC-12, registered VH-MWO (MWO), that had departed Broome Airport at 1300. The pilot of MWO only became aware of the breakdown of separation after ZZI reported a TCAS Traffic Alert (TA), at which time he observed the Dash 8 on his TCAS, behind and on a reciprocal heading. The pilot did not recall hearing a TCAS audible alert.

Both aircraft were operating under Instrument Flight Rules (IFR) and were within airspace controlled by Broome Tower which utilised procedural separation.

The pilot of MWO had not selected automatic direction finding (ADF) as one of the active navigation aids in the aircraft's Electronic Flight Instrumentation System (EFIS). As a result, upon programming new information into the EFIS after departure, MWO unintentionally deviated from the desired outbound track and conflicted with the inbound track of ZZI.

Following the incident, the operator of MWO checked all aircraft in its fleet to ensure that the audio level of the TCAS could be heard above engine noise and radio traffic. MWO was the only aircraft that required the audio level to be increased.

This incident highlights the need for pilots to cross check aircraft navigation performance to ensure accurate track keeping particularly when operating in a procedural separation environment. The incident also highlighted the need to comply promptly with TCAS advisory alerts.

What happened

At about 1710 on 27 January 2012, a De Havilland Aircraft Pty Ltd DH-82A Tiger Moth aircraft, registered VH-GVA, took off from Maryborough Airport, Victoria, with two people on board.

Immediately after lift-off, the aircraft was observed to have a partial, intermittent power loss. The pilot continued the flight with the aircraft maintaining altitude or climbing slightly. At the upwind end of the runway, the aircraft made a climbing left turn before stalling and descending. The aircraft impacted the ground, and the occupants received fatal injuries.

The aircraft was seriously damaged by the accident forces and post-impact fire.

What the ATSB found

The partial engine power loss was probably a result of a partial blockage of the aircraft’s fuel cock. Although sufficient runway remained ahead to allow a safe landing, the flight was continued under limited power without gaining sufficient height to clear trees beyond the runway. Approaching the trees the aircraft climbed, lost airspeed, stalled and collided with terrain. There would have been a safer outcome had the pilot immediately landed the aircraft straight ahead.

Safety message

This accident illustrates several of the points made in the ATSB’s research report