Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the Australian Transport Safety Bureau (ATSB) to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation.
On 23 September 2016, the ATSB commenced an investigation into the descent below segment minimum safe altitude involving Airbus A330-343X, 9M-XXI, near Gold Coast Airport, Queensland, on 11 September 2016.
The aircraft was cleared to conduct a RNAV-Z (GNSS) instrument approach to runway 14 (Figure 1) at Gold Coast Airport in visual meteorological conditions. During the approach, the aircraft was observed to descend below the 1,700 ft segment minimum safe altitude between the instrument approach’s intermediate fix (OOLNI) and a position 2.5 NM from the final approach fix (OOLNF).
The ATSB interviewed the flight crew and also examined the operator’s policies and procedures for the conduct of the RNAV-Z type approach. The flight crew reported that they had briefed the approach. That briefing included identification that the 2.5 NM position was not included in the aircraft’s navigation data base and that there was a segment minimum safe altitude requirement associated with this position.
The approach was flown using the autoflight system in a managed mode. As the aircraft approached the OOLNI, the aircraft was in a shallow descent and the flight crew commenced configuring the aircraft for landing (Figure 2). At OOLNI the aircraft was fully configured for landing and at a speed of 150 kt. As the aircraft passed through OOLNI, the autopilot pitched the aircraft down. The flight crew attempted to recover the speed through the application of speed brake. However this, coupled with the aircraft pitching down, resulted in an increased rate of descent, which in turn led to the penetration of the 1,700 ft segment minimum safe altitude. The aircraft subsequently returned to its targeted flight profile by OOLNF and continued the approach for landing.
Figure 2: The instrument approach vertical profile
Source: Jeppesen
The Flight Crew Training Manual (FCTM) for the A330 stated that the activation of the approach phase will initiate a deceleration towards the approach speed or a speed constraint inserted into the Final Descent Point (FDP). The FDP was defined as the capture point of the final descent segment coded into the navigation data base. The two approach techniques for the final descent segment were the decelerated approach and the early stabilised approach.
For the decelerated approach, the vertical flight profile was managed by the aircraft’s Flight Management Guidance and Envelope System (FMGES) using data in the aircraft’s navigation database, modified as required by the flight crew. This was described as using the autoflight system in a ‘managed mode’. The deceleration profile targeted having the aircraft at 1,000 ft above the landing point, in the landing configuration and at the approach speed. This profile generally equated to the aircraft being configured with the first stage of flap/slat and at the required speed at the FDP. In the discussion on the use of a managed vertical profile for a non-precision approach, the FCTM noted that for some non-precision approaches, ‘the final approach flies an “idle descent” segment from one altitude constraint to another, followed by a level segment’.
The early stabilised approach technique required the flight crew to have the aircraft in the landing configuration and at the approach speed at the FDP. The final descent segment was then flown using a selected vertical profile mode, such as the Flight Path Angle (FPA) mode.
The ATSB obtained the navigation database used by the FMGES for the RNAV-Z (GNSS) Rwy 14 approach. That database included initial (OOLNI) and final (OOLNF) approach fixes and their associated altitude limits, but did not include the point 2.5 NM from OOLNF and its associated segment minimum safe altitude limitation. The database also included a three degree approach profile from the OOLNF, but did not include a three degree profile before OOLNF.
The operator’s investigation into the occurrence identified that, as the three degree glide path started at OOLNF, the aircraft would conduct a stepped descent between OOLNI and OOLNF. The stepped approach profile was reflected by the autopilot pitching the aircraft down as it passed through OOLNI. In a stepped approach, on passing an altitude constrained position (such as OOLNI), the autopilot will fly an idle descent to the new altitude constraint and then fly level until the completion of that segment. The operator also noted that the step down limitation between OOLNI and OOLNF was not coded into the database due to specific coding rules. In response to the occurrence event, the operator custom coded the RNAV-Z (GNSS) Rwy 14 approach to include a 3 degree slope from OOLNI. The operator also issued a memorandum to all pilots requiring all non-precision approaches into Australia to be conducted using the selected vertical guidance Flight Path Angle mode only. Based on this information, the ATSB determined that it was unlikely that further ATSB investigation would identify any systemic safety issues. Consequently, the ATSB has discontinued this investigation.
Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the Australian Transport Safety Bureau (ATSB) to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation.
At about 1000 Western Standard Time on 10 September 2016, an Air Tractor AT-502 aircraft, registered VH‑ULV, was conducting aerial agricultural spraying activities at Salmon Gums, near Esperance, West Australia. During a turn at about 200 ft above the ground, the pilot lost control and the aircraft collided with terrain. The aircraft was substantially damaged and the pilot sustained serious injuries.
Figure 1: VH-ULV showing damage Source: Operator
Preliminary enquiries by the ATSB suggest that the accident was attributable to pilot actions. The ATSB considered it was very unlikely that further investigation would uncover any systemic safety issues. The ATSB has discontinued the investigation.
On 18 September 2016, at about 1355 Eastern Standard Time EST, the pilot of a Robinson R22 helicopter, registered VH-PFX, commenced aerial mustering on a property about 15 km south of Coen, Queensland.
After successfully mustering one mob of cattle into a yard, the pilot started moving a second mob towards the north. The cattle started to move west instead of north, so the pilot descended closer to the cattle to encourage them to turn.
At about 1415, the helicopter was about 10 ft above the ground, at an airspeed of 40 to 50 kt, when a cow with long horns charged and reared up at the helicopter. The cow’s horn went over the right skid of the helicopter, trapping the skid underneath it. The pilot applied full left cyclic and raised the collective, but the helicopter rolled to the right. The main rotor blade struck the ground and the helicopter collided with the ground and slid about 10 m along a dirt road.
As the helicopter slid along the ground, it caught fire. The pilot exited with minor injuries and the helicopter was destroyed.
Aerial mustering, as with other low-flying operations, carries an inherent level of risk. At low level there is limited opportunity to react and respond to an abnormal situation.
On 18 September 2016, at about 1355 Eastern Standard Time (EST), the pilot of a Robinson R22 helicopter, registered VH-PFX, commenced aerial mustering on a property about 15 km south of Coen, Queensland.
After successfully mustering one mob of cattle into a yard, the pilot started moving a second mob towards the north. The cattle started to move west instead of north, so the pilot descended closer to the cattle to encourage them to turn.
At about 1415, the helicopter was about 10 ft above the ground, at an airspeed of 40 to 50 kt, when a cow with long horns charged and reared up at the helicopter. The cow’s horn went over the right skid of the helicopter, trapping the skid underneath it. The pilot applied full left cyclic[1] and raised the collective[2], but the helicopter rolled to the right. The main rotor blade struck the ground and the helicopter collided with the ground and slid about 10 m along a dirt road.
As the helicopter slid along the ground, it caught fire. The pilot exited with minor injuries and the helicopter was destroyed (Figure 1).
Figure 1: Accident site showing VH-PFX destroyed by post-impact fire
Source: Queensland Police
Pilot comments
Normally, the helicopter can remain at a higher altitude and mustering will still be effective as the noise moves the cattle in the intended direction. Very occasionally, when the area is clear, the only way to move the cattle is to get down low.
Bladder-type fuel tanks
In July 2014, the Civil Aviation Safety Authority’s (CASA) monthly update, the CASA Briefing included the section ‘R22 operators urged to fit new fuel tanks’. CASA strongly recommended operators of R22 helicopters to install modified fuel tanks as early as possible. This was in response to Robinson Helicopter CompanyR22 Service bulletin SB-109, which required R22 helicopters with aluminium fuel tanks to be retrofitted with bladder-type tanks to improve the fuel system’s resistance to a post-accident fuel leak. The retrofit was to be completed as soon as practical, but no later than the next 2,200-hour overhaul or 12-year inspection.
VH-PFX was not fitted with bladder fuel tanks. Although the bladder tanks could have been fitted at any time, as the aircraft had not yet reached the 2,200-hour overhaul or 12-year inspection period, it was not yet required to be fitted with bladder fuel tanks.
ATSB comment
Aerial mustering, as with other low-flying operations, carries an inherent level of risk. Elevated awareness and vigilance is necessary to fly an aircraft safely, monitor for the effects of environmental conditions such as wind direction and strength, and to scan for and avoid obstacles and other hazards. Operating at the height of the animals while mustering introduces additional risk as animals can act unpredictably, and should only be done as a last resort. At low level there is limited opportunity to react and respond to an abnormal situation.
Purpose of safety investigations
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
Creative Commons licence
With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
On 8 September 2016, at about 1900 Eastern Standard Time, an Airbus A320-232 aircraft, registered VH-VFN, was being loaded at Sydney Airport, New South Wales, to operate Jetstar flight JQ820 from Sydney to Brisbane, Queensland.
The leading hand assigned to loading the aircraft had received the deadload weight statement (DWS) for the cargo from the cargo terminal operator (CTO), and printed out a copy to refer to while loading the aircraft. The DWS listed three containers of freight and the CTO had previously delivered three containers to the loading bay from their facility. The leading hand checked the containers with those listed on the DWS. Two of the three listed containers were correct, however, the third was listed on the DWS with number 4183 and a gross weight of 240 kg, while the container on the bay was number 1483, which was subsequently found to have had a gross weight of 900 kg.
The container card associated with, and attached to the container also had number 4183 on it. The leading hand assumed that the freight handler had inadvertently transposed the first two digits of the container number from 14 to 41, entered that onto the card and transferred the error onto the DWS. The leading hand therefore amended the card and the DWS with the actual number of the container (1483), and entered that container number onto the underfloor load advice (ULA) as it was loaded onto the aircraft.
At about 1915, the leading hand completed loading the aircraft and took the paperwork, including the DWS and ULA, to the flight deck. The captain sighted the amendments and the leading hand affirmed, as they believed at the time, that the weight was correct and the container number was now correct on the DWS and ULA.
The aircraft departed on time at about 1925. The flight crew were not aware of the discrepancy during the flight and did not encounter any handling or control issues on take-off or receive any abnormal indications.
This incident highlights how being service oriented to increase efficiency can inadvertently bypass safety-related risk controls.
On 8 September 2016, at about 1900 Eastern Standard Time (EST), an Airbus A320-232 aircraft, registered VH-VFN, was being loaded at Sydney Airport, New South Wales, to operate Jetstar flight JQ820 from Sydney to Brisbane, Queensland.
The leading hand assigned to loading the aircraft had received the deadload weight statement[1] (DWS) for the cargo from the cargo terminal operator (CTO), and printed out a copy to refer to while loading the aircraft. The DWS listed three containers of freight, which the leading hand reported was usually loaded onto the aircraft before the passenger bags. The CTO had previously delivered the three containers to the loading bay from their facility. The leading hand checked the containers with those listed on the DWS – crosschecking the container numbers and the flight details, and confirming that the sum of the weight of the three containers corresponded to the total gross weight on the DWS. Two of the three listed containers were correct, however, the third was listed on the DWS with number 4183 and a gross weight of 240 kg, while the container on the bay was number 1483 (Figure 1), which was subsequently found to have had a gross weight of 900 kg.
Figure 1: Container AKH 1483 JQ
Source: Jetstar
The container card associated with, and attached to the container also had number 4183 on it (Figure 2). The leading hand assumed that the freight handler had inadvertently transposed the first two digits of the container number from 14 to 41, entered that onto the card and transferred the error onto the DWS. The leading hand therefore amended the card and the DWS with the actual number of the container (1483), and entered that container number onto the underfloor load advice (ULA) as it was loaded onto the aircraft (Figure 3).
The leading hand supervised the loading of the three containers and the passengers’ bags onto the aircraft and completed filling out the ULA. Container 1483 was loaded into position 32 (see Underfloor load advice), which was close to the aircraft’s centre of gravity.
Figure 2: Container card
Source: Jetstar
Figure 3: Extract of the underfloor load advice
Source: Jetstar
At about 1915, the leading hand completed loading the aircraft and took the paperwork, including the DWS and ULA, to the flight deck. The captain sighted the amendments and the leading hand explained that they had amended the container number because the digits had been mixed up. The captain said they would accept the paperwork if the leading hand was sure the contents of the container was the same as the container listed on the DWS. The leading hand affirmed, as they believed at the time, that the weight was correct and the container number was now correct on the DWS and ULA.
The flight crew then entered the data into the loading program and crosschecked it. The data was then used to generate the take-off data including reference speeds and trim settings based on the weights provided on the DWS. The crew then entered the performance data into the aircraft’s flight management and guidance system.
The aircraft departed on time at about 1925. The flight crew were not aware of the discrepancy during the flight and did not encounter any handling or control issues on take-off or receive any abnormal indications.
Subsequent investigation revealed that the incorrect container was delivered for loading; the CTO had delivered container 1483 (which weighed 900 kg) instead of 4183 (which weighed 240 kg).
Freight management procedures
The aircraft operator’s procedures included that if the DWS was incorrect, then the leading hand was to ‘offload’ the freight – that is, not load it onto the aircraft and remove it from the DWS, irrespective of how the incorrect container arrived at the bay.
Leading hand’s comments
Generally, if there is a discrepancy between the freight and the DWS, the leading hand commented that they would cease loading, go to the office and give the CTO a call. They would then ask the team to email a new DWS and bring a new container card to the loading bay. In this event, time did not permit the normal process to be followed, due to the short turnaround time for the aircraft. In addition, as it was the last Brisbane flight of the day, they were trying to ensure the cargo would be loaded if possible. The leading hand also commented that in their experience, it was not uncommon to have discrepancies on the DWS, including errors in the weights. The leading hand assessed that this had just been a simple transcription error, and changed the numbers.
The leading hand had not been to the CTO facility and was not certain as to how the container card and DWS were compiled. However, the leading hand was experienced in operations in the bag room, where the bags were loaded into containers. The loader would then fill out the container card including the container number and the number of bags loaded into the container. The leading hand commented that transcription errors sometimes occurred in that process, resulting in the incorrect number on the container card. The leading hand would then amend the card to reflect the actual (and correct) container number.
The leading hand subsequently found that the CTO did not operate in a similar way to the bag room. On this occasion, container 4183 with 240 kg of freight was scheduled to be loaded onto JQ820, but the incorrect container was delivered to the bay. The leading hand was advised during a post-incident discussion, that the container numbers and corresponding cargo are entered into a database at the CTO and the container numbers on the DWS would therefore be correct.
The leading hand stated that they would only open up the containers to check the contents if there were dangerous goods manifested in the contents, to check for spills or leakages, or if some contents were insecure. Otherwise, once the container is delivered to the bay from the freight shed, there is no confirmation of its contents and no ability to check the weight of the container.
Captain’s comments
The captain commented that it is necessary for the leading hand to be able to amend the ULA, which is a Jetstar document. However, the DWS is not a Jetstar-generated document. If there was a Jetstar procedure that did not allow amendments to the DWS (and a new one was required from the CTO whenever a change was deemed to be necessary), that may prompt the CTO to review the DWS details. Such a review may identify any discrepancies such as an incorrect container. This would provide an additional defence against an incident of this nature.
The aircraft operator responded to the comment, advising that the operations manual stated that ‘all changes to the DWS must be completed by the cargo terminal operator (CTO)’.
The captain was not required to sign the ULA, unlike the Notification to the Captain (NOTOC) – which contains information about dangerous goods. The captain commented that ULAs were frequently amended, and if the leading hand amends them on the flight deck, they then initial the change.
The leading hand is a trusted member of the team; the captain delegates responsibility for the loading of the aircraft to them. If there are any issues with the loadsheets, the flight crew clarify them with the leading hand. The flight crew can also contact the ground operations controller (GOC) if there are any issues, but the GOC will refer the crew to the leading hand for questions regarding the underfloor load.
The captain accepted the amendment to the DWS based on the leading hand’s confirmation that the correct container weighing 240 kg had been loaded onto the aircraft. The captain then entered that weight into the loading program, an iPad application ‘Jetload’, which was used to generate the aircraft’s performance data.
The captain commented that the Jetload program is very robust and is designed around ease of use. It prevents crew making a basic input error because there is a crosscheck. If there is a mismatch, it will not proceed to the next screen. The data then goes into the Airbus fly smart program along with the environmental and aircraft data, and generates the V speeds[2] and flex temperature for take-off. While the system is robust, it depends on the correct data being provided on the DWS and ULA. Offloading freight or bags is easy to do with the program and only takes 5–8 minutes for the leading hand to action and the crew to amend the data.
Deadload weight statement
The deadload weight statement (Figure 4) was generated by the freight shed at 1824 and the loading details specified three unit load device (ULD, or container) items: AKH4183JQ gross weight 240 kg, AKH4297JQ 300 kg and AKH1583JQ 115 kg, all destined for Brisbane with a total ULD weight of 655 kg.
Figure 4: Extract of the deadload weight statement
Source: Jetstar
Effect on the aircraft
The actual container loaded onto the aircraft weighed 660 kg more than the 240 kg entered into the loading program, and was loaded close to the aircraft’s centre of gravity. The trim setting used for the take-off was the same as would have been used if the actual container weight and position had been entered and the derived V speeds were within 1 kt and the flex temperature within 1 °C of those generated based on the actual aircraft take-off weight. There was no effect on the aircraft performance or handling and no issues or abnormal indications were identified by the flight crew.
Based on the weights listed on the DWS, the leading hand commented that they could have loaded any of the three containers into the forward compartment of the aircraft, but elected to load container 4297 with a gross weight of 300 kg for position 11 (Figure 3) and fortuitously elected to load 1483 close to the centre of gravity.
Safety analysis
The aircraft operator advised that a member of the freight company misread the digits on the container (confusing 1483 for 4183) and transported it to the incorrect bay while delivering the correct DWS and container card.
The leading hand (incorrectly) assumed the freight container (1483) was the correct container to be loaded, but that the container number on the container card and DWS (4183) had been entered incorrectly (due to a transcription error). Although the leading hand could have requested a new printed DWS and container card, due to the combination of the limited turnaround time available and the concern to ensure the freight made it to the destination that night, the leading hand instead ‘corrected’ the numbers with a pen so they matched the number on the container. This resulted in a lost opportunity for the leading hand’s incorrect assumption to be identified. Similarly, although the captain could see there was a discrepancy, they accepted the hand-written amendment to the DWS based on the leading hand’s assurance that the correct container been loaded onto the aircraft.
Findings
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
An incorrect container was delivered to the ramp by the cargo terminal operator, probably because the cargo terminal operator crew misread the similar container numbers.
The short turnaround time combined with this being the last flight to Brisbane that night, along with the assumption there was a transcription error, resulted in the leading hand not requesting a new deadload weight statement and container card, and loading the incorrect container on the aircraft.
Due to the leading hand's assurance, the captain accepted the hand-written amendment to the deadload weight statement.
Although the actual take-off weight was about 660 kg more than the calculated take-off weight, as the container was loaded close to the aircraft’s centre of gravity, there was no effect on the aircraft performance or handling.
Safety action
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.
Aircraft operator
As a result of this occurrence, the aircraft operator has advised the ATSB that they are taking the following safety actions:
Reminder to ground staff
Ground crew have been reminded to offload any freight where there is a discrepancy in the paperwork.
Safety message
The procedure published by the aircraft operator was to offload freight if a discrepancy existed. The leading hand thought it was a simple typographical error and amended the associated paperwork. Their intention was to facilitate loading the freight if at all possible, rather than offload it and leave it overnight for the next shift to deal with. This incident highlights how being service oriented to increase efficiency can inadvertently bypass safety-related risk controls.
Purpose of safety investigations
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
Creative Commons licence
With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
On 9 September 2016, at about 0005 Eastern Standard Time (EST), an AirAsia X Airbus A330-343X, registered 9M-XXK (XXK) pushed back[1] from gate D12 to disconnect point S7 (Figure 1) at Melbourne Airport, Victoria, to operate scheduled passenger flight D7213 to Kuala Lumpur, Malaysia. Although it was night-time, the apron was well lit by flood lights.
The aircraft maintenance engineer (AME) conducting the pushback was provided by a contracted company, the tug and tug driver were provided by a third company. Prior to commencing the pushback, the AME installed the nose gear steering bypass pin,[2] connected the tow bar to both the aircraft nose landing gear and the tug. During the pushback, as the tug moved the aircraft, the AME was seated in the tug. The AME was in continuous communication with the flight crew using a headset connected directly through a headset jack to the cockpit. During the pushback, the flight crew started one engine. After reaching disconnect point S7, the flight crew applied the park brake and started the second engine.
At 0008, after both engines were started, the AME disconnected the headset and tow bar from both the aircraft and the tug, the AME also removed the bypass pin. The tug driver turned the tug around to allow the AME to attach the tow bar to the rear of the tug. The tug driver then moved the tug and tow bar to a position forward of the aircraft’s right engine and visible to the first officer (Figure 2). The AME then walked to a position in front of the tug, and displayed the bypass pin to the first officer. The AME received a hand signal from the first officer confirming the first officer had sighted the bypass pin. Sighting the bypass pin was the final item on the flight crew’s after start checklist. The flight crew then contacted ATC and obtained a taxi clearance.
At 0009, the first officer confirmed to the captain that the AME and tug were clear, the captain then began to taxi. At this time, the AME was walking towards the left side of the tug, which remained parked forward of the aircraft’s right engine and wing. As the AME walked, they detected the aircraft’s taxi light illuminate and the aircraft begin to move. The AME then ran toward the tug door and alerted the tug driver to the aircraft movement.
Video footage of the incident shows the tug driver taking action to avoid a collision with the taxiing aircraft.
The flight departed without further incident.
Figure 2: Positions at commencement of aircraft taxi
Source: Melbourne Airport, modified by ATSB
Flight crew procedures
The flight crew procedures included the following steps:
After the pushback and engine start sequence is complete, the bypass pin must be sighted.
Once taxi clearance is obtained, the flight crew shall ensure both sides of the aircraft are clear prior to taxi.
Flight crew comments
The flight crew of XXK provided the following comments:
Both flight crew interpreted the AME displaying the bypass pin as meaning the tug and AME were clear, and it was safe to commence taxi.
The flight crew assumed that ATC providing the taxi clearance meant that ATC had confirmed the tug was clear of the aircraft.
The first officer observed the tug and AME to the right of the aircraft and assessed that they were clear of the right engine.
Aircraft maintenance provider procedures
The ground handling procedures include the following steps:
Once the tow bar is connected to the tow vehicle (after being disconnected from the aircraft), the tow vehicle must move away to an area that is visible to the flight crew.
At a suitable and safe distance from the aircraft, (the AME must) hold up the bypass pin to provide visual confirmation that it has been removed to the flight crew and give a ‘thumbs up’ signal indicating ‘clearance to proceed’. Once acknowledged by the flight crew, move away from the aircraft to a safe distance for the aircraft to taxi.
AME and tug driver comments
The tug driver and AME both commented that they expected the aircraft to remain stationary until they had moved clear of the S7 disconnect point boundary.
Airservices Australia safety bulletin
The AME and captain commented that they expected air traffic control (ATC) to confirm that the tug was clear of the aircraft and disconnect point S7 prior to providing a taxi clearance.
In 2015, ATC provider, Airservices Australia, identified some misinterpretation among pilots, airside drivers and ground crew regarding the responsibilities for collision avoidance on aerodrome movement areas and the services ATC provide to aircraft and/or vehicles operating on these areas. In response, on 12 November 2015, Airservices Australia released an Aeronautical Information Circular AIC (H32/15) and subsequently in 15 March 2016, this information was released as a safety bulletin, Safety of ground movement on a controlled aerodrome. The bulletin had been provided to the operators involved in this incident.
The bulletin contains the following information regarding operations on the apron and push-back approvals:
The pilot in command (with any assisting ground personnel) is responsible for avoiding collision on the apron. ATC push-back approvals and taxi clearances are only to regulate entrance to, and movement on, the taxiways and do not relate to movement on the apron areas.
When ATC issue approval for push-back or taxi clearance, they will only provide information about relevant known aircraft moving on the same apron. This information may be incomplete as ATC has limited knowledge (or visibility) of movements on the apron. Pilots must also obtain traffic information from assisting ground personnel and, where available, the apron service which may be established as a discrete service at some locations.
Safety analysis
The flight crew interpreted the AME showing the bypass pin at the end of the pushback sequence as notification that all vehicles and equipment were clear of the aircraft and it was safe to commence taxi. The ground crew expected that the flight crew would commence taxi only after all personnel and equipment had crossed the line demarcating the boundary of the S7 disconnect point. Both the flight crew and AME expected that the aircraft would not receive a clearance to taxi until ATC had confirmed that the tug and AME were clear. The misunderstandings by the parties involved during this sequence likely led to incorrect expectations of when the aircraft would begin taxi and the aircraft beginning to taxi prior to the tug moving clear.
The flight crew procedures required the flight crew to visually confirm that all ground equipment was clear of the aircraft prior to taxi. The first officer assessed that the tug and tow bar were clear of the right engine when they were not, although their perception may have been influenced by an expectation of them being clear given the communications with the AME and ATC providing taxi clearance.
Findings
This finding should not be read as apportioning blame or liability to any particular organisation or individual.
The flight crew and ground crew had differing understandings of procedures. These differing understandings led to different expectations of when the aircraft would commence taxi which resulted in the near collision.
The first officer incorrectly assessed the distance of the tug from the aircraft.
Safety message
Ground handling of large aircraft presents many safety risks and requires many separate operators to work closely together. Effective teamwork ensures safe and efficient ground operations.
This incident highlights the importance of separate operators working closely together and having procedures which are well harmonised. It is also important that these procedures are well understood and practiced by all individuals involved from the different operators to ensure all parties understand their role but also how their role interacts with other parties.
Also highlighted, is the importance of understanding the services provided by ATC. ATC provide separation between aircraft, personnel and equipment operating on manoeuvring areas. ATC do not separate aircraft from tugs and other ground personnel on apron areas such as disconnect point S7.
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
Creative Commons licence
With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
On 11 September 2016, at about 1000 Eastern Standard Time, a Jabiru SP500 aircraft registered 19-5503, departed Caboolture Airfield, Queensland (Qld), for a flight to Boonah Airfield, Qld. The pilot was the only person on board.
As the aircraft approached Boonah Airfield, the pilot observed large white crosses on the runway indicating the airfield was closed. The pilot elected to return to Caboolture and applied engine power to climb to cruise altitude.
At about 1055, the aircraft climbed to the north of Boonah. At a height of about 1,000 ft above ground level, the pilot noticed the engine RPM reducing and applied full throttle. At the same time, the pilot observed a low and fluctuating engine oil pressure indication. Within seconds, the engine failed and the propeller stopped rotating.
The pilot identified a paddock to the north of their position as suitable for a forced landing. They manoeuvred the aircraft to conduct a forced landing into the paddock. The pilot ensured that turns made during the forced landing were not tight and of low bank angle to avoid an aerodynamic stall. Late in the ground roll, the nose wheel dug into the soft surface, the aircraft tipped onto its nose and the right wingtip struck the ground. The aircraft then stopped and settled onto its wheels. The pilot was not injured and the aircraft sustained minor damage.
This incident is a good example of the effect an in-flight engine failure at a low altitude has on the time available to manage that failure and identify a suitable forced landing area.
On 11 September 2016, at about 1000 Eastern Standard Time (EST), a Jabiru SP500 aircraft registered 19-5503 (5503), departed Caboolture Airfield, Queensland (Qld), for a flight to Boonah Airfield, Qld. The pilot was the only person on board.
As the aircraft approached Boonah Airfield, the pilot observed large white crosses on the runway indicating the airfield was closed. The pilot elected to return to Caboolture and applied engine power to climb to cruise altitude.
At about 1055, the aircraft climbed to the north of Boonah. At a height of about 1,000 ft above ground level, the pilot noticed the engine RPM reducing and applied full throttle. At the same time, the pilot observed a low and fluctuating engine oil pressure indication. Within seconds, the engine failed and the propeller stopped rotating. The pilot broadcast a MAYDAY[1] call on the Amberley common traffic advisory frequency. Air traffic control staff at RAAF Base Amberley received the MAYDAY broadcast and initiated an emergency response.
The pilot identified a paddock to the north of their position as suitable for a forced landing. They manoeuvred the aircraft to conduct a forced landing into the paddock (Figure 1). The pilot ensured that turns made during the forced landing were not tight and of low bank angle to avoid an aerodynamic stall. Late in the ground roll, the nose wheel dug into the soft surface (Figure 2), the aircraft tipped onto its nose and the right wingtip struck the ground. The aircraft then stopped and settled onto its wheels. The pilot was not injured, and the aircraft sustained minor damage.
Figure 1: 19-5503 after the forced landing
Source: Pilot
Figure 2: 19-5503 after the forced landing
Source: Pilot
Engineering details and examination
5503 is an owner built and maintained aircraft. The engine fitted to 5503 was manufactured in 2001.
A post incident examination of the engine found the engine oil pump drive had failed.
Due to the limited scope of this investigation a post incident engineering examination was not conducted. The cause of the oil pump drive failure was not determined.
Previous occurrences
Jabiru advised that they are aware of one previous oil pump drive failure. In the previous occurrence the manufacturer found the engine maintainer had tightened the oil pump housing bolts (Figure 3) unevenly.
The Jabiru engine overhaul manual part 7.8.17 contains the following guidance on this part of the engine assembly:
Fit the outer pump housing over the gears and insert & hand tighten the retaining cap screws. Use Loctite 243 on the threads and ensure the Jabiru bird is oriented correctly.
While the housing is still loosely held to the engine, rotate the crankshaft through at least 2 full revolutions. This turns the cam and allows the oil pump to find its preferred position. The housing can now be tightened to the value given in Table 9.[2] Failure to turn the engine can result in the oil pump being offset from the cam axis – this applies side loads to the cam and can eventually crack it or break the tip off altogether.
Figure 3: Oil Pump Housing (not incident engine)
Source: Jabiru
ATSB comment
In December 2014, the Civil Aviation Safety Authority (CASA) introduced instrument 294/14 imposing operation limitations on aircraft fitted with Jabiru engines. In July 2015, this instrument expired and was replaced by instrument 102/15.
The engine fitted to the aircraft was a Generation 1[3] engine. The pilot reported that the engine was maintained in accordance with Jabiru directions and complied with all Service Bulletins and Service Letters.
The ATSB determined that the operational restrictions imposed by instrument 65/16 did not apply to this aircraft.
Findings
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
The oil pump drive failed leading to engine failure and forced landing.
The soft surface of the paddock used for the forced landing resulted in damage to the landing gear.
Safety message
This incident is a good example of the effect an in-flight engine failure at a low altitude has on the time available to manage that failure and identify a suitable forced landing area.
The booklet shows that you can prevent or significantly minimise the risk of damage following a partial or complete engine power loss by using the strategies below:
Pre-flight decision making and planning for emergencies and abnormal situations for the particular aerodrome
conducting a thorough pre-flight and engine ground run to reduce the risk of a partial power loss occurring
taking positive action and maintaining aircraft control either when turning back to the aerodrome or conducting a forced landing until on the ground, while being aware of flare energy and aircraft stall speeds.
Purpose of safety investigations
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
Creative Commons licence
With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
On 11 September 2016, the pilot of a Cessna 172RG, registered VH-MKG (MKG), was observed moving the aircraft out of a hangar at Parafield Airport. The aircraft was positioned on the apron in front of this hangar. The pilot then hand swung the propeller to start the engine, with no one at the aircraft controls. Following the hand start, the uncontrolled aircraft taxied a short distance before colliding with a parked Piper PA-32 Saratoga. Although not struck directly by the propeller, the pilot was fatally injured either by being struck by the aircraft or in the subsequent fall as the aircraft taxied away. The pilot's dog was unsecured in the aircraft.
What the ATSB found
The ATSB found that the battery installed in MKG had insufficient charge to start the engine, and that the pilot started the engine by hand swinging the propeller. The aircraft was not adequately secured during the hand start, resulting in fatal injuries to the pilot and damage to another aircraft when it taxied without pilot control.
Safety message
Hand swinging an aircraft propeller is recognised across the aviation industry as a hazardous procedure. Although hand swinging is permitted under the civil aviation regulations, it should only be undertaken when no other alternatives exist to start the aircraft engine and all necessary precautions have been taken to mitigate the hazards.
Additionally, unrestrained animals in the aircraft cabin have the potential to adversely affect safety during aircraft operations.
Final position of VH-MKG against the Saratoga
Source: ATSB
The occurrence
At approximately 1300 Central Standard Time[1] on Sunday 11 September 2016, the owner/pilot (pilot) of a Cessna 172RG aircraft, registered VH-MKG (MKG), arrived at Parafield Airport. MKG was located in a hangar on the aerodrome, where the pilot was employed on a contract basis as a check and ferry pilot and aircraft maintenance engineer.
The ATSB was advised that the pilot had been conducting part of a 100 hour inspection, and other scheduled maintenance, on MKG throughout the weekend. The battery installed in MKG had reportedly been on charge during this maintenance.
At around 1600, witnesses reported seeing the pilot manually reposition MKG outside of the hangar. The aircraft was parked, facing approximately south-west, into the wind. The witnesses observed an initial pull through of the propeller by the pilot, before the pilot returned to the cockpit area for a short time.
The pilot then returned to the front of the aircraft and hand swung the propeller for a second time, resulting in the aircraft engine starting. MKG then taxied without pilot control, turning approximately 45 degrees on a left arc, before colliding with a Piper PA-32 Saratoga, registered VH-HYM, that was parked on the apron, approximately 35m from MKG.
Throughout the engine start and uncontrolled taxi, the pilot avoided being struck directly by the propeller. However, possibly in an attempt to re-enter the cockpit to regain control of the aircraft, the pilot's fatal injuries likely resulted either from being struck by MKG as it taxied or in the subsequent fall.[2]
The impact of the collision pushed the Saratoga about 10m from its parked location. Both aircraft came to rest approximately parallel to each other, facing in opposite directions, with MKG's propeller embedded in the underside of the Saratoga's left wing. The nose cowl of MKG was also wedged under the Saratoga's wing, lifting its left main wheel clear of the ground.
The pilot's dog was found unrestrained in the aircraft cabin and was removed by emergency responders approximately 90 minutes after the accident.
Figure 1: The approximate initial and final positions of VH-MKG and VH-HYM, and the approximate track of MKG. Inset shows the final position viewed from behind MKG
Source: Google Earth, annotated by ATSB.
Starting procedures
The starting procedures for normal operations were contained in the pilot operating handbook (POH) for the Cessna 172RG. It included a checklist of actions to be taken before starting the engine and a starting engine checklist.
In normal operations, the aircraft electrical system was used to start the engine. This required the battery to have sufficient charge to engage the starter motor. Although the battery had been on charge the preceding day while maintenance was undertaken, it was not capable of maintaining sufficient charge to start the engine.
The aircraft was equipped with a ground service port where a ground power unit (GPU) could be connected. The service manual indicated a GPU was intended as a power source for prolonged ground maintenance requiring the use of electrical power. It also indicated, without restricting it to these conditions, that it could be used for cold weather starting. A GPU was available in the hangar where the aircraft was located.
Hand starting procedures
There were no specific procedures to hand start MKG. Civil Aviation Regulation 231 - Manipulation of propeller (CAR 231) permitted the pilot in command to hand swing a propeller to start the engine, provided no assistance was readily available, no passengers were on board the aircraft and adequate provision was made to prevent the aircraft moving forward.
Generic guidance on hand swinging a propeller, published by the Civil Aviation Safety Authority (CASA), the US Federal Aviation Administration (FAA) and various pilot forums, covered topics including:
deciding to hand start
positioning the aircraft
securing the aircraft
setting the engine controls
having assistance.
While CAR 231 permitted hand swinging, the guidance available highlighted the increased risk associated with this starting method, and that it should be considered an emergency procedure, used only when absolutely necessary.[3]
The aircraft was positioned appropriately according to the guidance, outside of the hangar, on firm, flat, level ground, with no obstacles directly ahead.
The guidance advised that:
chocks of an appropriate size and material should be applied to both main wheels
the aircraft should be tied down adequately, using an appropriate restraint
the brakes should be set
the fuel system and engine controls set for a normal start.
CAR 231 requires the person manipulating the propeller to know the correct starting procedure for the aircraft. Additionally, it allows for assistance to be provided by having a qualified person at the controls of the aircraft, if a suitably qualified person is available. The FAA handbook noted that 'the procedure should never be attempted alone.'[4]
Securing the aircraft
Wheel Chocks
A single set of small wooden chocks were located about 15m from the hangar doors, in the approximate area MKG was positioned prior to start-up. The distance between the chocks was consistent with both the nose and main wheels of MKG, with a small gap. It was probable that this gap resulted from forward chock sliding along the ground a short distance as the aircraft rolled over it. A set of aircraft chocks consisting of two aluminium angles connected by a chain were located in the aircraft.
Brake system
The aircraft had a single disc, hydraulically actuated brake on each main landing gear wheel. The brakes were operated by applying pressure to the top of the rudder pedals. When the aircraft was parked, both main wheel brakes were able to be set by using the parking brake. The POH instructed that 'to apply the parking brake, set the brakes with the rudder pedals, pull the handle aft, and rotate it 90˚ down.' A ratchet spring then holds the park brake in position.
On-site examination of the aircraft brake system established that the park brake was inoperative. The ratchet spring from the park brake handle had fractured, which rendered the park brake system unable to independently remain locked and set. A thorough search of the aircraft cabin did not locate the remainder of the ratchet spring. Examination of the park brake assembly at the ATSB's technical facilities in Canberra was unable to indicate whether the park brake mechanism was operative prior to the accident.
Tie down
A tie down kit was located in the aircraft, but there was no provision for a tie down in the location the aircraft was parked.
Throttle control
The throttle control was of the push-pull type, incorporating a friction lock, which is rotated for the desired friction level. The throttle is open in the fully forward position and closed in the fully aft.
Post-accident inspection of the aircraft controls found the throttle to be at about one third of its possible travel. The friction knob was consistent with no friction on the throttle control.
The measured throttle position was equivalent to a higher setting than the POH engine start checklist position. However, as the friction lock was not set, it could not be determined if this was the same position as when the aircraft propeller was hand swung.
Related occurrences
A review of the ATSB occurrence database identified 39 other reported incidents involving hand starting an aircraft resulting in injuries and substantial damage to property. The database contained all reported occurrences from 1969. The majority of incidents identified inadequate aircraft restraint and excessive throttle settings as factors in the aircraft moving after a hand start. Of these, a number were identified where the aircraft park brake and wheel chocks were used but were not adequate to restrain the aircraft. This included the investigation detailed below.
The pilot attempted to start the engine for the return flight to Darwin, but the starter motor failed to operate. He then applied the handbrake, chocked the nose-wheel and hand-swung the propeller. After several attempts the engine fired then ran at a high RPM speed causing the aircraft to jump over the chock and head towards the airport fence. After unsuccessfully attempting to enter the cabin the pilot tried to grab a main wheel, but missed. He next grabbed at the tailplane but was knocked to the ground. The empty aircraft then ran through the airport fence, across a road and into a ditch, where it came to rest suffering substantial damage.
The sources of information during the investigation included:
Witnesses
Maintenance staff
the Civil Aviation Safety Authority
Adelaide Airport Limited
Cessna (Textron Aviation)
South Australia Police
References
FAA-H-8083-3A, Airplane flying handbook. (2004). U.S. Dept. of Transportation, Federal Aviation Administration, Flight Standards Service.
Information Manual, Cessna Model 172RG. (1983). Cessna Aircraft Company, Wichita, Kansas USA
Submissions
Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.
A draft of this report was provided to Cessna (Textron Aviation), the Civil Aviation Safety Authority and the United States National Transportation Safety Board.
Submissions were received from the Civil Aviation Safety Authority and the United States National Transportation Safety Board. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.
Findings
From the evidence available, the following findings are made with respect to the ground handling accident involving Cessna 172RG, registered VH-MKG, Parafield Airport, South Australia on 11 September 2016.
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
Contributing factors
The aircraft battery had insufficient charge to start the engine, resulting in the pilot starting the engine by hand swinging the propeller.
The aircraft was not adequately secured during the hand start and had no one at the controls, resulting in fatal injuries to the pilot and damage to another aircraft when it taxied away.
Other factors that increased risk
Unrestrained animals in the aircraft cabin can adversely affect safety during aircraft operations.
Safety analysis
Starting procedures
Normal operating procedures for the aircraft relied on the battery having sufficient power to start the engine. Evidence gathered during the investigation indicated that the battery was known by the pilot to be unserviceable prior to the accident. It could not be determined why the battery had not been replaced prior to conducting the ground run. Similarly, it was unable to be determined why the available GPU was not used.
The pilot was known to have hand swung aircraft previously, including MKG. The use of either the park brake or wheels chocks, or a combination of both, may have been sufficient to hold the aircraft on previous occasions. However, the aircraft manufacturer indicated that neither the use of chocks nor the park brake were designed to hold the aircraft during an engine start, and were only intended to hold a parked aircraft.
The pilot was hand starting the aircraft unassisted, using only small chocks and without tying down the aircraft, and would therefore have been relying on the park brake being set. If the spring was broken prior to the park brake being set, or broke at the time the brake was set, the pilot would have been alerted to this as the park brake handle would have returned to its initial position. It remains possible that the spring failed between the time the brake was set and the time the engine was started, leaving the pilot unaware that the park brake was not set. This reinforces the recommendations to have a qualified second person at the controls when attempting to hand start.
Other factors that increased risk
Unrestrained animal
Civil Aviation Regulation 256A - Carriage of animals, allows animals to be transported on aircraft. The regulation requires any animal to be in a container or adequately restrained in order to prevent adversely affecting the safe operation of the aircraft.
While it could not be determined in this instance if the presence of the dog had any impact on the accident, an unrestrained animal in the cockpit or cabin area of an aircraft increased the risk of inadvertent interference with aircraft control settings.
Purpose of safety investigations & publishing information
Purpose of safety investigations
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
Creative Commons licence
With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
On 7 September 2016 at 1720 UTC,[1] Scoot Airline flight TZ026, a Boeing 787 aircraft, registered 9V‑OFG, departed Singapore on a scheduled passenger transport flight to Melbourne, Victoria.
Flight TZ026 made an approach to Melbourne Airport runway 34 and landed without incident at 0021 UTC on 8 September 2016. During the landing roll, the flight crew used maximum reverse thrust in order to vacate runway 34 at Taxiway F (Figure 1). After the aircraft exited the runway onto Taxiway F, air traffic control (ATC) instructed the flight crew to change radio frequency to the ATC Ground frequency. The surface movement controller (SMC) then provided the flight crew with their taxi instructions.
The flight crew proceeded to taxi the aircraft from Taxiway F, right onto Taxiway T, then another right onto Taxiway A. As they started to taxi down Taxiway A, they heard a comment on the Ground frequency about smoke. The flight crew were unsure if the comment was in reference to their aircraft, so they queried the SMC. The SMC responded that flight TZ026 had smoke coming from their right engine. The captain elected to stop the aircraft on the taxiway and request an inspection from the aviation rescue and fire-fighting (ARFF) services.
Figure 1: Aircraft ground track at Melbourne Airport
Source: Google earth, annotated by ATSB
The ARFF vehicles arrived in front of the aircraft on Taxiway A and an ARFF officer communicated their observations of the right engine to the SMC. The SMC directed the flight crew to monitor the frequency in use by the ARFF. Consequently, the flight crew heard the ARFF officer report to the SMC that the smoke they saw ‘appeared to be normal’. The aircraft captain was aware that the aircraft engines can emit smoke from the engine oil system and cross-checked their engine indications. There were no abnormal indications present and therefore the captain elected to taxi the aircraft to their allocated parking bay and conduct a normal shut down with ARFF in attendance. The aircraft was shut down without further incident.
Maintenance fault finding
After the passengers had disembarked, the captain informed one of the company maintenance engineers that smoke had been observed coming from the right engine after landing, but all engine indications were normal. The engineer conducted a general visual inspection of the engine and reported to the captain that there was no obvious sign of a fault. The captain documented the incident in the aircraft technical log and signed-off duty.
During the turn-around inspection, another company maintenance engineer noted that the right hydraulic system was at the refill level. The engineer conducted leak checks on the right hydraulic system and found a damaged hydraulic hose in the right engine pylon hydraulic bay (Figures 2 and 3). The damaged hose was located downstream of the right engine thrust reverser stow line.
Figure 2: Location of aircraft hydraulic systems and leak
Source: Boeing, annotated by ATSB
Figure 3: Location of hydraulic hose
Source: Boeing
Flight data recorder
The engine thrust reversers are electrically controlled, but hydraulically powered systems. The right hydraulic system powers the right engine thrust reverser and the left system powers the left engine thrust reverser. Flight data recorder information indicated that the three hydraulic systems were at the same quantity when the aircraft landed. When the thrust reversers were applied to assist braking, the left and right hydraulic system quantities reduced, as required, to power the thrust reverser actuators. However, when the thrust reversers were stowed only the left hydraulic system returned to the normal quantity. The right system quantity continued to reduce, which was consistent with a leak in the hydraulic system.
Aircraft manufacturer findings and recommendations
The failed hose was part of the thrust reverser retraction circuit and is otherwise isolated during flight. The thrust reverser circuit is the only location where this part is installed on the aircraft. Boeing note that the leak has previously been observed either as drip from the aft fairing of the engine pylon after flight, or during landing as a mist sprayed from the engine exhaust during thrust reverser retraction. Boeing has advised operators to heighten their awareness of the issue, and in the event of an observed leak at the aft pylon fairing module, to check the incident part number hose for a rupture. Boeing has recorded several in-service failures of this part number hose and investigated the fault with the part manufacturer.
Engine manufacturer findings
During development testing of the engine, the manufacturer, Rolls Royce, identified the potential for a visible white-coloured mist from the engine oil breather to occur at any stage of engine operation. They stressed that this is a normal characteristic of the engine, which is a result of incomplete air/oil separation, and ‘does not represent an increase in engine oil consumption.’
Aircraft captain comments
The captain noted that during the inspection from the ARFF services, the flight crew were asked by the SMC to monitor the ARFF frequency, but they were not allocated a discrete frequency for communications with ATC. This resulted in interruptions from other traffic using Ground frequency for routine communications and at times the captain felt they could not immediately relay information to ATC.
Airservices comments
Airservices noted the captain’s comment regarding the need for a discrete frequency. This is currently not standard practice and has the potential to create confusion for ATC at times of high workload. The use of a published frequency can aid in situational awareness for other operators and ARFF services throughout the emergency.
Safety analysis
Hydraulic leak
During the turn-around inspection of the aircraft, the right hydraulic system fluid level was found to be low due to a ruptured hydraulic hose. This hydraulic hose is only installed in the engine thrust reverser retraction circuit and is otherwise isolated inflight. The flight data indicated that the reduction of fluid in the right hydraulic system, consistent with a hydraulic fluid leak, coincided with the thrust reverser retraction after landing.
Engine smoke
At the time that the aircraft stopped for a visual inspection by ARFF, what was reported as smoke appears to be mist emanating from the vicinity of the engine oil breather (Figure 4). The presence of mist is consistent with the Boeing investigation into the failures of the affected hydraulic hose that indicates a rupture of this hose. However, the location of the mist suggests the source could have been (by itself or in addition to the hydraulic fluid) due to the engine oil breather. This is because the mist was also consistent with what Rolls Royce had previously noted as a visible white-coloured mist that can be observed emanating from the engine oil breather as a result of incomplete air/oil separation.
Figure 4: Aircraft stopped for inspection
Source: Melbourne Airport
Findings
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
The hydraulic hose in the right engine thrust reverser retraction circuit ruptured when the right engine thrust reverser was retracted on landing.
The reported engine smoke was probably mist from the right hydraulic system leaking hydraulic fluid into the engine exhaust, or mist from the engine oil breather as a result of incomplete air/oil separation, or a combination of both conditions.
Safety action
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.
Aircraft manufacturer
As a result of this occurrence and previous occurrences, Boeing has advised the ATSB they have taken the following safety action:
A ‘capture and control in production’ process was introduced. This process has identified and screened out defective parts. Their own investigation has identified the likely root causes of the failures and identified the population of hoses affected. They have communicated recommended actions to aircraft operators, which describes how to identify and replace potentially affected hoses.
Aircraft Operator
As a result of this occurrence, Scoot Airlines has advised the ATSB they are taking the following safety action:
As per the aircraft manufacturer’s recommendations, a 787 fleet check was conducted, potentially affected hoses identified, and replacement hoses ordered.
Safety message
At each stage during this incident: after the aircraft had landed, when the engineering inspection detected a low hydraulic system fluid level, and subsequently when the manufacturer received the failed part, the exact nature of the problem was unclear. However, at each stage, precautionary action was taken to investigate the problem, which mitigated the risk to the safety of personnel and serviceability of the aircraft.
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
Creative Commons licence
With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
On 7 September 2016, an Emirates Boeing 777-31HER aircraft, registered A6-EGA, was operating a scheduled passenger flight from Dubai, United Arab Emirates, to Brisbane, Queensland. On board were 22 crewmembers and 308 passengers.
At about 1916 Central Standard Time (CST), the left engine oil quantity started to decrease from 16.4 quarts, stabilising at 2 quarts at 1927, when the aircraft was about 650 km north-west of Adelaide, South Australia, and at flight level (FL) 353.[1] The flight crew contacted company engineering and operations staff and advised them of the situation.
The flight crew received a left engine low oil engine-indicating and crew-alerting system (EICAS) message and conducted the associated non-normal checklist. At about 1951, the flight crew shut the left engine down (Figure 1).
Figure 1: Flight data plot including oil pressure and engine shutdown
Source: Aircraft operator analysed by ATSB
The flight crew contacted air traffic control, declared a PAN[2] and conducted a diversion to Adelaide Airport, which was the nearest suitable airport. The flight crew commenced a gradual descent to FL 270, and were subsequently cleared for the area navigation (RNAV) approach to runway 05 at Adelaide. The aircraft landed without incident, and arrived at the parking bay at 2056. There was no damage to the aircraft or injuries to crew or passengers.
A subsequent engineering inspection found the left oil supply line to bearings numbers 4 and 5 had fractured and the associated clamp was broken (Figure 2).
Captain comments
The captain commented that the flight crew managed the situation in accordance with their procedures. The weather in Adelaide was beautiful and the aircraft performed well and handled exactly as it did in the simulator in training.
Engine manufacturer investigation
The manufacturer is investigating the following aspects:
Turbine centre frame (TCF) Supply Tube 2061M79G02:
evaluating high cycle fatigue (HCF) capability of the TCF tube when a clamp is separated/broken
studying tube dynamic behaviour, due to broken clamps and its interaction with external components.
Numbers 4 and 5 Oil Supply Tube 2034M68G01:
evaluating effects of missing piston ring and clamp separation on the external hardware
correlating finite element analysis (FEA) (stress analysis) with event findings
running analysis to verify integrity of current system.
Clamp Damage:
mapping broken clamp findings from operator data and shop inspections
reviewing installation procedures and design characteristics and their effect.
Figure 2: Fractured oil supply line
Source: Aircraft operator
Safety analysis
The left oil supply line to bearings numbers 4 and 5 fractured, resulting in a loss of oil and oil pressure from the left engine. The flight crew received a left low oil pressure warning and followed the associated checklists, shut down the left engine and diverted the aircraft to Adelaide.
Findings
These findings should not be read as apportioning blame or liability to any particular organisation or individual.
The oil supply line to bearings 4 and 5 fractured at a welded joint and its support clamp was broken, resulting in an oil leak and therefore low oil pressure and quantity in the left engine.
Following the receipt of a left low oil pressure warning, the flight crew completed the non-normal checklist, shut down the left engine and conducted a diversion to Adelaide.
Safety action
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following safety action in response to this occurrence.
Aircraft operator
The operator performed a fleet-wide inspection and found no leaks or cracks on any other engine.
Safety message
This incident provides an excellent example of effective crew resource management techniques when faced with an abnormal situation. Additionally, regular proficiency checks in the simulator including scenarios of a single engine failure allow flight crew to respond appropriately in the event of such an occurrence in flight.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
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With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
On the morning of 27 August 2016, a Van’s RV-7 aircraft, registered VH-VTZ, and a Glaser-Dirks DG-400 motor-glider, registered VH-XJZ, were both prepared for flight from Gympie aircraft landing area (ALA), Queensland.
The pilot taxied the motor-glider from the Gympie ALA glider hangars and back-tracked on the grass alongside runway 14 (Figure 1). Before entering the runway strip, the pilot made a radio broadcast on the common traffic advisory frequency (CTAF) 126.7, that they were entering and back-tracking runway 14. On arrival at the runway threshold, the pilot made another broadcast that they were lining-up on runway 14. The pilot taxied the motor-glider onto the threshold of runway 14 and conducted their engine run-up checks. After about 10–15 seconds, they made a broadcast that they were rolling on runway 14 and released the brakes for take-off.
At about the same time as the motor-glider was backtracking runway 14, the pilot of the RV-7 made a broadcast on the CTAF that they were taxiing from the general aviation hangars. At the runway holding-point, the pilot then made a broadcast that they were entering and back-tracking runway 14 (Figure 1). Neither pilot heard the broadcasts from the other pilot.
The motor-glider started the take-off roll from the threshold of runway 14 and as it approached take-off speed, the pilot noticed the top of another aircraft (RV-7) appear on the horizon. Both pilots applied their aircraft brakes and veered to their right. The aircraft came to a stop next to each other on the runway abeam the glider hangars at about 1110 Eastern Standard Time (EST). The pilots performed a radio check and verified they could hear each other and both were broadcasting on the CTAF 126.7. They then proceeded on their planned flights without further incident.
Gympie runway slope
From the runway 14 threshold, runway 14 slopes upward to a crest, which is in line with the glider hangars (Figure 1). Runway 14 then slopes downhill to the threshold of runway 32. The motor-glider pilot commented that in an aircraft low to the ground, such as a glider, stationed at the threshold of runway 14, the pilot would not be able to see an aircraft such as the RV-7, back-tracking runway 14, until the other aircraft was abeam the glider hangars (Figure 1). The RV-7 pilot commented that when back-tracking runway 14 in their aircraft they cannot see another low profile aircraft, such as a glider, until they are about 300 m from the threshold of runway 14.
Aircraft radios
The RV-7 has one radio antenna located on the underside of the aircraft. The motor-glider pilot was unsure of the location of their radio antenna, because they are integral to the airframe in order to minimise drag. Both aircraft radio systems are capable of monitoring two frequencies, but can only broadcast on one. Both pilots confirmed they had 126.7 CTAF set and in use as their active frequency at the time of the serious incident. However, the RV-7 pilot commented that their radio microphone may not have been up against their mouth, which would have reduced the volume of their transmissions.
Figure 1: Gympie ALA and ground tracks of the aircraft
Source: Google earth, annotated by ATSB
Previous incidents
Both pilots commented that there have been previous incidents of traffic conflicts between aircraft, which started with missed radio calls when the aircraft were at opposite ends of the main runway (runway 14/32). On these previous occasions, aircraft airborne in the circuit could hear the radio calls of opposite end traffic on CTAF, despite the traffic on the ground not hearing each other.
A search of the ATSB notifications database indicated that in 2016 there were two incidents at Gympie ALA, where the reporter has indicated that a broadcast was either not made, or not heard. It is unknown if terrain shielding contributed to these events.
ATSB comment
The ATSB notes that it is reported that traffic at Gympie ALA is increasing and therefore exposure to the risk presented in this report is increasing. Despite the fact that both pilots made all the required radio calls for their planned operation, a runway conflict occurred. There is currently no reference to the potential for terrain shielding of radio calls in the Gympie ALA Enroute Supplement Australia entry.
Safety action
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.
RV-7 pilot
As a result of this occurrence, the pilot of the RV-7 has advised the ATSB that they are taking the following safety action:
Radio checks
The pilot of the RV-7 indicated they would introduce a radio check broadcast, when circumstances permit, during their start checks to verify their transmission volume and readability.
Aerodrome Operator
As a result of this occurrence, the Gympie Aerodrome Operator has advised the ATSB that they are taking the following safety action:
Enroute Supplement Australia
The Gympie Aerodrome Operator indicated they intend to add a note to the Gympie entry in the Enroute Supplement Australia, under ‘Additional Information’, to advise pilots that poor radio propagation between aircraft operating on the ground at opposite ends of the main runway may be experienced.
Safety message
A potential accident was avoided by the actions of both pilots who responded to the presence of the other aircraft by braking and veering to the right. Rather than continuing their flights with the assumption the other made a mistake, they performed a radio check with each other to verify there was no fault with their respective aircraft radios.
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
Ownership of intellectual property rights in this publication
Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.
Creative Commons licence
With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.
Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.
The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.
