The helicopter was operating a Night VFR medical evacuation flight. The patient to be evacuated was a 15 year old adolescent who had suffered a dislocated elbow.
Initial advice of the requirement for the evacuation was telephoned by the tasking hospital at about 2030 EST and after obtaining weather forecasts and readouts of the present weather in the area of the destination, the aircraft departed for the short flight to the hospital at 2108.
At the hospital, the pilot checked with the medical staff as to the need to conduct the evacuation and was advised that the flight was necessary. After emplaning a doctor the aircraft departed for its destination.
As the flight proceeded the pilot checked the weather conditions at the island with persons at the destination and at a location to the south of the destination. Checks were also made through the Flight Service operator with the meteorological radar service in Brisbane. The weather report received from the destination indicated a complete overcast with a south-easterly wind of 15-20 kts and no rain.
The flight continued along the eastern side of Fraser Island and the pilot reported that he had the lights at the destination in sight. Enroute, over the island, the helicopter was forced to descend to about 1000 feet to remain below the overcast. As the helicopter approached the destination it entered rain and the pilot commenced a descent. The rain became heavier and the pilot lost sight of all but one of the three light sources at the destination. He continued with the descent and decided that because of the conditions he would be unable to conduct a turn to clear the area.
The helicopter subsequently struck a tree and began to vibrate. After it struck another tree the pilot closed the throttle and flared the helicopter, which came to rest upright about 400 m prior to the threshold of the Orchid Beach airstrip.
Weather reports received by the pilot prior to and during the flight indicated that visual flight was possible to the destination. However, the reports also indicated that the heavy showers to the north of the destination were moving to the south.
SIGNIFICANT FACTORS
There was pressure on the pilot to complete the evacuation.
The weather conditions in the area of the destination deteriorated rapidly.
The pilot continued with the flight into non-visual conditions.
At about 0600 Central Daylight-saving Time (CDT) on 7 November 2014, a Boeing 737-800, registered VH-VUR and operated by Virgin Australia, departed Adelaide, South Australia, on a scheduled service to Brisbane, Queensland. The captain was the pilot flying and the first officer was the pilot monitoring.
The crew were cleared via the SEDAN 9 Standard Instrument Departure (SID). As the aircraft climbed through about 4,400 ft during the SID, air traffic control re-cleared the aircraft to track direct to waypoint UVUPU (north-east of Mildura, Victoria), and cancelled the standard airspeed restriction of 250 kt below 10,000 ft. The crew made appropriate changes in the Flight Management Computer (FMC),[1] following which the captain selected Lateral Navigation (LNAV)[2] and Vertical Navigation (VNAV) auto-flight modes (see VNAV mode). In these modes, the aircraft commenced tracking directly to waypoint UVUPU, and accelerated to the FMC-programmed airspeed of 280 kt.
The climb proceeded normally until the aircraft was passing about flight level (FL) 250[3] when the captain selected Level Change (LVL CHG) vertical auto-flight mode (see LVL CHG mode), and commanded a continued climb at the existing airspeed of 280 kt. The captain recalled that LVL CHG mode may have been selected to manage continued climb through a layer of turbulence. The crew intended to re-select VNAV mode when LVL CHG mode was no longer required, but inadvertently overlooked that selection, and the climb continued in LVL CHG mode at 280 kt.
Soon after the selection of LVL CHG mode, as the aircraft climbed through about FL 265, the auto-flight system sequenced automatically from climb at a constant airspeed, to climb at a constant Mach number,[4] consistent with normal system behaviour. Climb then continued above FL 265 at a constant Mach number of 0.69, which was the Mach number corresponding to 280 kt at the time the changeover occurred. As the aircraft continued to climb at the constant Mach number, the airspeed slowly reduced (as a function of the characteristics of the atmosphere and the relationship between Mach number and airspeed).
The slowly reducing airspeed went unnoticed by the crew until the auto-flight system was levelling the aircraft at the planned cruise altitude of FL 390. At about that time, the captain noticed that the magenta airspeed bug[5] on the primary flight display (PFD) airspeed indicator was at the top of the minimum manoeuvre airspeed amber bar. At that point, the top of the amber bar corresponded to an airspeed of about 216 kt. The crew also noticed a ‘buffet alert’ advisory message appear in the scratchpad of Control Display Unit (CDU).[6]
In response to the low airspeed condition, the captain selected Mach 0.77 on the Mode Control Panel (MCP)[7] to initiate acceleration towards the FMC-programmed cruise Mach number. As the aircraft accelerated through about Mach 0.74, the captain selected VNAV and the auto-flight system engaged in VNAV Path (VNAV PTH) (see VNAV mode), allowing the aircraft to continue accelerating to the FMC-programmed cruise Mach number of Mach 0.77 while maintaining FL 390. Under the existing conditions, a Mach number of 0.77 corresponded to an airspeed of about 240 kt. Having accelerated to Mach 0.77, the flight continued to Brisbane without further incident.
Figure 1 provides a graphical illustration of some relevant flight parameters and auto-flight system vertical modes from FL 200 until the aircraft had accelerated to Mach 0.77 in cruise flight at FL 390. Of particular note is the change from VNAV mode to LVL CHG mode soon after 1952 UTC.[8] The figure also shows the near constant Mach number and gradually decreasing airspeed from about 1953 UTC, until the aircraft reached the planned cruise altitude soon after 2001 UTC. The airspeed dips beneath the minimum manoeuvre airspeed for a short time as the crew initiated acceleration, reaching a minimum recorded airspeed of about 211 kt. From that point, the aircraft accelerates to the planned cruise Mach number of Mach 0.77, with VNAV re-engaged just before 2004 UTC. Note that the minimum operating airspeed referred to in Figure 1 is the same as the minimum manoeuvre airspeed (see below). The computed airspeed referred to in Figure 1 is the same airspeed that would have been displayed on the captain’s PFD.
Figure 1: Selected flight parameters and auto-flight system modes
Source: ATSB
Relevant technical information
The auto-flight system consists of an auto-pilot flight director system (AFDS) and an auto-throttle system. The AFDS and auto-throttles are controlled using the FMC and the MCP. The auto-flight system operates in various vertical modes according to the phase of flight, operating environment and crew requirements. Two commonly used vertical modes relevant to this occurrence are VNAV mode and LVL CHG mode.
VNAV mode
During a climb in VNAV mode, the auto-flight system guides the aircraft along the FMC-programmed vertical profile, at the speed (airspeed or Mach number) computed by the FMC, modified and selected by the crew as required according to operational circumstances. During normal operations, the FMC speed profile holds the airspeed at 250 kt up to 10,000 ft (normal procedural requirement in Australian airspace) followed by acceleration to the FMC-programmed climb airspeed (commonly the economy-optimised speed schedule computed by the FMC). As climb continues at a constant airspeed, Mach number increases as a function of the characteristics of the atmosphere and the relationship between Mach number and airspeed. Climb continues at the FMC-programmed airspeed until the Mach number reaches the FMC-programmed Mach number, from which point climb continues at that Mach number. The crew can change FMC-programmed climb speeds as required, by making the required changes on the appropriate page of the CDU. During this occurrence, the recorded data indicates that, had the crew continued to climb in VNAV mode (rather than selecting LVL CHG), the aircraft would have maintained 280 kt to about FL 320, from which point climb would have continued at a constant Mach 0.77.
VNAV mode is selected by pressing the VNAV pushbutton on the MCP. When selected, a green bar on the VNAV pushbutton illuminates. During a climb in VNAV mode, the flight mode annunciator (FMA)[9] indication at the top of each pilot’s PFD indicates N1[10] as the auto-throttle mode and VNAV SPD (speed) as the vertical auto-flight mode (Figure 2). During a climb in VNAV mode, the FMC-programmed speed is displayed on the PFD, and the indicated airspeed/Mach number (IAS/MACH) window on the MCP is blank.
When the aircraft levels at the FMC-programmed cruise altitude, the auto-flight system vertical mode sequences to VNAV PTH (path) to maintain the cruise altitude, and the auto-throttle mode sequences to FMC SPD (speed) to hold the FMC-programmed cruise speed (Mach number). Similar annunciations appear when the auto-flight system levels the aircraft temporarily at an intervening FMC-programmed altitude constraint (there were no intervening altitude constraints relevant to this occurrence).
LVL CHG mode
During a climb in LVL CHG mode, the auto-flight system controls the aircraft pitch attitude in a manner that maintains the speed selected by the crew on the MCP. LVL CHG mode is sometimes used during a climb to allow a more active and typically short-term approach to vertical profile management. For example, rather than allowing the aircraft to accelerate in VNAV mode in accordance with the FMC-programmed speed profile, the crew may elect to temporarily retard acceleration or reduce speed using LVL CHG mode. Temporarily retarding acceleration or reducing speed may generate a higher short-term rate of climb, thereby facilitating an expedited climb through a layer of cloud or turbulence.
LVL CHG mode is selected by pressing the LVL CHG pushbutton on the MCP. Like the VNAV pushbutton, a green bar illuminates on the pushbutton when LVL CHG is selected. The speed control knob on the MCP is then used to select the required climb airspeed or Mach number, which is displayed in the corresponding IAS/MACH window. When LVG CHG mode is selected, the FMA indicates N1 as the auto-throttle mode and MCP SPD (speed) as the vertical auto-flight mode (Figure 2).
Figure 2: Relevant example FMA annunciations (VNAV upper example and LVL CHG lower example)
Source: ATSB
Minimum manoeuvre airspeed
The minimum manoeuvre airspeed is represented as the top of an amber bar on the PFD airspeed indicator. Minimum manoeuvre airspeed is defined in the operator’s Flight Crew Operations Manual (FCOM) as the airspeed that provides:
1.3g[11] manoeuvre capability to the stick shaker below approximately 20,000 ft.
1.3g manoeuvre capability to the low airspeed buffet (or an alternate approved manoeuvre capability entered into the FMC maintenance pages) above approximately 20,000 ft.
The FCOM adds the following caution:
Reduced maneuver capability exists when operating within the amber regions below the minimum maneuver speed or above the maximum maneuver speed. During non-normal conditions the target speed may be below the minimum maneuver speed.
During this occurrence, the crew noticed that the airspeed was near the minimum manoeuvre airspeed on the PFD, and noticed the ‘buffet alert’ message on the CDU scratchpad, and responded accordingly. Other more salient system alerts and levels of protection were available had the crew not responded when they did, and the airspeed had continued to reduce. These include an aural ‘airspeed low’ alert and, following further airspeed reduction, a stick-shaker system.[12] Under some conditions the auto-flight system may also command a reduction in the aircraft pitch attitude (accepting a reduction in the rate of climb in return for airspeed management), if the airspeed reaches the minimum manoeuvre airspeed.
Crew comments
During the operator’s investigation into the incident, the crew commented that a number of distractions may have contributed to the incident. The crew commented that sun glare was particularly problematic – the glare was directly through the windscreen for the duration of the climb. The crew also commented that they may also have been distracted by air traffic control and cabin-related communication requirements, and other air traffic in their vicinity. Additionally, both pilots consumed breakfast during the climb (at separate times), which may have provided a source of distraction.
ATSB comment
In a similar occurrence involving the same aircraft type, the crew inadvertently allowed the aircraft to continue to climb in LVL CHG mode at a constant Mach 0.62. On that occasion, the crew noticed the ‘buffet alert’ message and a small pitch attitude reduction as the aircraft climbed through about FL 350 and the airspeed neared the minimum manoeuvre airspeed. A copy of the report associated with that incident is available on the ATSB website.
A recent report by the FAA Performance-based Operations Aviation Rulemaking Committee, (Commercial Aviation Safety Team Flight Deck Automation Working Group) titled Operational Use of Flight Path Management Systems made a number of findings and recommendations dealing broadly with vulnerabilities associated with flight crew management of automated systems. Further to a 1996 FAA report titled The Interfaces Between Flightcrews and Modern Flight Deck Systems, the more recent report commented that ‘…autoflight mode selection, awareness and understanding continue to be common vulnerabilities’. Both the 1996 report and the later Automation Working Group report are available on the FAA website.
ATSB Research Investigation B2004/0324 titled Dangerous Distractions found that pilot distraction contributed to 325 occurrences involving Australian-registered aircraft between 1997 and 2004. The report concluded:
… the findings have shown that distractions have the potential to significantly threaten flight safety across all sections of the industry and during all phases of flight. Clearly, strategies to minimise pilot distraction need to be developed and designed with particular attention to the operations being undertaken.
The report, which includes some strategies for reducing pilot distraction, is available on the ATSB website.
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 intended to highlight relevant human factors issues, such as the potential distractions associated with sun glare and communications, in future training programs.
Safety message
For flight crew, this incident highlights the importance of continued auto-flight system mode and aircraft energy state awareness. The incident also highlights the manner in which various distractions have the potential to adversely affect such awareness. For operators, the incident highlights the importance of robust auto-flight management procedures, supported by appropriately focussed crew training and standardisation.
In 2010, the European Aviation safety Agency issued a Safety Information Bulletin on the subject of Flight Deck Automation Policy – Mode Awareness and Energy State Management. The bulletin included a number of recommendations to operators addressing automation policies, procedures and training. A copy of the bulletin is available at European Aviation Safety Agency. Operators of highly automated aircraft are encouraged regularly review their own automation policies, procedures and training in the context of the recommendations included in the bulletin, and with the benefit of lessons learned from this and similar incidents.
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 14 November 2014, at about 1230 Eastern Daylight-saving Time (EDT), a de Havilland Canada DHC-1 (Chipmunk) aircraft, registered VHRVY (RVY), departed from Luskintyre Airfield, New South Wales, for a post-maintenance flight with the pilot and one passenger on board. The flight plan was to conduct the flight near the airfield and at a safe altitude. The aircraft had a history of ongoing problems with both the engine revolutions per minute (RPM) governing system as well as the rear vertical speed indicator (VSI). The passenger who was seated in the rear seat was to monitor and report any engine RPM fluctuations and observe the VSI indication.
After about 10 minutes of straight and level flight, as well as climbs and descents, with no fluctuations in the engine RPM, the pilot commenced some gentle aerobatics. These aerobatics were to ensure the selected engine speed was maintained through a range of flight attitudes and airspeeds. As everything appeared to be functioning correctly, the pilot then progressed to some more advanced aerobatic manoeuvres.
As the aircraft was exiting the bottom of a modified loop manoeuvre, at around 140 kt indicated airspeed (IAS), the engine began to over speed without warning.[1] The pilot reduced the engine power and commenced trouble shooting the problem.
At the time, RVY was about 1 km north of Luskintyre Airfield (Figure 1), heading east at about 3,000 ft above ground level (AGL). The westerly wind was reported to be gusting at around 2030 kt. The pilot joined downwind for a landing on runway 30, noting the groundspeed was around 150-160 kt. While on downwind, the pilot advanced the throttle lever and noted that at about 1/3 lever movement the engine speed was at about 3,000 RPM (maximum continuous RPM at sea level pressure altitude is 2,700). Despite the engine speed, the aircraft was not able to maintain altitude. In an attempt to ‘get back’ to the airfield the pilot turned from a slightly extended downwind onto a ‘base leg’. As the aircraft turned, the engine stopped producing power. The pilot unsuccessfully attempted to restart the engine.
When RVY turned onto a final approach, the aircraft was still descending. At about 500 ft AGL, the pilot determined that they would not make the runway, so he elected to land in a paddock about 500 m east of the airfield (Figure 1). During this manoeuvre, the right wing stalled and dropped slightly. To recover, the pilot lowered the nose of the aircraft to gain more airspeed. The pilot reported that due to the high outside air temperature and gusting wind, the conditions were quite turbulent near the ground. The pilot flared the aircraft in preparation for landing and noted airframe buffeting, with little to no response from the elevator. The aircraft landed heavily, travelling through an electric fence before the aircraft stopped on a drive way just short of the selected landing area (Figure 1).
The pilot exited the aircraft quickly as the right wing fuel tank had ruptured during the landing and fuel had spilt onto the ground. The pilot tried to assist the passenger, but due to the pilot’s injuries he was unable to provide any physical assistance. After a short time, the passenger exited the aircraft. The pilot and passenger sustained serious injuries and the aircraft was substantially damaged (Figure 2).
Figure 1: Accident location
Source: Google™ earth, annotated by the ATSB
Figure 2: VH-RVY
Source: New South Wales Police Force
Aircraft information
The aircraft was manufactured in the United Kingdom in 1951 and was first registered in Australia in 1954. The aircraft had been modified by the previous owner, between 1978 to 1983, where the de Havilland Engine Company Gipsy Major engine and fixed pitch propeller instillation was replaced with a Lycoming IO-360A1B6 engine, constant speed propeller, propeller governor and an accumulator installation.
Pilot comment
The pilot worked for the maintenance organisation and had flown the aircraft after its last maintenance in 2013. The pilot indicated that at the annual maintenance inspection in 2013, small fluctuations in the selected engine RPM had been reported. Both the propeller and propeller governor were sent to be overhauled and reinstalled on the aircraft, however there continued to be slight RPM fluctuations. After the annual inspection conducted just prior to the accident, it was found that there was about a 100 engine RPM fluctuation, during gentle climbing and descending. The propeller governor and accumulator were again sent to be overhauled. The components were returned serviceable with no defects found. The pilot reported that during the overhaul some adjustments were made to the internal operating pressures of the propeller governor. The components were reinstalled on RVY and ground tested with no defects found.
The pilot believed that coming out of the modified loop manoeuvre the propeller had gone into full fine pitch, resulting in the engine entering an “overspeed” condition.
The pilot reported that apart from the strong gusty winds, the temperature was about 39°C.
Owner investigation
An investigation was conducted on behalf of the owner that found the following:
After the accident, the engine, propeller, propeller governor and accumulator were removed from the aircraft and were inspected and tested to identify any defects.
The engine was functionally tested on an engine test truck and no defects were found.
The propeller was inspected at a propeller overhaul facility and did not find any evidence of damage or failure within the propeller that would explain an uncommanded movement to fine pitch.
The propeller governor was functionally tested at an aircraft component overhaul facility and no defects were identified.
The accumulator was functionally tested at an aircraft component overhaul facility and no defects were identified. The engineering order that approved the installation of the accumulator was reported to specify an accumulator air charge pressure of about 250 PSI. The overhaul facility test equipment was only capable of testing the accumulator to about 100 PSI.
The investigation determined that there was no conclusive reason why the engine suffered an overspeed and ceased to operate. It was suggested that the overspeed may have been a result of lack of oil pressure to the propeller when the engine of RVY was inverted, during the aerobatic manoeuvre resulting in the propeller moving to fine pitch.
Safety message
Engine failure in flight
This accident is a timely reminder to pilots to consider the effect an in-flight engine failure at different altitudes and in the given conditions can have on the options available to manage that failure and to identify a suitable forced landing area. The combination of two people on board and the high temperature would have adversely affected the aircraft’s performance on the day.
pre-flight decision making and planning for emergencies and abnormal situations for the particular aerodrome including a thorough pre-flight self-brief covering the different emergency scenarios.
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.
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.
The operator had received approval to carry out certain low level operations, including power line inspections, during nominated periods of emergency. The approval was subject to a number of conditions, which included requirements that such flights be authorised by the State Emergency Services and that only persons essential to the operation be carried. As suitably qualified commercial pilots were not normally available, two private pilot members of the aero club who had more than 1000 hours flying experience had been specifically approved to conduct these flights. Before receiving this approval, the pilots had been required to complete specialised low flying training and testing. The procedure used in conducting power line inspection flights was to fly at approximately 200 feet above ground level, maintaining about 90 knots airspeed with one or two stages of flap lowered and with the aircraft tracking left of the line to assist inspection by the observer in the right seat.
The aircraft struck the spur line with its propeller and nose gear. The line did not break and the aircraft was pitched vertically to the ground.
Examination of the wreckage found no evidence of mechanical defect or malfunction which might have contributed to the accident.
On 11 November 2014, at about 1130 Eastern Standard Time (EST), a Cessna 210 aircraft, registered VH-JGA (JGA), departed from Cairns Airport, Queensland, for a scenic flight over Green Island and Arlington Reef with the pilot and four passengers on board.
After about half an hour of local flying, the pilot returned JGA to Cairns Airport. During the approach, at about 1,000 ft above ground level, the pilot selected the landing gear down, however, the green landing gear down indicator light did not illuminate. The pilot observed via an inspection mirror that the left main landing gear was just out of the landing gear recess and not in the down and locked position. The nose landing gear and right main landing gear appeared to be in the down position. The pilot advised the Cairns Tower air traffic controller that JGA would conduct a missed approach and requested a clearance to hold over the sea to determine the reason for the malfunction.
While holding over the sea, in the vicinity of Cairns Airport, at about 1,000 ft, the pilot conducted a landing gear emergency extension, but the left main landing gear still did not lock in the down position. The pilot contacted the operator and maintenance organisation via a mobile phone and conducted extensive troubleshooting, but was unable to get the left main landing gear to lock in the down position.
JGA was then returned to Cairns Airport and the pilot conducted a low level pass over the runway so that the landing gear could be observed. The nose landing gear and right main landing gear were observed to be in the down position, while the left main landing gear was observed to be out of the landing gear recess and only extended to about a 45 degree angle. The pilot elected to hold over the sea and reduce the amount of fuel on board, before conducting a landing. The pilot consulted with the operator and the maintenance organisation and decided to land on the grass area, abeam runway 33, with the landing gear retracted.
The pilot of JGA conducted two practice approaches to assess the aircraft configuration and landing area before beginning the approach for a wheels-up landing. The pilot extended the flaps to help slow the aircraft and, after turning onto a long final, briefed the passengers for the landing and instructed them to take up the brace position. Just prior to touchdown, the pilot turned off the master switch and moved the engine mixture control to the cut-off position. At about 1416, the aircraft landed on the fuselage underside on the grass area abeam runway 33 and came to a stop. The pilot and four passengers were uninjured and the aircraft was substantially damaged (Figure 1).
Figure 1: Damage to JGA
Source: Aircraft operator
Pilot comment
The pilot had flown the aircraft on a previous flight that day and had not noticed anything unusual. The pilot commented that there was sufficient fuel on board the aircraft so that there was time to investigate the malfunction and to plan and prepare for the landing.
When conducting the emergency extension, the nose and right main gear went straight to the down and locked position before the emergency extension hand pump was used. The hand pump had no effect on moving the left main landing gear.
Operator comment
The operator conducted an investigation into the accident and determined that the housing of the left main landing gear had fractured (Figure 2), resulting in the gear not extending to the down and locked position. The operator reported that they conducted a visual inspection of the left and right main landing gear actuators for cracks and checked the tightness of the actuator mounting bolts at the periodic (100 hourly or 12-month) maintenance inspections with the actuator in-situ. The last inspection was conducted about 50 hours prior to the accident, with no defects found.
JGA was manufactured in 1981 and, at the time of the accident, the aircraft had about 12,882 hours total time in service. The aircraft was maintained under the Civil Aviation Safety Authority (CASA) maintenance schedule (Civil Aviation Regulations 1988 (CAR) Schedule 5). The left main landing gear was a non-lifed component and had been on the aircraft since new. There was no record that the actuator had been overhauled.
Figure 2: JGA left main landing gear actuator showing the fractured housing
Source: Aircraft operator
Cessna service manual
The Cessna 210 aircraft service manual contained a Supplemental Inspection Document (SID) 32-10-01 (temporary Revision Number 10 dated 1 August 2011) with a compliance date by 31 December 2013 that directly related to the removal and detailed inspection of the main landing gear retraction system. The inspection was to be carried out initially every 3,000 hours total time in service or 10 years whichever occurred first and repeated every 500 hours or 5 years whichever occurred first (JGA was manufactured in 1981 and had about 12,882 hours total time in service). The SID also required verification that Cessna Service Bulletin SEB01-2 Main Landing Gear Actuator Inspection has been accomplished. The Cessna 200 series SIDs were introduced in August 2011 and the CASA current compliance dates have been extended until 30 June 2015 for aerial work and charter operations and 31 December 2015 for private operations to allow for sufficient time for full compliance.
Cessna Service Bulletin SEB01-2 Main Landing Gear Actuator Inspection revision 2 dated 4 June 2007, required the inspection of the main landing gear actuators for the presence of cracks. Indicating that non-compliance with the service bulletin could result in failure of the main landing gear actuator. The service bulletin required the removal and disassembly of the main landing gear actuators and a fluorescent penetrant inspection of the actuator body to be carried out using black light and a magnifying glass to detect any cracks (Figure 3). The inspection was to be carried out initially every 3,000 hours total time in service within the next 100 hours operation and subsequent inspections every 500 hours total time in service thereafter.
Figure 3: Cessna Service Bulletin SEB01-2 Fracture located in JGA main main landing gear actuator inspection area landing gear actuator
Source: Cessna Aircraft operator
Aircraft maintenance
The aircraft operator reported that all Service Letters and Service Bulletins are reviewed by the maintenance organisation and implemented based on experience and at their request.
Information provided to the operator by the aircraft maintenance organisation was that the actuator fractured in what appeared to be one clean break and not a crack that slowly progressed, and that type of crack could occur in a sudden overload situation during the take-off when the landing gear is selected up and the wheels contact the ground. The maintenance organisation also recommended that the Service Bulletin requirements be carried out on aircraft that have exceeded 5,000 airframe hours.
The ATSB investigation AO-2011-115 Flight control system event involving Cessna 210N, VHJHF, 48 km West of Bourke Airport, NSW, 12 September 2011 found that reported elevator control input difficulties resulted directly from the fracture of the aircraft’s two horizontal stabiliser rear attachment brackets. The nature of the failures was typical of the damage sustained by aircraft as they age and move beyond the manufacturer's originally intended design life.
The investigation found at the time, that some aircraft registration holders believed that their aircraft was exempt from the manufacturer’s supplemental inspections, such as the Cessna SIDs when their aircraft was maintained using the CASA maintenance schedule (Civil Aviation Regulations 1988 (CAR) Schedule 5). While the CASA maintenance schedule did not make any specific reference to the incorporation of the manufacturer’s supplemental inspections, it was a CAR requirement that all aircraft be maintained in accordance with approved maintenance data that, by definition, included those inspections.
The ATSB investigation report AO-2011-115 is available at the ATSB website.
CASA issued Airworthiness Bulletin (AWB) 02-048 Compliance with Cessna Supplemental Inspection Documents (SIDs) on 7 April 2014 to clarify the requirement to comply with Cessna SIDs. The AWB comprised Aviation Ruling 01/2014, which stated that compliance with the Cessna SIDs was mandatory, irrespective of the category of operation or the elected maintenance schedule for the aircraft, be it:
CAR 42A Manufacturer’s Maintenance Schedule,
CAR 42B CASA Maintenance Schedule (Schedule 5), or
CAR 42C Approved System of Maintenance.
The AWB also stated that:
Significantly, the SIDs were developed on the assumption that the aircraft had been maintained using the Manufacturer’s Maintenance Schedule, or equivalent (including the incorporation of all applicable Service Bulletins), and do not necessarily take into account modifications or repairs made to the aircraft since manufacture. Therefore, all relevant Service Bulletins need to be incorporated to be in compliance with the SIDs inspections.
Since the accident involving JGA, CASA released Issue 2 to AWB 02-048, dated 10 April 2015, to clarify that those service bulletins listed in the SIDs are required to be incorporated and confirmed that, where specified in the SIDs, on-going inspections are also required to be complied with.
The AWB further stated that:
Therefore, all Service Bulletins that directly relate to the structural integrity of the aircraft need to be incorporated to be in compliance with the SIDs inspections. Please note that some Service Letters and other information referred to in the SIDs requirements were originally discretionary in nature. These documents are now considered mandatory if referred to as part of the SIDs inspections requirements in relation to [principal structural elements (PSEs)] PSEs.
US Federal Aviation Administration (FAA) Service Difficulty Reporting (SDR) database
A search of the US Federal Aviation Administration (FAA) Service Difficulty Reporting (SDR) database found about 65 entries dated from 1995 to 2014 of reported crack or cracks in the main landing gear actuator/s, in the same crack location as specified in the service bulletin or in that area and with the same part number as JGA’s actuator or one of the actuator part numbers listed in the service bulletin. Five entries had originated from Australia. About 20 reports resulted in an inflight incident and eight mentioned landing with the landing gear in the up position or without both main landing gear in the down position.
Although most reports indicated that the crack or cracks were located in the same area specified in the service bulletin, about 15 indicted they originated from one or more of the actuator attachment bolt holes. About 13 cracks had been located while carrying out the requirements of the service bulletin and the same number again were located while conducting a fleet inspection of the actuator. Several mentioned that this is an ongoing issue and suggested that the actuator be redesigned. One report mentioned a loose actuator attachment bolt, while two mentioned that the bolts were correctly torqued.
Although some entries lacked details, about seven specifically mentioned they were found during a scheduled inspection. One mentioned that the actuator had failed 25 hours after a 100 hourly inspection, which specifically checked the actuators externally for cracks. About three entries reported that the actuator had failed subsequently from conducting the requirements of the service bulletin. One reporter indicated that an inspection should be conducted on the actuator any time that the landing gear contacts the ground in other than the fully extended or fully retracted position.
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.
Operator
As a result of this occurrence, the aircraft operator has advised the ATSB that they are taking the following safety actions:
Maintenance action
The operator’s Cessna 210 aircraft fleet will undergo further examination to see if there is any evidence of other potential failures within the fleet.
Safety message
This accident highlights the importance of comprehensive, periodic maintenance inspections and the role of supplemental inspections in maintaining ageing aircraft. As aircraft age, the original maintenance schedules may not be sufficient to ensure the aircraft’s ongoing safety. It is important to review the aircraft’s maintenance schedule to ensure it is appropriate for the aircraft and that it adequately provides for the continuing airworthiness of the aircraft.
In 2007, the ATSB released research report B20050205 - How Old is Too Old? The impact of ageing aircraft on aviation safety. The report found that some aircraft manufacturers have recognised that the original maintenance schedules may not be sufficient to ensure the aircraft’s (ongoing) safety and have developed supplementary inspection programs (such as the Cessna SIDs); other aircraft do not have the same level of airworthiness support. The report concluded that adequate maintenance of ageing aircraft requires the participation and ongoing cooperation of aircraft manufacturers, regulatory authorities, owners, operators and maintainers.
In addition, further information is detailed in CASA’s Ageing Aircraft Management Plan (AAMP).
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
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On 7 October 2014, a Robinson R44 helicopter, registration ZK-HBQ, collided with terrain in the Kahurangi National Park, near Nelson, New Zealand.
The New Zealand Transport Accident Investigation Commission (TAIC) is conducting an investigation into the circumstances of the accident. As part of its investigation, TAIC requested technical assistance from the Australian Transport Safety Bureau (ATSB) in the recovery of data from a damaged GPS unit recovered from the wreckage. To protect the information supplied by TAIC to the ATSB and the ATSB's investigative work to assist TAIC, the ATSB initiated an investigation under the Transport Safety Investigation Act 2003.
The ATSB successfully recovered data from the GPS unit and has provided the data to TAIC to assist with their investigation.
Enquiries relating to the accident investigation should be directed to TAIC at: www.taic.org.nz
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Released in accordance with section 25 of the Transport Safety Investigation Act 2003.
On 31 October 2014, the pilot of a de Havilland DHC-2 aircraft, registered VH-AWD (AWD), conducted a scenic charter flight from Hayman Island Water Landing Area, Queensland. The pilot of AWD broadcast on the common traffic advisory frequency (CTAF) when passing Pinnacle Point. The broadcast from AWD was heard by the pilot of a Gippsland Aeronautics GA-8 aircraft, registered VH-NOQ (NOQ), which had departed from Shute Harbour Airport for a scenic charter flight. Although he heard the broadcast, the pilot of NOQ did not know where Pinnacle Point was as it was not labelled on the visual terminal chart (VTC).
The pilot of NOQ broadcast on the CTAF after passing Tongue Point and heading south along Whitehaven Beach. The pilot of AWD heard a broadcast on the CTAF, possibly that of the pilot of NOQ at Tongue Point, but did not hear the contents of the broadcast. As he missed the broadcast, the pilot of AWD then broadcast his position and intentions, and did not receive a response.
NOQ tracked to the southern end of Whitehaven Beach, turned and headed north returning to Tongue Point. When just south of Tongue Point for the second time, the pilot of NOQ broadcast on the CTAF and advised that he was changing to Hamilton Island air traffic control (ATC) Tower frequency. The pilot then commenced a left turn, selected the Tower frequency and was no longer monitoring the CTAF.
At about 1354 Australian Eastern Standard Time, and 1,300 feet, when approaching Tongue Point from Dumbell Island, the pilot of AWD sighted NOQ on a reciprocal track and estimated the aircraft passed on his right about 50 m away and about 50 feet above AWD.
This incident highlights the importance of broadcasting radio calls on, and monitoring, the appropriate frequency, to alert pilots and assist in see-and-avoid practices. It serves as a reminder to keep a good lookout for other aircraft, particularly around high traffic areas and radio frequency zone boundaries.
On 9 April 2014, a Quest Aircraft Company Kodiak 100 registered PK-SDF collided with terrain during take off from Doyo Baru Airstrip, Jayapura, Papua Indonesia. The accident destroyed the aircraft and fatally injured the two occupants.
The National Transportation Safety Committee (NTSC) of Indonesia is responsible for investigating this accident. The aircraft was fitted with advanced cockpit instrumentation that included a flight data logging function. Although subjected to significant fire damage, the cockpit instrumentation and associated avionics were recovered by on site investigators and transported to the NTSC facilities for further examination. Examination of the instruments revealed remnants of non-volatile memory devices that were fitted to the cockpit displays.
The NTSC requested specialist assistance from the Australian Transport Safety Bureau (ATSB) to attempt the recovery of flight data from the non-volatile memory chips fitted to the cockpit instrumentation.
In accordance with clause 5.23 of Annex 13 to the Convention on International Civil Aviation (ICAO Annex 13) the ATSB appointed an Accredited Representative to assist the NTSC and initiated an investigation under the Australian Transport Safety Investigation Act 2003.
Examination of the instrument display components indicated they had suffered significant heat exposure resulting in the memory device packaging melting. The examination revealed parts of the memory device were present in the display components, however the memory chip could not be located. Consequently no accident flight data could be recovered to assist the NTSC investigation team. Preliminary results were conveyed to the Head of Aviation Sub Committee and a final report provided in November 2014.
The National Transportation Safety Committee of Indonesia is responsible for releasing a final investigation report regarding this occurrence. Contact details for the NTSC are:
National Transportation Safety Committee Office
Ministry Of Transportation Republic Of Indonesia Transportation Building 3rd Floor Jalan Medan Merdeka Timur No. 5 Jakarta Pusat 10110 Indonesia
On 27 October 2014, at about 1030 Eastern Daylight-savings Time (EDT), a Cessna 172 aircraft, registered VH-ZZD departed Ballarat, Victoria, for Luskintyre, New South Wales, on a private flight under the visual flight rules. The pilot refuelled at Wangaratta, Victoria, and took a break for refreshments at Temora, New South Wales. As he neared Kandos, New South Wales, the pilot elected to track directly to Luskintyre, rather than follow his planned route which took him over a number of towns further north.
The direct track between Kandos and Luskintyre was over heavily treed and undulating terrain, leaving the pilot unable to positively visually fix his position. As he continued in an easterly direction, the pilot grew increasingly concerned about the possibility of infringing controlled airspace further to the east. Rather than risk infringing controlled airspace, the pilot decided to make a precautionary landing to ascertain his position. The pilot commented that precautionary landing options were very limited, but he ultimately selected a paddock that was clear of obstacles, and while relatively short, it offered an uphill landing run to assist in stopping the aircraft.
During his approach to land on the selected paddock, with full flap selected, the pilot found himself overshooting the selected aim point. Concerned that he would not be able to land safely, the pilot elected to discontinue the approach and commenced a go-around. As the go-around proceeded however, the aircraft collided with a line of trees on rising terrain beyond the far end of the selected paddock. The aircraft was substantially damaged, and the pilot received serious injuries. The aircraft wreckage was discovered by a local resident around 2 hours after the accident, independent of other search and rescue activities.
Pilots unsure of their position or requiring navigational assistance, are encouraged to seek Flight Following services from ATC. In this case, contact with ATC may have allayed the pilot’s concerns about the prospect of infringing controlled airspace, and negated the need to consider a precautionary landing. With respect to precautionary landings, pilots are encouraged to initiate an early go-around given any doubt regarding the prospects of a safe landing.
On 23 June 2014, a Eurocopter Deutschland BO-105 helicopter, registration P2-NHW, was conducting village-to-village sling-load operations in mountainous terrain in Morobe Province of Papua New Guinea. While on approach to land at the remote village of Onggake, the helicopter’s number-one engine sustained a power loss that required the pilot to conduct a forced landing. There were no injuries. On-site examination of the helicopter revealed that significant internal damage had occurred to the compressor assembly from the number-one engine, a Rolls-Royce M250-C20B turboshaft.
The Papua New Guinea Accident Investigation Commission (PNG AIC) commenced an investigation into the accident and subsequently, technical support was requested from the Australian Transport Safety Bureau (ATSB) in the examination of the compressor assembly. In providing this support, the ATSB commenced an external investigation under the Transport Safety Investigation Act 2003.
The initial disassembly and examination of the compressor was conducted at the ATSB’s technical facilities in Canberra. The parts were subsequently sent to the engine manufacturer in the United States for detailed metallurgical examination. Reports from both the engine manufacturer and the ATSB were provided to the PNG-AIC to assist with the investigation.
The PNG Accident Investigation Commission is responsible for and will administer the release of the final investigation report into this accident.
Further information regarding the occurrence can be found at www.aic.gov.pg or specific enquiries should directed to infor@aic.gov.pg.
