On 12 September 2013, a twin-engine Beech Aircraft Corporation, Model 200 Super King Air was conducting a passenger charter flight from Utirik Atoll to Marshall Islands International Airport (Majuro Atoll). About 40 minutes into the flight, while in cruise to the destination, the pilot observed abnormal oil pressure indications for the left engine and approximately 2 minutes later the engine failed. The crew secured the engine and elected to continue with the original flight plan. The aircraft landed at Majuro Atoll without further incident.
What the ATSB found
Failure of the left engine, a Pratt and Whitney Canada PT6A-41, resulted from fatigue cracking and breakdown of the first-stage sun and planet gears in the propeller reduction gearbox. The specific factors contributing to the initiation of the gear breakdown could not be positively identified; however, the ATSB identified certain PT6A-38, -41, -42 and -42A engines that, while in compliance with applicable maintenance requirements, could be operating with first-stage reduction gears in excess of the manufacturer’s recommended maximum 12,000 hour service life. This specifically related to engines that had not been overhauled since September 1999, when it became mandatory to replace the reduction gears during every engine overhaul. The engine manufacturer has indicated that, provided the engine is maintained in accordance with the applicable instructions for continuing airworthiness, the rate of engine failure associated with high‑time gearsets is extremely remote and that immediate action is not warranted in these situations.
It was also reported that the magnetic chip detector cockpit warning light did not illuminate and that the associated circuit breaker had popped. There have been similar reports of Beech 200 aircraft with popped circuit breakers accompanied by momentary or no chip detector light illumination, shortly preceding engine failure. A previous situation of accelerated engine failure, involving a large volume of liberated engine material bridging the chip detector terminals, was reported to have caused the circuit breaker to pop, precluding the illumination of the warning light. A similar scenario was considered likely in this occurrence.
Safety message
Pratt and Whitney Canada PT6A-38, -41, -42 and -42A engines last overhauled prior to September 1999 may be operating with high-time first-stage reduction gears which have an increased susceptibility to deterioration. Current maintenance procedures may be effective in identifying gradual deterioration of reduction gears, but not necessarily impending rapid, catastrophic breakdown per the subject engine failure. The ATSB therefore encourages operators and maintainers of affected engines to review their maintenance records and give consideration to the replacement of high-time gearsets.
Additionally, pilots and operators should also be aware of the potential for reduction gearbox chip detector cockpit annunciator lights to only illuminate momentarily or not at all, due to short circuits caused by the rapid accumulation of liberated gearbox material, in situations of accelerated engine failure. Even a momentary indication could be an indicator of engine deterioration and therefore should be noted for subsequent maintenance attention.
Occurrence summary
Investigation number
AO-2013-154
Occurrence date
12/09/2013
Location
277 km NNW of Marshall Islands International Airport (Majuro Atoll)
On 22 February 2014, the pilot of a Robinson R44 helicopter, registered VH-UGR, was conducting aerial agricultural operations on a property near Yass, New South Wales.
After successfully completing five loads of spraying, the helicopter was refuelled and reloaded with chemical for the next flight. The wind at the time was light and variable but favouring a southerly direction and the pilot manoeuvred the helicopter to take off towards the south. During the take-off, when at about 3 ft above ground level (AGL), the pilot reported that the helicopter was not climbing as expected and he thought that the wind had veered to a more westerly direction.
He commenced a right pedal turn towards the west, and down the slope, in an attempt to gain translational lift. The pilot reported that the wind had actually turned more easterly, and the helicopter therefore had a tailwind.
The low rotor revolutions per minute (RRPM) warning horn sounded and the pilot jettisoned the chemical load. The helicopter was then about 5 ft AGL, and the pilot was attempting to gain lift, and concentrating on keeping the helicopter straight in order to keep the landing skids level. He sighted a dry creek bed ahead and attempted to gain altitude prior to crossing it.
The helicopter was about 40-50 m beyond where the load had been jettisoned, and the pilot was focused on gaining lift, when the left skid contacted the ground, and the helicopter rolled over.
This incident highlights the importance of assessing options in case of reduced aircraft performance on take-off.
On 23 February 2014, a Hughes 269C helicopter, registered VH-HAK, was parked on a property about 55 km north-east of Launceston, Tasmania, beside a dam. The pilot had shut the helicopter down in that position about a week earlier, aware that it was low on fuel.
At about 0700 Eastern Daylight-savings Time (EDT), the pilot prepared for a short 200 m flight to reposition the helicopter to the other side of the dam, for refuelling. He conducted fuel drains, with no contaminants found.
The helicopter took off and climbed to about 20 ft above ground level. When about three quarters of the way across the dam, the engine stopped due to fuel exhaustion. The pilot conducted a forced landing onto the edge of the dam, with part of the helicopter sinking into the water and mud. The main rotor blades collided with the embankment resulting in substantial damage.
While experience and familiarity with operations are invaluable, they can also lead to complacency. It is therefore important that pilots with experience, familiarity and comfort with the aircraft and location, continue to do all checks thoroughly.
On 21 February 2014, the pilot of a Piper PA-28R aircraft, registered VH-TBB, departed Scone, New South Wales on a private flight to Warwick, Queensland. The flight was planned under the visual flight rules (VFR). The planned route took the aircraft overhead Tamworth and Inverell, then on to Warwick.
The flight proceeded normally until the pilot encountered an increasing amount of cloud and light rain showers while en route between Inverell and Warwick. The pilot initially attempted to pass beneath the cloud, but had difficulty maintaining visual meteorological conditions (VMC). Although the cloud appeared to be relatively light with ill-defined edges, the pilot found that forward visibility was restricted.
The pilot advised air traffic control (ATC) that he was occasionally encountering instrument meteorological conditions (IMC), and with the aircraft intermittently identified on radar, ATC was able to assist the pilot with relevant advice. About 30 NM from Warwick, the pilot reported clear of the weather, and the flight continued without further incident.
The pilot later indicated that during the intermittent encounter with marginal conditions, the aircraft was in cloud for a total time of about one minute. The pilot had undertaken some instrument flight training about 2 years prior to the incident, which provided some confidence with respect to aircraft control during his encounter with marginal conditions.
Pilots are encouraged to make conservative decisions when considering how forecast weather may affect their flight. If poor weather is encountered en-route, timely and conservative decision making may be critical to a safe outcome. VFR pilots are also encouraged to familiarise themselves with the definition of VMC criteria, and carefully consider available options where forecast or actual conditions are such that continued flight in VMC cannot be assured.
The ATSB SafetyWatch highlights the broad safety concerns identified in investigation findings and from safety data reported to the ATSB by industry. One safety concern relates to general aviation pilots who fly into conditions of reduced visibility, without the appropriate training, skills and qualifications. The ATSB research report Avoidable Accidents No 4 – Accidents involving Visual Flight Rules pilots in Instrument Meteorological Conditions provides some key messages with respect to weather-related general aviation accidents.
On 8 February 2014, at about 1500 Eastern Daylight-savings Time, the pilot of an AMS-Flight DG-303 glider, registered VH-DGA (DGA), broadcast on the local gliding club radio frequency that he would return to land at Bunyan aeroplane landing area (ALA), New South Wales, following a local flight of about 90 minutes duration. The glider was about 5 NM east of the aerodrome and on descent from 10,000 ft above mean sea level (AMSL).
About 10 minutes later, the pilot of a Piper PA-25, registered VH MLS (MLS), broadcast a lining up and rolling call and took off from runway 33 at Bunyan to launch a glider from overhead the aerodrome. At about 1515, when at about 4,000 ft AMSL, in anticipation of the glider pilot releasing the tow cable, the pilot of MLS turned to look behind the aircraft. He confirmed that the glider had released successfully and in accordance with standard operating procedures he then commenced a descending turn to the left.
The pilot of DGA sighted MLS release the glider and commence the turn. As the two aircraft were at about the same altitude and he then observed MLS with the wings level, he assumed the aircraft would then track straight ahead. He commenced a right turn to increase separation between them, and to track towards the joining point for a right downwind for runway 27. He reported that he assumed the pilot of MLS had sighted DGA at that time, and that he did not see MLS again until it was on downwind.
As the pilot of MLS rolled the aircraft’s wings level from the turn, he saw DGA as a white flash passing about 30 ft below him, and reported that he could see the rivets on the glider’s airbrakes.
This incident highlights the importance of communication and the limitations of unalerted see-and-avoid principles.
On 20 February 2014, at about 0605 Eastern Standard Time (EST), a Bell 206B helicopter, registered VH-BNG, took off from a banana plantation to conduct aerial spraying.
The pilot conducted pre-application checks including assessing the wind strength and direction, the position of the sun, identifying the area to be sprayed and any hazards.
The block was to be sprayed as soon as possible after first light and the pilot planned to conduct the spraying in an east-west direction. After about 5 minutes of spraying, some overspray accumulated on the windscreen, resembling a white paint. The pilot then noted that the on-board smoke generator indicated the wind had changed direction, so he flew the helicopter to the southern end of the block and resumed spraying into wind.
After completing spraying, the pilot commenced a return to the staging area. To comply with local noise abatement procedures, the pilot climbed the helicopter to about 250-300 ft above ground level (AGL) and established a flight path to avoid overflying noise-sensitive areas.
At about 0615, on descent to the staging area, when at about 150-200 ft AGL, the helicopter rotor blades collided with a tree, dislodged a branch, and the helicopter subsequently collided with terrain. The helicopter was substantially damaged, and the pilot sustained serious injuries.
On 20 February 2014 at 1425 EDT, a Fairchild Industries Metro 23 aircraft, registered VH-UUB, was being operated on a charter flight from Avalon to Portland, Victoria with 10 passengers and two crew on board. Shortly after touch-down the torque link on the left, main landing gear (MLG) failed. The aircraft veered left as a result, and came to rest beside the runway. There were no injuries as a result of the occurrence.
What the ATSB found
The runway excursion resulted from failure of the lower torque link attachment lug on the left main landing gear’s yoke. This allowed the wheels to rotate through 90° with respect to the direction of aircraft travel and skid, producing a large braking effect on the left side. The flight crew were unable to counteract this and it resulted in the aircraft veering to the left and off the runway.
The failure of the lug on the yoke resulted from pre-existing cracks that had progressively grown until the part had insufficient strength to support normal landing loads. The cracks initiated principally from areas of pitting corrosion in the lug’s bore and were propagated by cyclic stresses imposed during operation.
The ATSB identified a safety issue whereby the maintenance and inspection program for the aircraft’s landing gear did not adequately provide for the detection of corrosion and cracking in the yoke lug bore.
What has been done as a result
The Civil Aviation Safety Authority (CASA) has released Airworthiness Bulletin AWB 32-023 to alert all Fairchild Swearingen Metro and Merlin operators of the need for detailed inspection of the internal bore of the landing gear torque link lugs for any signs of corrosion or wear outside of the manufacturer’s specified limits and to take appropriate action per the aircraft’s structural repair manual, where necessary.
In addition, the aircraft’s Type Certificate Holder has drafted service bulletins 226-32-083, 227-32-065, CC7-32-030 titled “inspection of Main Landing Yoke for Corrosion and/or Damage” that will significantly increase the effectiveness of maintenance inspections for the affected parts.
Safety message
This occurrence highlights the importance of developing and conducting appropriately detailed maintenance inspections on susceptible parts and assemblies.
UBB after veering off the runway
Source: airline operator
Findings
From the evidence available, the following findings are made with respect to the runway excursion involving a Fairchild Metro 23 aeroplane, registered VH-UUB, which occurred at Portland, Victoria on 20 February 2014. These findings should not be read as apportioning blame or liability to any particular organisation or individual.
Safety issues, or system problems, are highlighted in bold to emphasise their importance. A safety issue is an event or condition that increases safety risk and (a) can reasonably be regarded as having the potential to adversely affect the safety of future operations, and (b) is a characteristic of an organisation or a system, rather than a characteristic of a specific individual, or characteristic of an operating environment at a specific point in time.
Contributing factors
The runway excursion occurred as a result of fracture of the torque-link attachment lug on the aircraft’s left main landing gear yoke, which allowed those wheels to deviate from the normal direction of travel and cause asymmetrical braking forces that could not be countered by the flight crew.
The torque link-to-yoke attachment lug fractured under normal operational loads as a result of the initiation and propagation of fatigue cracks originating at areas of excessive wear and corrosion pitting on the lug bore.
The maintenance program for the aircraft’s landing gear did not adequately provide for the detection of corrosion and cracking in the yoke lug bore. [Safety issue]
Context
Main landing gear description
The main landing gear assembly is composed of a telescoping upper cylinder (strut), a piston assembly and, at the lower end, the yoke (Figure 3). A torque link assembly connects at lugs on the strut and the yoke, allowing compression of the assembly while preventing rotation of the yoke. In this occurrence, the lug on the yoke had fractured.
Yokes in the MLGs of earlier SA227 models were manufactured by Ozone Industries as part number (P/N) OAS5453005-5[3]. In later models, manufacture was by another landing gear vendor, Klune Industries, and started with the fabrication of the 27-series part numbers. The fractured yoke from VH-UUB was identified as P/N 2751505005, manufactured by Klune Industries.
Source: M7 Aerospace SA227 Maintenance Manual (Modified by ATSB)
Recorded information
The ATSB downloaded and analysed data from the aircraft’s Flight Data and Cockpit Voice Recorders (FDR & CVR, respectively). The data confirmed that following touchdown, the aircraft began veering to the left. Approximately 8 seconds later, the aircraft departed the runway. In addition, the following points were noted:
The vertical speed prior to landing was that of a normal approach.
Vertical decelerations recorded during the touch-down were not excessive.
The airspeed at touch-down was consistent with prior flights.
The aircraft was correctly configured for landing.
Component Examination
Lug Fracture
The aluminium torque link and yoke were assembled via a steel torque link shaft (TLS) that mated with bronze bushes in the lower link. It was secured with a single, stainless-steel retaining (spring) pin with stainless steel lockwire in its bore (Figure 4).
The fractured yoke contained four disused retaining pin holes (two each top and bottom) as a result of compliance with a service bulletin (SB) for installing a replacement TLS (CC7-32-012), released in 2002. The SB required drilling of a new pin hole in the lug to secure the replacement TLS and filling of the redundant holes with sealant. As examined, the disused holes in the fractured yoke were not sealed, but instead contained black corrosion/wear product. However, traces of sealant around some of the holes suggested that they had probably been filled at the time of service bulletin compliance.
Figure 4: Lower torque link attachment assembly with fractured lug segment in-situ
Source: ATSB
Significant corrosion pitting was evident in the bore of the lug and on the lug flanks, with concentrations around the four disused, spring pin holes (Figure 5). Fatigue crack progression (beach) marks were identified on the lug fracture surfaces with the crack origins located at areas of significant corrosion pitting and wear in the bore. The fatigue cracking progressed across most of the lug cross section before the remaining portion fractured by ductile overstress. The overstress areas were largely defined by a narrow region on the outside radius of the lug (furthest from the bore).
Detailed examination of the corrosion pits adjacent to the fracture surface found evidence of corrosion product as well as a series of crack progression marks radiating outwards from the edge of the corroded areas.
Figure 5: Yoke lug exhibiting corrosion pitting, wear in the bore and fatigue crack progression on the fracture surfaces (main crack origins arrowed)
Source: ATSB
Lug dimensions
The bronze bushes installed in the lower torque link had worn against the yoke’s lug flanks during normal operation such that, in the areas of greatest wear, the width of the lug was now 66.03mm (2.6”) which was 0.26mm (0.01”), below the minimum dimension of 2.61” (66.294mm) specified in the structural repair manual (Figure 5).
Material properties
The material properties were correct for the specified 7075-T73 aluminium alloy. Electrical resistivity testing showed that a majority of the chromic acid anodised coating, applied to the component during manufacture, had worn away, increasing the component’s susceptibility to corrosion and wear, particularly in an aqueous environment of metals dissimilar to aluminium.
Figure 6: Flank of the fractured yoke lug showing surface wear from mating bush
Source: ATSB
Yoke maintenance requirements
The Fairchild MLG yokes were maintained on condition and were not subject to any maximum service life restrictions. At the time of the occurrence, the SA227 Phase Inspection Manual (SA227 CC/DC Commuter Category, Rev 19, Sept 28, 2012) included requirements for inspection of the aircraft structure and components. The definitions section of the manual stated that;
A routine inspection – Visual inspection not requiring removal of access panels or fairings.
A detailed inspection – Detailed inspection requiring removal of access panels, doors, fairings, covers, upholstery and components for inspection.
The aircraft was maintained using a 6-phase inspection program with an interval of 900 hours; this included a detailed inspection of the main landing gear at a phase 3 inspection (450 hours) and a routine inspection at a phase 6 inspection (900 hours).
The phase inspection manual also included a section which included a list of requirements for the routine and detailed inspections. The detailed inspection included the requirement to inspect struts for damage, evidence of leakage, condition and security, and to inspect scissors and bushings for wear, condition and security. The manufacturer advised that in order to perform these inspections, the shaft attaching the scissor links to the yoke lug should be removed and the condition of the components checked, as well as the wear limits.
The most recent detailed (Phase 3) inspection was 436.5 hours prior to the occurrence, and a routine (Phase 6) inspection 37.3 hours prior to the occurrence. The operator’s inspection procedures followed the guidelines in the inspection manual and there was no record of the components being disassembled at either inspection. The operator advised that they performed a torque link freeplay inspection at the detailed inspection and if excessive freeplay was evident, then the components would be disassembled for further inspection.
In August and September 1995, Fairchild issued two service bulletins to cover six of the earlier SA227 models equipped with Ozone MLG & NLG (Nose Landing Gear) yokes. This was due to failures initiated by stress corrosion cracking and corrosion fatigue. In those occurrences, the failure origin was at the forging die parting (flash) line in the upper yoke area, where the piston was shrink-fitted. Both the Federal Aviation Administration and the Civil Aviation Safety Authority issued airworthiness directives a month later.
Other occurrences
On 10 June 2007, an SA227-DC, registered VH-HPE, sustained a left MLG yoke lug failure during post-landing taxiing at Tennant Creek Aerodrome. The ATSB did not investigate that occurrence, however a report provided to the ATSB indicated that the fracture similarly related to fatigue crack progression precipitated by wear, corrosion pitting and stress corrosion cracking in the yoke lug bore.
The Civil Aviation Safety Authority (CASA) were aware of four Australian-registered, SA227 MLG torque link lug failures, as well as cracking of a yoke lug, found during daily inspection, on a Canadian-registered aircraft.
The manufacturer advised they were aware of two cracked yoke lugs, which were found by the same Canadian operator in 2012. A failure analysis report for one of the failures showed similar cracking to that identified on UUB. The report stated that the failure occurred as a result of cracking that had initiated at multiple corrosion pits on the inner surface of the lug. In this case however, the cracking had propagated to the external surface, which allowed it to be identified during a daily maintenance inspection. The same Canadian operator also experienced a third failure in December 2015, which was identified by the flight crew after landing.
Sources of information used during the investigation included:
the aircraft’s type certificate holder
the aircraft operator
the Civil Aviation Safety Authority
the operating flight crew
the aircraft’s flight data recorders.
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 the operator, the aircraft maintenance provider, M7 Aerospace and CASA.
Submissions were received from the operator, M7 Aerospace and CASA. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.
The occurrence
On 20 February 2014, a Fairchild Industries SA227-DC ‘Metro 23’ aircraft, registered VH-UUB, had been flown from Avalon to Portland, Victoria on a charter flight. On board were two flight crew and 10 passengers. A normal approach was conducted and the aircraft touched down at 1425 EDT[1]. During the landing roll, the flight crew noted the aircraft began veering to the left. The flight crew attempted to counteract the movement, using rudder inputs, reverse thrust on the engines and the right brake, but the aircraft subsequently departed the runway at a speed of 75 to 80 knots and began to slide sideways. The left main landing gear (MLG) dug into the ground and the nose of the aircraft swung sharply to the left as it came to a stop. The flight crew shut the aircraft down and disembarked the passengers when it was safe to do so. There were no reported injuries as a result of the occurrence.
Subsequent inspection of the aircraft found that the torque link[2] had detached from a fractured lug on the lower section of the left MLG (arrowed in Figure 1b), allowing the wheel assembly to rotate through 90° w.r.t. the direction of aircraft travel. This resulted in skidding wheels, producing a significant braking effect on the left main gear and causing the aircraft to veer to left and depart the runway (Figure 2).
Figure 1: Damage to the left MLG
Source: Airline operator
Figure 2: Damage to runway as a result of contact with the left main landing gear following failure
The runway excursion involving Fairchild Industries Metro 23 VH-UUB at Portland, Victoria, on 20 February 2014, was the result of the failure of a lug on yoke of the wheel assembly on the left main landing gear (MLG) during the landing roll. The failure of the lug disconnected the torque link between the upper MLG strut and the lower wheel assembly; this allowed the wheel assembly to rotate through 90° with respect to the direction of travel. This effectively resulted in a large braking force on the left side of the aircraft. The flight crew were unable to counteract that asymmetric braking force and as a result, the aircraft veered off the runway
Failure of the MLG yoke lug
The yoke lug fractured as a result of a fatigue cracking mechanism with crack initiation points located in the bore of the lug at areas of significant wear and corrosion pitting. The fatigue crack progressed through most of the lug cross section before final fracture during the occurrence landing.
Corrosion pits act as stress concentrators and significantly reduce both the fatigue crack initiation life of the component as well as the crack initiation threshold stresses. The corrosion, wear and cracking had likely been present in the lug bore for a significant period of time prior to failure occurring. Early indications of corrosion and cracking on the lug bore would not have been visible during the inspections prescribed in the inspection manual, without first disassembling the affected parts. Neither the detailed nor routine inspections explicitly required an inspection of the lug bore, although the manual contained a general definition of a detailed inspection that required components to be disassembled for examination. The list of required inspection items also implied that some disassembly would be required to adequately inspect various components. The operator indicated that while no disassembly was performed, a torque link freeplay inspection was performed which would have led to further examinations if anomalies, such as excessive movement, were found.
There were several factors that influenced corrosion of the yoke lug bore. Sealing of the disused pin holes in this occurrence was not adequate as the sealant had either broken down over time or otherwise disbonded and come loose during service, providing additional entrance routes for moisture or other corrosives. Another entrance route was associated with wear on the yoke lug flanks where significant pitting was identified. Wear on the flanks and in the bore of the lug was sufficient to remove the protective anodic coating, which increased the susceptibility of the parts to corrosion. With corrosion pitting being a precursor to the fatigue failure of the component, improvement of corrosion protection in the affected areas would further reduce the likelihood of this type of occurrence.
Safety issues and actions
The safety issues identified during this investigation are listed in the Findings and Safety issues and actions sections of this report. The Australian Transport Safety Bureau (ATSB) expects that all safety issues identified by the investigation should be addressed by the relevant organisation(s). In addressing those issues, the ATSB prefers to encourage relevant organisation(s) to proactively initiate safety action, rather than to issue formal safety recommendations or safety advisory notices.
Depending on the level of risk of the safety issue, the extent of corrective action taken by the relevant organisation, or the desirability of directing a broad safety message to the aviation industry, the ATSB may issue safety recommendations or safety advisory notices as part of the final report.
Where relevant, safety issues and actions will be updated on the ATSB website as information comes to hand. The initial public version of these safety issues and actions are in PDF on the ATSB website.
Safety issue title – Inadequate inspection procedures
The maintenance program for the aircraft’s landing gear did not adequately provide for the detection of corrosion and cracking in the yoke lug bore.
Purpose of safety investigations & publishing information
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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.
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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.
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On 19 February 2014, at about 1030 Eastern Daylight-savings Time, a Beech A36 (Bonanza) aircraft, registered VH-EUB, departed Lilydale aeroplane landing area (ALA), Victoria, for a training flight, with an instructor and pilot-under-instruction on board.
While the crew were completing training exercises in the local area, a storm cell with heavy rain passed over the airport. The pilot then broadcast an inbound call and returned to Lilydale, joining downwind for a landing on runway 18 Left (18 L). The pilot conducted pre-landing checks and confirmed that the brakes had pressure. He observed that the windsock indicated runway 18. The aircraft arrived over the runway threshold about 50 ft above ground level at about 85 kt indicated airspeed. This was slightly higher and faster than an optimal approach.
The aircraft touched down about 250-300 m along the runway and the pilot applied the brakes, however the aircraft did not decelerate. The instructor took over the control of the aircraft and commenced applying the brakes, then releasing and reapplying them. The brakes remained ineffective at gaining traction. At this stage the instructor assessed that it was too late to commence a go-around, and that the aircraft was aquaplaning on the wet runway.
With less than 100 m of runway remaining, the pilot and instructor both applied right rudder in an attempt to steer the aircraft away from an embankment located about 20 m beyond the end of the runway. The aircraft rotated 90° to the right and continued to slide in the direction of the runway. The aircraft came to rest on top of the embankment and the left main landing gear collapsed.
After exiting the aircraft, the instructor observed that the wind had veered and that a tailwind may have contributed to the incident.
This incident highlights the importance of conducting a go-around as soon as landing conditions appear unfavourable.
On 17 February 2014, a Cessna C206 aircraft, registered VH-YOT, departed runway 05 at Newman Airport, Western Australia, at about 0526 Western Standard Time for a charter flight to Cotton Creek in visual meteorological conditions. The pilot was the only occupant.
About 3 minutes after take-off, while in the climb and at about 1,500 feet above ground level the pilot conducted a scan of the aircraft instruments and noticed that the engine oil pressure gauge was indicating zero. All the other engine instrument indications were in the normal range. The pilot turned the aircraft back towards Newman airport. About 1 minute later the pilot observed sparks coming from the engine cowling near the propeller, the engine power decreased and a severe vibration was felt through the airframe. The pilot pulled the mixture control to lean cut off to stop fuel flowing to the engine as he was concerned about an inflight fire and the propeller stopped rotating.
The pilot determined that he would not be able to glide to runway 23 and began a scan to locate a suitable landing area. The pilot located a paddock that was about 4 km from the airport that appeared to be a suitable landing area and was near a dirt road. Prior to landing, the pilot shut down all non-essential aircraft systems.
On landing, the left wing impacted a tree and the aircraft spun around 180 degrees. The pilot shut down all remaining systems and climbed into the rear section of the aircraft. The pilot exited the aircraft through the rear section of the cargo door and was not injured. The aircraft was substantially damaged.
This accident highlights the importance of 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, conducting a thorough pre-flight and engine ground run to identify any issues that may lead to an engine failure and 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.
On 18 February, 2014 an instructor from a local flying school at Moorabbin Airport, Victoria, conducted a trial instructional flight (TIF) in a Cessna 150, registered VH-RXM.
As the aircraft taxied to the runway holding point, ATC advised of a 3-4 knots tailwind on the duty runway, 35 Left (L). Although the wind was now southerly, the instructor was satisfied it was still acceptable to safely depart on this runway.
The flight was intended to give the student a “hands-on” experience at flying an aircraft. During the take-off, the student slowly advanced the throttle to attain full power, and then applied back pressure to the control column during the rotation and initial climb. These actions were monitored by the instructor. To enhance the “flight experience” for the student, the instructor had minimal input. He did however, maintain full control of the rudder pedals, and took control of the throttle lever once the student had applied full power.
During the initial climb, the student continued to apply back pressure to the control column resulting in a reduction in optimal airspeed, and a higher than normal aircraft nose attitude. As the instructor attempted to rectify the aircraft’s profile, the right wing dropped and the aircraft began to descend.
The instructor’s efforts to recover the aircraft to a normal climb attitude were not successful, and the right side of the aircraft struck the ground. The aircraft bounced, then came to a halt on its left side.
The instructor and student egressed through the right door. They both sustained minor injuries. The aircraft was substantially damaged.
As a ‘Safety Action’, the flying school have changed their procedure in regard to trial instructional flights.
Instructors will now complete the take-off and initial climb to a height of 300 ft.
