Collision with terrain

What happened

On 7 July 2018 at 0915 Eastern Standard Time, a Victa Airtourer with two crew was on a private flight from Kilcoy, Queensland (Qld) to a private grass airstrip near Somerset Dam, Qld. Weather conditions were reported as cloud at 2,500 ft with a slight crosswind.

During landing, the pilot landed long on the airstrip which was made up of wet grass. The pilot considered conducting a go-around or conducting a controlled ground-loop^[1]. The pilot briefly opened the throttle to attempt the go-around, but quickly closed it as the aircraft was reaching the end of the strip.

The aircraft overran the strip and collided with a barbed wire fence. After shutting down the aircraft, both occupants evacuated uninjured.

The aircraft was assessed to have sustained extensive damage including to the left-wing leading edge, right aileron, bent propeller blades and a torn off landing gear and nose wheel.

Contributing factors to the overrun include:

• wet grass runway
• minimal wind conditions
• a long touchdown on the strip
• opening the throttle late.

Safety message

When conducting flights into unfamiliar locations, pilots should attempt to research the airstrip or field prior to departure. For private or undocumented strips, conducting a pass over the strip first before landing will aid in determining runway length and characteristics.

In some cases, a wet runway may not be evident prior to landing. Utilising the full length of the strip allows pilots extra time to execute recovery manoeuvres (such as conducting a go-around) from compromising situations such as a wet runway, which can limit an aircraft’s braking abilities.

Additionally, pilots should familiarise themselves with their aircraft operating handbook to build confidence on their decision making in time-critical situations.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

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1. A ground loop is an ‘involuntary uncontrolled turn while moving on the ground, especially during take-off or landing’ (Bill Gunston, The Cambridge Aerospace Dictionary, New York, New York; Cambridge University Press, 2004, p.275).

What happened

On 13 May 2018, a remotely piloted Da-Jiang Innovations (DJI) Phantom 4 aircraft was launched from a lookout near Hope Downs 4 Mine, with the pilot and observer intending to conduct an aerial berm^[1] inspection within one of the mining pits. At about 0735 Western Standard Time, the aircraft lost power and fell to the pit floor, resulting in the aircraft being destroyed.

During the flight, witnesses observed the battery separate from the body of the aircraft and fall to the ground. An inspection revealed hairline fractures around the catch, which locks the battery in place. The recovered battery was also fractured in this area.

Later, it was determined that a post-flight check had not been completed on the previous flight. In addition, the pre-flight inspection of the aircraft just prior to the accident flight had not included a check of the battery connection and locking mechanism.

Safety action

As a result of this occurrence, the remotely piloted aircraft operator has advised the ATSB that they have taken the following actions:

• modifying their procedures to include the recording of all maintenance activities to their sub 2 kg remotely piloted aircraft
• including in their pre-flight checklist that the observer or a secondary person will check the installation of the battery.

In addition, the operator has emphasised the importance of pre and post-flight checks of the aircraft.

Safety message

This accident highlights the importance of pre and post-flight inspection of remotely piloted aircraft. Aircraft manufacturer user manuals, which are generally accessible online, provide specific guidance in relation to each model of aircraft, including information in relation to the correct fitment of the battery. Additionally, the Civil Aviation Safety Authority provides generic guidance in relation to the operation of remotely piloted aircraft and the training requirements of operators on their Flying drones/remotely piloted aircraft in Australia web page.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

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1. Berm is a term used to describe a barrier, such as a wall.

What happened

On 24 March 2018 the pilot of a Cessna 340 was on a private flight from Bankstown, New South Wales to Lilydale, Victoria. The aircraft was operating under the instrument flight rules (IFR)^[1]. The aircraft arrived at Lilydale at 1205 Eastern Daylight-saving Time.

During descent into Lilydale the pilot reported passing through broken cloud and becoming visual with the airfield. The pilot then cancelled IFR and proceeded to overfly the airfield to inspect the runway and windsock. The windsock indicated little wind. There was rain forecast in the area and showers in the vicinity, however there was no rain reported over the airfield at the time of arrival.

The pilot conducted a normal approach and touched down 250-300 m down the 850 m grass runway. After touchdown, the pilot applied moderate braking force. After realising that the aircraft was not slowing, the pilot applied further braking. The aircraft failed to slow and the pilot confirmed the throttles were at idle and pumped the brakes. The aircraft continued to slide down the runway. As the aircraft approached the end of the runway, the pilot applied full left rudder to turn the aircraft which resulted in a slight veer to the left. The aircraft collided with an embankment at the end of the runway, passed over a road and coming to rest against a fence (Figure 1). The aircraft was substantially damaged, and the pilot was not injured.

Post-flight it was determined that the airfield had received significant rain within around 1 hour before the landing which may have resulted in aquaplaning^[2]. The pilot reported that flap was set at 30 degrees for landing, less than the maximum available of 40 degrees. Contributing factors to the overrun include;

• wet grass runway (with possible standing water)
• nil wind conditions
• selection of less than full flap
• touchdown one third down the runway.

Figure 1: Final resting position of the aircraft 

Source: Victoria Police

Safety message

Wet runways present a hazard as the braking ability of the aircraft may be limited, particularly if there is standing water. Pilots should familiarise themselves with the pilots operating handbook for their aircraft and make allowances for runway length, size, slope, construction and condition.

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1. Instrument flight rules (IFR): a set of regulations that permit the pilot to operate an aircraft in instrument meteorological conditions (IMC), which have much lower weather minimums than visual flight rules (VFR). Procedures and training are significantly more complex as a pilot must demonstrate competency in IMC conditions while controlling the aircraft solely by reference to instruments. IFR-capable aircraft have greater equipment and maintenance requirements.
2. Aquaplaning: occurs when a layer of water builds up between the tyres and the runway. This results in loss of traction, preventing effective braking and aircraft control.

What happened

On the morning of 27 March 2018, a Robinson R22 helicopter landed at Delamere Station, Northern Territory (NT) to conduct a refuel from the drum stock.

At about 0730 Central Standard Time (CST), after the refuelling was complete, the pilot proceeded to take-off from the station. During the take-off, the downwash from the main rotor blade spun the fuel pump around the top of the fuel drum resulting in the fuel hose hooking over the helicopter’s skid. The fuel hose subsequently pulled the helicopter to one side causing dynamic rollover.^[1] The helicopter collided with the ground resulting in substantial damage (Figure 1).

Figure 1: Robinson R22 post-accident, in the vicinity of the fuel drum

Source: Operator

Safety message

The pivoting of the helicopter with the skid in contact with the fuel hose, and subsequent loss of control is consistent with the phenomenon known as dynamic rollover.

Once started, dynamic rollover cannot be stopped by application of opposite cyclic^[2] control alone. Even with full opposite cyclic applied; there is not sufficient control authority to arrest the roll once it is developed and the main rotor thrust vector and its moment serves to accelerate the roll. Quickly reducing collective^[3] pitch is the most effective way to stop dynamic rollover from developing.

This occurrence serves as a reminder for pilots to never hover close to fences, sprinklers, bushes, runway lights or other obstacles a skid could catch on.

The R22 Pilot's Operating Handbook includes a safety notice (SN-9) which provides advice about how to avoid dynamic rollover situations.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

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1. Dynamic rollover: A rolling tendency, when close to the ground. For dynamic rollover to occur, some factor has to cause the helicopter to roll or pivot around a skid or landing gear wheel until its critical rollover angle is reached.
2. Cyclic: a primary helicopter flight control that is similar to an aircraft control column. Cyclic input tilts the main rotor disc, varying the attitude of the helicopter and hence the lateral direction.
3. Collective: a primary helicopter flight control that simultaneously affects the pitch of all blades of a lifting rotor. Collective input is the main control for vertical velocity.

What happened

On 25 February 2018, an Aeroprakt A22LS Foxbat departed a station on a flight to observe local floodwaters. At the time of departure, the dirt runway was wet and covered in part by standing water. On return from the local flight, the pilot attempted to land the aircraft on a part of the runway without standing water as close to the station as possible. The aircraft was configured with half-flap on approach and bounced on landing while negotiating the short length. Before applying power to go around, the aircraft impacted heavily on the nosewheel. The aircraft climbed out and the pilot reversed the direction of landing, in order to have greater runway available without standing water when he attempted a second landing. There was no wind at the time.

On touchdown the pilot noticed that the rudder pedals were locked and little control authority was evident. During the ground roll, the aircraft began to veer to the right towards a drum marking the edge of the runway. The pilot increased power with the intention to gain height and avoid the obstacle, and then to climb away so as to ascertain the nature of the control difficulty at a safe height.

The increase in power and upwards pitching movement of the aircraft with a groundspeed below 20 kts increased slipstream^[1], torque^[2] and gyroscopic effect^[3] at a critical phase of flight. The resultant forces rolled the aircraft to the left which could not be corrected with control input before the left wing contacted the ground. The right main undercarriage subsequently impacted a large rock, causing the aircraft to ground loop^[4] and to sustain substantial structural damage (Figure 1)

The pilot sustained minor injuries including bruising and neck pain but was unable to seek immediate medical attention due to the station being isolated by floodwaters.

Figure 1: A22LS Foxbat post-impact

Initial post-flight investigation revealed a suspected cause: a soft water bottle, previously unrestrained on the passenger seat, had lodged under the rudder pedals on the passenger side and hidden from view. Further inspection by the owner the next day revealed that the soft water bottle could not have been the cause. The bottle was trial-fitted under the rudder pedals and rudder movement was established. The pilot reported that the water bottle had most likely lodged under the pedals during the resultant accident sequence.

The pilot identified that the most likely cause of the rudder control difficulty may have come from damage sustained to the nosewheel on the first landing. The A22LS Foxbat has rudder pedal controls that are linked by a series of connecting rods to the nosewheel in order to provide easy steerage on the ground. Damage to the nosewheel assembly may have restricted rudder control input during the second landing.

Safety message

Pilots are reminded that operations from unprepared runways can be hazardous. Particular care should be given to ensure sufficient take-off and landing distance is available to effect safe operation without distraction, especially when hazards exist.

Understanding the low-speed reaction of a particular aircraft in go-around situations is also of particular importance. Safe buffers between take-off safety speed^[5] and rotation for take-off should be maintained in all normal and emergency situations. Accepting a low consequence runway excursion may be preferable to a high consequence loss of control and collision with terrain event.

Pilots and passengers are reminded of the hazard of loose objects in the cockpit, before or during flight. Not only can loose objects distract pilots during critical phases of flight, but they may also lodge in control systems, physically impact pilots and passengers, or create a fire hazard if inappropriately stored.

Pilots should routinely assess environmental and other possible external hazards prior to flight in order to fully understand the risks that may be encountered during the operation.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

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1. Spiralling airflow from the propeller that strikes the side of the vertical fin, most pronounced at high power settings.
2. Rotational reaction opposite to the direction of rotation of the propeller, most pronounced at high power settings.
3. Rotational reaction acting in the yaw axis during a pitch change, due to rotation of the propeller.
4. The aircraft enters a rapid rotation on the ground and spins until it comes to rest.
5. A speed which provides adequate control of the aircraft for flight, normally greater than 1.2 times the aircraft stall speed.

What happened

On 18 January 2018, at 1400 Eastern Daylight-saving Time (EDT), a DJI Matrice 600 Pro hexacopter remotely piloted aircraft (RPA) was conducting a flight above Roseville Chase oval, New South Wales (NSW). During the return-to-home procedure, at a height of 20-25 m, the RPA contacted a pole and subsequently collided with terrain. It sustained damage beyond repair.

The pilot speculated that it is possible that the return-to-home height was not checked after the application was started. This caused the RPA to return to home at an unsafe height.

Safety message

This incident highlights the importance of following pre-flight procedures for remotely piloted aircraft to ensure that all flight parameters are set correctly.

Further information about flying a drone (RPA) safely can be found on the ATSB website, under the news item: Know your drone and the rules to fly safely.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

What happened

On 15 January 2018, at 1245 Eastern Standard Time (EST), a Vans Aircraft RV-7A commenced take-off from runway 15 at Atherton airport, Queensland (Qld) for Charters Towers, Qld. The pilot was the sole occupant.

The pilot reported that upon rotation,^[1] the aircraft encountered a dust devil^[2] and was pushed to the left. The pilot then applied full power in an effort to regain directional control and land the aircraft. The left wing, however, contacted the ground, and the aircraft came to rest inverted. The aircraft was substantially damaged and the pilot received minor injuries.

A row of trees to the left of the runway combined with hot weather was conducive to the formation of dust devils. There was no visual indication of debris or dust plumes to indicate the sudden formation or location of the dust devil, causing difficulty in identification and avoidance measures.

Figure 1: Vans Aircraft RV-7A post-accident, including damage to the left wing

Source: Queensland Police Service

Safety message

The ATSB has investigated multiple take-off and landing accidents associated with dust devils, including Loss of Control; Mt Vernon Station, WA; 1 September 2006; VH-RIL, Cessna 172L (200605133), which highlights the risk of this phenomenon and how light aircraft may be affected. Further information on The Dangers of Dust Devils is available on the ATSB website.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

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1. Rotation: The action of raising the nose wheel by applying back pressure to the yoke.
2. Dust devil: A dust filled vortex similar in shape to a tornado but of much less strength. Source: Bureau of Meteorology

What happened

On 10 February 2018, the pilot of an American Champion Aircraft 7GCBC was conducting solo circuit training at Orange, New South Wales (NSW), on the unrated cross runway 04, which has a grassed red clay surface.

At 0930 Eastern Daylight-saving Time (EDT), during a touch-and-go landing in gusty wind conditions, the aircraft landed hard and bounced. After the aircraft bounced a second time, the pilot applied power and attempted to go-around but during the initial climb, struck the airport perimeter fence.

The pilot sustained a minor bump on the head but was otherwise uninjured. The aircraft’s right wheel was torn off and there was damage to the right side of the tail and the right wingtip. The aircraft’s propeller was also bent.

Safety message

This incident highlights the importance of maintaining directional control when landing, particularly in gusty conditions. A Safety Alert produced by the National Transportation Safety Board in the United States, Stay Centred: Preventing Loss of Control During Landing, addresses this issue and directs pilots to other resources which provide guidance in conducting crosswind approaches and landings.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

What happened

On 11 February 2018, at 1227 Eastern Daylight-saving Time (EDT), the crew of a Robinson R22 Beta helicopter were conducting flight training on the western grass area of Bankstown Airport, New South Wales (NSW). There were an instructor and a student on board. The weather at the time was fine with 15 knots of wind from the south-east gusting to 25 knots.

While practicing hover drills at 2–3 m above the ground, with the student at the controls, the helicopter commenced a yaw and started to spin anti-clockwise. The rate of rotation increased and the instructor took control of the helicopter, but was unable to arrest the spin. The helicopter impacted the ground, the tail boom separated and the skids were flattened. The instructor shut down the helicopter, and both crew members walked to the flight school. Both crew members sustained minor injuries.

Figure 1: Accident scene, indicating direction of rotation at time of impact.

Source: NSW Police Force

Safety message

Instructing ab-initio students in rotary wing flight is a complex task. The instructor must allow the student the experience of controlling the helicopter while moderating the student’s inputs in order to ensure controllability of the aircraft. Flight in gusty conditions increases difficulty for both the instructor and the student.

Wind gusting between 15 and 25 knots places the helicopter in and out of effective translational lift.^[1] Students may have trouble reconciling the effect of their inputs against movement created by the wind. Instructor workload increases as the student’s control inputs are likely to be larger and less predictable than those used in calm conditions.

CASA Australia and CAA New Zealand produced a Helicopter Flight Instructor Manual which describes hovering as requiring a high degree of coordination. It advises that hovering should not be taught until the student is competent in manipulation of flight controls in forward flight, climbing, descending and turning. The manual also advises to ‘keep a close watch on temperatures, pressures and wind velocity during prolonged hovering’.

While conducting flight training instructors should consider meteorological conditions and the limits of the student’s ability to manage them. Safety Notice SN-42 in the Robinson R22 Pilot’s Operating Handbook advises that ‘…pilots should be aware of conditions (a left crosswind, for example) that may require large or rapid pedal inputs’. To assist instructors, flying schools should publish policies to limit flight in unfavourable conditions and accommodate the competence of their students in varying weather conditions.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

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1. Effective Translational Lift (ETL) increases the efficiency of the rotor system and is achieved between 16 and 24 knots of wind. FAA Helicopter Flying Handbook Chapter 2

What happened

On 4 January 2018, at about 0900 Central Daylight-saving Time (CDT), a Robinson R22 helicopter departed from a private property in Katherine, Northern Territory. The pilot, who was the sole occupant, was conducting a private flight to obtain GPS coordinates of structures on a property 38 km south-west of Tindal, NT.

The pilot landed the helicopter alongside a fence line in long grass. The pilot remained in the helicopter, with the engine running and obtained coordinates as required. The pilot then manoeuvred the helicopter into a low hover and with the breeze coming from the north-east, commenced to move out of the hover and felt the helicopter move to translational lift.^[1] The pilot lifted the power to maximum take-off while easing the cyclic^[2] forward to take advantage of the headwind.

As the helicopter straightened, about 3 ft above ground level (AGL), it dipped suddenly, pivoting on the front left-hand skid. The pilot attempted to pull the cyclic back but the helicopter rolled to the left and the main rotor blades contacted the ground at full power, almost severing them at the blade roots. The main rotor blades cut the tail boom into three pieces, lodging the tail rotor and assembly into the ground about 5 m in front of the fuselage. The fuselage came to rest on the left side.

Although hanging from his seatbelt, the pilot was able to shut off the master; however, was unable to reach the fuel shut off valve. The pilot’s seat base dislodged and fell off once the pilot released himself from the seatbelt.

Post-accident observation

The pilot observed two old barbed wires leading from the fence line at a 45-degree angle One wire appeared to have broken with impact and the other wire was entangled around the front left-hand skid.

The wires were half buried in the ground and below the grass top level, making them invisible.

Figure 1: Accident site showing fence wire

Source: Operator

Safety action

As a result of this occurrence, the pilot has advised the ATSB that they are taking the following safety actions:

• avoid landing in grass any higher than skid tube height
• conduct a thorough visual inspection when lifting off around fences.

Safety message

This incident provides a reminder to pilots to conduct a thorough visual inspection to confirm wire locations and other hazards.

This accident highlights the value of restraints and safety helmets for pilots to prevent more serious injury.

ATSB report AO-2014-058 provides an account of a serious head injury to an R22 pilot who was not wearing a helmet. In a later ATSB report, AO-2015-134, the operator commented that the pilot of an R22 accident would have sustained more serious head injuries if he was not wearing a helmet.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

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1. Translational lift occurs when clear, undisturbed air, flows through the rotor system from wind or forward speed.
2. Cyclic: a primary helicopter flight control that is similar to an aircraft control column. Cyclic input tilts the main rotor disc, varying the attitude of the helicopter and hence the lateral direction.