Departure procedures misunderstanding contributes to loss of separation incident.

Key points:

• Boeing 777 turned right on departure from Sydney Airport instead of left, resulting in a loss of separation with an ATR72 that had departed from the parallel runway
• Flight management computer was incorrectly amended so that the aircraft tracked to the east rather than following the cleared standard instrument departure procedure
• Occurrence illustrates the importance of procedural correctness, effective communication and crew coordination

Likely flight crew confusion with Sydney-centric departure procedures contributed to a Boeing 777 turning right instead of left on departure from Sydney Airport, resulting in a loss of separation with an ATR72 which had taken off from the parallel runway, an ATSB investigation notes.

The United Airlines Boeing 777-300ER had departed from Sydney Airport’s runway 34 Left bound for San Francisco and was cleared to follow a standard instrument departure (SID) requiring the aircraft to maintain runway heading until reaching 1,500 feet, at which point the aircraft was required to turn left and track towards Richmond, northwest of Sydney. However, the 777 instead climbed straight ahead through 1,500 feet to about 2,100 feet and then turned to the right, resulting in a loss of separation with the Virgin Australia ATR aircraft, which had departed from the parallel runway (runway 34 Right).

“The Sydney air traffic control departures controller detected that the 777 was turning right and instructed the crew to immediately turn left,” noted ATSB Director Transport Safety Dr Stuart Godley.

“The departures controller then issued a separate instruction to the ATR 72 to turn right. At their closest point of approach, the two aircraft were separated by about one nautical mile laterally and about 200 feet vertically.”

Dr Godley noted that while the ATSB categorised this particular loss of separation as a serious incident, both aircraft were fitted with advanced traffic alert and collision avoidance systems (TCAS), which would have alerted the flight crews of each aircraft of any likely flight path conflicts, had the departures controller not issued interventional instructions.

The ATSB’s investigation found that in entering the cleared ‘RIC5’ standard instrument departure in the 777’s flight management computer (FMC), the aircraft captain, who was the pilot flying, closed (removed) a deliberate ‘discontinuity’ – or gap – in the waypoint sequence. This discontinuity was pre-programmed to represent where air traffic control was to provide radar vectors to transition from the SID to join the planned oceanic track to San Francisco.

In removing the discontinuity, likely due to the captain’s limited exposure to the assignment of varying Sydney-centric departure procedures, the aircraft was in effect programmed to track direct to a navigation waypoint (DIPSO), about 45 nautical miles to the east of Sydney, after reaching the initial waypoint at 1,500 feet. This resulted in the right turn and the subsequent loss of separation with the ATR72.

Removing the discontinuity would have been appropriate for many procedural transitions, which are commonplace in the United States, Dr Godley noted.

“This reprogramming may have been due to an unfamiliarity with radar transitions from a standard instrument departure to an en route track.”

The ATSB’s investigation also notes that the pilot flying probably did not effectively communicate the changes made to the FMC coding to the other members of the flight crew, after reprogramming the FMC from the anticipated simpler ‘SYD1’ standard instrument departure, which had been entered based on previous experience.

“This occurrence illustrates the importance of procedural correctness, effective communication and crew coordination,” said Dr Godley.

“Any amendment to the flight management computer, particularly those applicable to the more critical phases of flight such as departure and arrival procedures, should always be announced, and then carefully and independently verified by at least one other crew member.”

The incident also highlights that, when possible, air traffic controllers can potentially further assist foreign flight crews when providing airways clearances by proactively factoring the crew’s possible unfamiliarity with local procedures.

Read the final report: Loss of separation involving Boeing 777, N2333U and ATR 72, VH-FVQ, near Sydney Airport, New South Wales, on 22 January 2020

Driveshaft failure leads to a hard landing.

Key points:

• Fatigue crack causes driveshaft failure
• Pilot promptly initiated precautionary landing
• Manufacturer recommends driveshaft replacement after 5,000 hours

A UH-1H ‘Huey’ helicopter was substantially damaged during a hard landing while conducting fire control operations in December 2019 following a driveshaft failure caused by a fatigue crack, a new ATSB investigation details.

The pilot of the helicopter, who was using a 1,200 litre fire-fighting bucket on a 150 foot ‘long-line’ to conduct firebombing operations, experienced vibrations and a buzzing noise just prior to uplifting water from the Crawford River, north of Port Stephens, NSW. The pilot aborted the uplift, released the bucket and began positioning the helicopter to conduct a precautionary landing in a cleared area. However, after assessing that the helicopter’s condition was deteriorating, the pilot elected to land in a small clearing, which required an approach to the hover prior to landing.

On approach to the hover, at a height of about 10 feet above the ground, the helicopter started to yaw right. Despite the pilot’s attempt to stop the yaw, directional control could not be regained, which resulted in a hard landing. The main rotor blades then struck the ground, which resulted in the main gearbox, mast, rotors and driveshaft separating from the airframe.

The pilot was able to exit the helicopter, uninjured.

“This accident highlights the importance of pilots operating helicopters in low-level environments immediately responding to the early signs of a problem, and being prepared to commit to a precautionary landing before a situation deteriorates to the point of a forced landing,” said ATSB Director Transport Safety Dr Stuart Godley.

“In this case, the pilot responded without delay and was able to reach a safe landing site before the catastrophic driveshaft failure.”

The ATSB’s investigation determined that the driveshaft, which transmits power from the engine to the main gearbox, failed due to a fatigue fracture of the outer flex plate attached to the main gearbox fitting.

The accident helicopter had been fitted with a ‘KAflex’ driveshaft, manufactured by Kamatics Corporation in the early 1980s as part of a US Army UH-1H driveshaft retrofit program. The KAflex driveshaft uses flexible plates to accommodate relative movement between the engine and gearbox, and was designed with an integral failsafe feature for continued flight in the event of a single flex frame fracture.

The KAflex is used widely on a number of different helicopter types, and those fitted to UH-1Hs under the US Army retrofit program did not have a defined service life (and were considered ‘on condition’).

“The US Federal Aviation Administration is currently reviewing a position paper submitted by the driveshaft manufacturer, which recommended that KAflex driveshafts with the same part number as the accident helicopter should be replaced at 5,000-hours service, or, if the time-in-service could not be determined, removed and replaced,” said Dr Godley.

“Any legacy driveshafts can be sent to the manufacturer for modification to a new ‘safety of flight’ part number.”

Read the final report: Driveshaft failure and hard landing involving Overseas Aircraft Support UH-1H helicopter, VH-OXI, near Crawford River, New South Wales, on 7 December 2019

ATSB releases Broome R44 helicopter accident update.

The Australian Transport Safety Bureau has released an update from its on-going investigation into the fatal accident involving a Robinson R44 helicopter at Broome, Western Australia on 4 July.

“Based on CCTV footage and examination of the wreckage, ATSB investigators have been able to determine that the helicopter’s tail rotor gearbox, tail rotor and tail assembly separated from the helicopter soon after take-off,” said ATSB Chief Commissioner Greg Hood.

Following the in-flight separation of the tail, the helicopter then fell to the ground, out of control.

“We appreciate that this information may be confronting to the families and friends affected by this tragic accident, and it is for this reason that the ATSB will not be releasing the CCTV footage due to its potentially distressing nature,” Mr Hood said.

Since arriving on site in Broome on Monday, transport safety investigators have conducted a detailed inspection of the helicopter wreckage, and are arranging to transport relevant components back to the ATSB’s technical facilities in Canberra for further examination.

Investigators have also interviewed a pilot who flew the accident aircraft on 2 July who reported feeling unusual vibrations through the tail rotor pedals. The pilot of the accident flight also conducted a short flight in the helicopter and confirmed the unusual vibrations.

Maintenance personnel subsequently conducted a dynamic tail rotor balance on the day before the accident.

“At this stage the reasons for the in-flight breakup, and the significance of the reported vibrations through the tail rotor pedals, are not known, and the ATSB will provide further advice when relevant information is available,” Mr Hood said.

“While the investigation is on-going, the ATSB urges any R44 pilot that experiences unusual vibrations through the tail rotor pedals to land as soon as possible.”

As the investigation progresses, the ATSB will continue to liaise with the Civil Aviation Safety Authority, the US National Transportation Safety Board, and the Robinson Helicopter Company.

The Robinson R44 was certified in December 1992 and the model involved in this accident, the R44 Raven I, was introduced in January 2000. There are currently 558 R44s on the Australian civil aircraft register.

Read the update: In-flight break-up, Robinson R44 Raven I, VH-NBY, 3 km north of Broome Airport, Western Australia, on 4 July 2020

Prevent and detect carbon monoxide in aircraft.

The Australian Transport Safety Bureau is advising owners, operators, pilots and maintainers of piston-engine aircraft to take measures to detect the presence of, and prevent the entry of, carbon monoxide in aircraft cabins.

The national transport safety investigator is today issuing two Safety Advisory Notices and releasing an update to its on-going investigation into the collision with water of a DHC-2 Beaver floatplane at Jerusalem Bay, on the Hawkesbury River north of Sydney, on 31 December 2017, in which the pilot and five passengers lost their lives.

“During the draft review process for the investigation’s final report, the aviation medical specialist engaged by the ATSB recommended that carbon monoxide toxicology testing be undertaken on blood samples of the aircraft occupants,” said ATSB Chief Commissioner Greg Hood.

The results of that testing, provided to the ATSB in March 2020, indicated that the pilot and two of the passengers, whose post-mortem examinations established received fatal injuries sustained as a result of the impact sequence, had elevated levels of carbon monoxide.

Accident aircraft’s engine exhaust crack

Note pre-existing crack spread and widened during the impact.  Source: ATSB

Subsequent to receiving those results the ATSB consulted widely with medical experts to fully understand those results.

“From that consultation with medical experts, and research into the effects of carbon monoxide on aircraft operations, the ATSB considers the levels of carbon monoxide were likely to have adversely affected the pilot’s ability to control the aircraft,” Mr Hood said.

The ATSB then re-examined the accident aircraft and undertook testing on an exemplar Beaver aircraft to replicate the potential source of carbon monoxide and ingress into the aircraft cabin.

“Having discounted other potential sources of carbon monoxide exposure, the ATSB considers it likely that the pilot and passengers were exposed to carbon monoxide inside the aircraft cabin,” Mr Hood said.

“The ATSB found pre‑existing cracking of the engine exhaust collector-ring, which could lead to exhaust leakage into the engine bay. Further, the ATSB found a breach in the firewall from missing bolts used to secure magneto access panels in the firewall under the instrument panel in the cabin. Any breach in the firewall can allow the ingress of gases from the engine bay into the cabin.” 

The aircraft had departed from Cottage Point and taxied for about seven minutes before taking off on its planned return trip to Rose Bay. Shortly after take-off, the aircraft deviated from the operator’s standard flight path, stopped climbing, and entered the confines of Jerusalem Bay below the height of surrounding terrain. The aircraft then continued along the bay, made a very steep right turn, and collided with the water.

The confirmation that there were elevated levels of carbon monoxide in the pilot’s blood, and the potential for engine exhaust gases to exit the exhaust system in the engine bay and enter the aircraft’s cabin has prompted the ATSB to issue the two Safety Advisory Notices to industry.

“This investigation is on-going, and our final report, which will contain specific findings, is anticipated to be released in coming months, so we are limited in discussing specific details. However, if at any time during an investigation, should the ATSB identify issues that are critical to safety, we will immediately notify relevant stakeholders so proactive safety action can be taken to help prevent similar occurrences,” said Mr Hood.

Accident aircraft’s engine firewall showing the location of missing bolts

Source: ATSB

“That is why today the ATSB is publishing two Safety Advisory Notices focused on the prevention and detection of carbon monoxide in piston-engine aircraft.”

Although the accident aircraft involved a DHC-2 Beaver, these issues are relevant to piston-engine aircraft in general, Mr Hood noted.

“The ATSB is reminding aircraft maintainers that the primary mechanism for the prevention of carbon monoxide exposure to aircraft occupants is to carry out regular inspections of aircraft exhaust systems to identify and repair holes and cracks, and to detect breaches in the firewall,” he said.

The ATSB is also highlighting the limitations of disposable carbon monoxide chemical spot detectors, as used commonly in general aviation, and was fitted to the accident aircraft.

Spot detectors have a limited shelf-life, can be affected by factors such as direct sunlight and cleaning chemicals, and are passive, relying on pilots to regularly monitor them.

“In contrast, electronic active carbon monoxide detectors are designed to attract the pilot’s attention through auditory and/or visual alerts when carbon monoxide levels are elevated,” Mr Hood said.

“These detectors are now inexpensive and widely available. Had there been an alert of the presence of carbon monoxide, the pilot would have been able to take measures to reduce the risk to those on board.”

Mr Hood noted that the ATSB has kept the Civil Aviation Safety Authority (CASA) informed as to the investigation’s progress. To date, CASA has contacted all operators and owners of the 20 DHC-2 Beaver aircraft registered in Australia to emphasise the importance of inspections of the exhaust system, to confirm that the scheduled inspections were being conducted, and to seek information pertaining to the number of exhaust ring segments requiring repair or replacement.

In addition, CASA has published an Airworthiness Bulletin today to highlight the risks and dangers of carbon monoxide poisoning to all piston-engine owners, operators and aircraft engineers, and advising of the fitment of active carbon monoxide detectors.

Read the investigation update AO-2017-118

Read the Safety Advisory Notices AO-2017-118-SAN-001: Inspection of exhaust systems and engine firewalls

Read the Safety Advisory Notices AO-2017-118-SAN-002: Are you protected from carbon monoxide poisoning?

Flight crew workload contributes to delayed response to high rate of descent.

High workload likely delayed a Boeing 787 flight crew’s response to an abnormally high rate of descent while conducting an instrument landing system (ILS) approach to land at Perth Airport, prompting a ‘glideslope’ alert from the aircraft’s enhanced ground proximity warning system (EGPWS).

During the approach, the Scoot Airlines Boeing 787-9’s autopilot flight director system (AFDS) entered a degraded mode and presented the crew with information that they erroneously believed represented the glideslope. The crew followed the displayed information, which resulted in a descent below the designed approach path and the subsequent activation of the EGPWS ‘glideslope’ alert. The crew conducted a go-around, and completed an uneventful approach and landing.

An ATSB investigation into the incident found that during the approach, a disturbance of the ILS glideslope signal occurred, likely due to an aircraft taxiing for take-off in front of the glide path antenna, resulting in the 787 capturing the ILS glideslope prematurely. Because of this, the AFDS entered a degraded mode, presenting the crew with information extrapolated from a previous position, rather than updated glideslope information.

While taking actions to reset the AFDS, the crew continued descending as per the presented information, without identifying cues that indicated the information was unreliable.

The report notes the flight crew were likely experiencing higher than normal workload, due to a combination of the high speed approach and troubleshooting the unexpected glideslope indications.

This reduced the effectiveness of cockpit communication and delayed correction of the aircraft’s low altitude. This resulted in the abnormally high rate of descent, leading to descent below the designed approach path, and activation of the EGPWS glideslope alert.

The ATSB reminds flight crews that when conducting an ILS approach in visual conditions, ILS signal paths are not protected by air traffic control, and may be subject to interference. Constantly monitor the aircraft’s flight path to ensure that guidance presented to the flight crew is valid. This will also ensure that early action can be taken to correct any deviation from the approach path.

Read the final report: Operational event involving Boeing 787, 9V-OJC, near Perth Airport, Western Australia, on 4 December 2015

Maitland light aircraft accident preliminary report released.

The Australian Transport Safety Bureau has released the preliminary report from its ongoing investigation involving an amateur-built Osprey 2 amphibious light aircraft near Maitland Airport on 17 May.

The preliminary report, which details basic factual information established in the investigation’s early evidence collection phase, confirms that the aircraft had departed Maitland Airport with the pilot as the sole occupant to conduct a test flight. This was to be the amateur-built* aircraft’s third flight, operating under a special certificate of airworthiness – experimental, which required that 25 hours of flight-testing be conducted.

“The planned flight involved climbing to 3,000 feet to conduct flight-testing over the airfield,” said ATSB Director Transport Safety Stuart Macleod. “However, about three minutes after taking off to the south-west from Maitland’s runway 23, witnesses on the ground at the airfield observed white smoke coming from the aircraft.”

After being contacted on the radio, the pilot noted the engine was running rough and informed of the intention to return for a landing on runway 23 (from the north-east).

The engine subsequently failed completely and the pilot reported changing to runway 08, to land from the west.

“While on approach to runway 08, the aircraft was then observed to roll to the left, descend and impact the ground,” Mr Macleod said.

The pilot sustained fatal injuries and the aircraft was destroyed.

Mr Macleod noted ATSB preliminary reports do not contain findings, identify contributing factors or outline safety issues and actions, which are detailed in an investigation’s final report.

“The investigation is continuing and will include examination of the aircraft’s engine, maintenance documentation and operational records along with build documentation. Investigators will also examine recovered instruments and electronic devices, the aircraft's performance characteristics and recorded flight data, and the pilot’s qualifications and experience,” Mr Macleod said.

“During the course of the investigation, should safety critical information be discovered at any time, the ATSB will immediately notify stakeholders so that appropriate and timely safety action can be taken.”

* The Civil Aviation Safety Authority defines an amateur-built aircraft as an aircraft, the major portion of which has been fabricated and assembled by a person or persons who undertook the construction project solely for their own education or recreation.

Read the preliminary report: Collision with terrain involving amateur-built Osprey 2 amphibian aircraft, VH-WID, near Maitland Airport, New South Wales, on 17 May 2020

Floatplane accident highlights go-around considerations.

A Cessna Caravan floatplane operating a scenic charter flight over the Great Barrier Reef clipped trees and impacted dense scrubland while attempting to go-around after an aborted water landing, a new ATSB investigation report details.

The aircraft, with a pilot and 10 passengers on board, was attempting a landing at Whitsunday Island’s Chance Bay on 28 January 2016 when it bounced three times on the water’s surface, after the pilot reported holding off the landing in order to fly through an observed wind gust. After the second bounce, with the aircraft nearing the beach, the pilot increased engine power and initiated a go-around. A more pronounced third bounce, which occurred almost immediately after the second, resulted in the aircraft rebounding about 30 to 50 feet above the water.

While increasing power, the pilot perceived that the engine torque was indicating red, suggesting an engine over-torque for the selected propeller configuration. Noticing that the climb performance was less than expected with the flaps at the 30-degree setting, the pilot stopped increasing power and reduced the flap to 20 degrees.

As it climbed straight ahead towards a saddle, the aircraft’s climb performance was still below the pilot’s expectations. Assessing that the aircraft would not clear the surrounding rising terrain, the pilot turned right. However, during the turn the aircraft clipped trees before coming to rest in dense scrub about 150 metres from the eastern end of the main beach, near the top of a ridge.

Variable water conditions and the possibility of sharing the landing area with marine vessels means that every water landing has the potential to be markedly different.

The pilot promptly advised the passengers to exit and move away from the aircraft. Some of the passengers suffered minor injuries in the accident, but all were able to leave the aircraft quickly. There was no post-impact fire, but the aircraft was substantially damaged.

The ATSB’s investigation found that the aircraft’s initial contacts with the water were past the pilot’s nominated decision point and beyond the northern boundary of the water landing area. This, combined with the delay in initiating the go-around, reduced the options and margins available for a safe outcome.

“Variable water conditions and the possibility of sharing the landing area with marine vessels means that every water landing has the potential to be markedly different,” ATSB Director Transport Safety Stuart Macleod said.

“In this case, despite the perceptions of over-torque, the pilot initiated a go-around without using all available power and the optimal speed, turned towards higher terrain, and placed the aircraft in a down-wind situation, which ultimately resulted in the collision with terrain.”

Mr Macleod said a go-around is standard practice and is typically a safe option whenever landing conditions are not satisfactory.

“However, it is important that pilots consider aircraft performance and local conditions when planning an exit route, including conducting mental rehearsals of standard procedures.”

The investigation also found that the engine operating limitations detailed in the float manufacturer’s pilot operating handbook supplement were not consistent with other guidance and may have influenced the power level applied by the pilot during the go-around.

The investigation also noted that the aircraft was equipped with lap-sash seatbelts, which have been demonstrated to reduce injury, while the use of emergency beacons and satellite phone facilitated a timely response to the accident.

Read the final report: Collision with terrain involving Cessna 208 Caravan, VH-WTY, 11 km north-east of Hamilton Island Airport, Queensland on 28 January 2016

Beach runway overrun highlights need for pilots to be prepared to go around.

A GA8 Airvan’s nosewheel collapsed when the aircraft struck a washout after it overran a beach runway. The accident occurred after the pilot elected not to conduct a go-around despite several cues to do so, an ATSB investigation found. 

The Air Fraser Island Airvan was returning to land on a beach on Fraser Island after conducting a scenic flight with a pilot and seven passengers on board on 2 January 2020. During the landing approach, the pilot observed a vehicle on the beach close to the 500 metre long runway, which the operator’s ground crew had marked out with traffic cones, and elected to land about a third of the way down the runway.

Shortly after touching down, the aircraft became airborne again, with the pilot reporting pulling back on the control column to raise the nose to minimise passenger discomfort as the aircraft passed over holes in the sand.

After passing the holes, the aircraft touched down again and the pilot attempted to brake. However, the aircraft was still at speed as it approached the end of the marked runway, beyond which was an ankle-deep freshwater soak, or washout. As the aircraft overran the runway, the pilot reported raising the nose to lift the aircraft over the washout, concerned that the aircraft would flip if the nose wheel struck the water.

Immediately beyond the washout, the aircraft pitched forwards onto its nose landing gear, which collapsed. The propeller then struck the sand and the aircraft came to a halt.

While the aircraft was substantially damaged, the pilot and passengers were uninjured.

After the accident, the operator’s safety manager paced out the distance from where the aircraft landed after passing the holes, and reported that approximately 100 metres of runway remained. A video of the landing taken by a passenger from inside the aircraft showed that less than 5 seconds elapsed between the landing and when the aircraft stopped.

“The ATSB investigation into the accident found the pilot did not conduct a go-around despite several cues to do so, such as sighting the vehicle near the runway and when becoming airborne again after the first touchdown,” ATSB Director Transport Safety Dr Stuart Godley said.

“The aircraft subsequently landed with insufficient runway remaining to prevent a runway overrun, and the overrun was onto a section of beach unsuitable for a landing roll due to a washout.”

The investigation noted that Fraser Island beaches pose a very dynamic environment for aircraft operations, with potential hazards including vehicles, people, animals and changing tides and sand conditions.

“This accident highlights to pilots the importance of being prepared to go around – to be ‘go-around minded’ – especially when, as was the case in this instance, the full available runway length is required for a safe landing and no obstacle-free overrun area exists,” Dr Godley said.

Read the final report: Runway overrun involving Gippsland Aeronautics GA8, VH-BNX, Cornwell’s ALA, Fraser Island, Queensland, on 2 January 2020

ATSB releases Lockhart River Cessna collision with terrain preliminary report.

The ATSB has released a preliminary report from its ongoing investigation into the collision with terrain of a twin-engined Cessna 404 Titan aircraft near Lockhart River, Queensland on 11 March, in which the pilot and four passengers on board lost their lives.

The preliminary report details factual information established in the investigation’s early evidence collection phase, including the accident’s sequence of events derived from the aircraft’s track and altitude, information determined from examining the wreckage and impact site, and weather details.

The Cessna had departed Cairns at 7:19am for a planned same-day return charter flight to Lockhart River, the report notes. The forecast weather for their arrival at Lockhart River was for overlapping periods of rain and low cloud with possible thunderstorms.

ATSB Executive Director Transport Safety Nat Nagy said investigators were able to build an understanding of the aircraft’s flightpath using transmitted GPS data recorded at five-second intervals by an electronic flight bag application on the pilot’s iPad.

That data showed that the pilot was conducting an area navigation (RNAV) GPS instrument approach using track and distance data from satellite navigation receivers to try and land at Lockhart River. For vertical navigation the pilot was using a combination of altimeter and GPS distance information.  

Tragically, the descent continued until the aircraft impacted a sand dune on the coast, fatally injuring all on board.

“When the aircraft was about 30 km from Lockhart River, the pilot joined the approach and followed the procedure down to the missed approach waypoint. The pilot continued to track to the runway and operated below the minimum descent altitude (MDA) for a short period until the pilot initiated a missed approach,” Mr Nagy said.   

The aircraft climbed to 3,500 feet and tracked for a second GPS approach. 

“When flying a GPS approach, the minimum safe altitude progressively steps down between waypoints as the aircraft gets closer to the runway,” Mr Nagy explained.

Halfway along the approach, the aircraft descended through the minimum safe altitude of 1,800 feet for that segment. About 30 seconds after the final approach fix, the data shows the aircraft nearing 700 feet with an apparent decrease in the descent rate for a short period. The aircraft then descended below the minimum descent altitude and diverged to the left, crossing the inbound track at an angle of about 20°.

“Tragically, the descent continued until the aircraft impacted a sand dune on the coast, fatally injuring all on board,” Mr Nagy said.  

The accident site was located on a sand bank adjacent to the beach, about 6 kilometres south-east of Lockhart River Aerodrome and 300 metres to the south-west of the specified RNAV approach track, Mr Nagy explained.

“Examination of the wreckage indicated that both engines were operating normally with substantial power on impact and that the landing gear was extended. There was no evidence of any structural or mechanical defects with the aircraft.”

Mr Nagy noted that ATSB preliminary reports do not contain findings, identify contributing factors or outline safety issues and actions, which will be detailed in the investigation’s final report.

“As the investigation continues, the ATSB will continue its analysis of recorded flight data and weather conditions,” he said.

“We will also examine the operation of the aircraft’s Garmin GNS 430W avionics units; the training and checking processes for RNAV approaches, including missed and subsequent approaches; and look at existing and potential risk controls for controlled flight into terrain, noting that the aircraft was not fitted with, nor was it required to be, an enhanced ground proximity warning system.”

Mr Nagy also noted that the aircraft was not fitted with a cockpit voice recorder or a flight data recorder, but nor was it required to be.

Read the preliminary report: Controlled flight into terrain involving Cessna 404, VH-OZO, Lockhart River, Queensland, on 11 March 2020

ATSB releases aerial firefighting occurrences safety analysis.

The ATSB has published a statistical report of aerial firefighting accident and incident occurrence data spanning a near 20-year period, in response to a request for information from the Royal Commission into National Disaster Arrangements.  

The safety analysis forms a central element of the ATSB’s response to the Royal Commission, commonly referred to as the Bushfire Royal Commission, which requested information on “key operational and safety challenges encountered in coordinating and responding to fires associated with the use of aircraft and aerial firefighting techniques”.

ATSB Director Transport Safety Dr Stuart Godley noted the report details both the number of occurrences and, where data was available, the rate of occurrences per hours flown and number of flights, for aircraft conducting aerial firefighting operations, including water-bombing, surveillance and air attack tasks, for the period 1 July 2000 to 31 March 2020.

The ATSB could only draw upon limited exposure data to determine the rates of occurrences.

“Aviation activity relating to aerial firefighting has increased over recent bushfire seasons. Estimates for the most recent season, 2019 to 2020, have been that there was a four-fold increase in aerial firefighting activity compared to other recent bushfire seasons.” Dr Godley noted.

“More occurrences involving aerial firefighting aircraft were reported to the ATSB this financial year (between July 2019 and March 2020) than in any prior financial year in the study period. Further, there were two fatal aerial firefighting accidents between August 2018 and March 2020, whereas in the previous 17 years there were only three fatal accidents,” Dr Godley noted.

“However, given the amount of recent bushfire activity in Australia, an increase in reported occurrences could be expected, so this does not indicate an increase in risk per flight.

Since 2018 the ATSB has commenced six investigations involving aerial firefighting aircraft, including into the Lockheed C‑130 large air tanker collision with terrain near Cooma, New South Wales, on 23 January 2020, in which three flight crew were fatally injured. This number represents about one third of all investigations involving aircraft conducting aerial work commenced by the ATSB since 2018.

Dr Godley stressed that while the number of occurrences does give some indication of overall risk, the ATSB could only draw upon limited exposure data to determine the rates of occurrences, either on a per hours flown or numbers of flights basis.

“The ATSB was only able to draw upon Bureau of Infrastructure Transport and Regional Economics (BITRE) exposure data for Australian-registered aircraft conducting aerial firefighting from 2014 to 2018, while data was not available for hours and flights flown by foreign-registered aircraft operating in Australia.”

Foreign-registered aircraft accounted for about 16 per cent of reported aerial firefighting occurrences in Australia, the report notes. Foreign-registered aircraft were also significantly larger in comparison to Australian-registered aircraft, with an average maximum take-off weight around 10 times higher.

The statistical review also sought to identify any risks associated with aerial firefighting in addition to those inherent with low‑level flying by comparing the occurrence rates for Australian-registered aerial firefighting aircraft to the combined occurrence rates for other aircraft undertaking low-level aerial work flying in Australia between 2014 and 2018.

“Generally, the rates for incidents, serious incidents and accidents are relatively low for aerial firefighting compared to other aerial work activities,” Dr Godley noted.

“Further, it is highly likely that the rate of reported terrain collisions was lower for Australian‑registered aerial firefighting aircraft than other low‑level flying aerial work activities,” Dr Godley said.

The review did find that it is highly likely that the rate of reported occurrences involving Australian‑registered aerial firefighting aircraft, compared to other low‑level flying aerial work, was greater for communications‑related occurrences; encounters with remotely piloted aircraft; airframe‑related technical issues; flight preparation/navigation operational occurrences; aircraft separation occurrences; and operational non‑compliance occurrences.  

Read the research report AR-2020-022: A safety analysis of aerial firefighting occurrences in Australia, July 2000 to March 2020