Damage to nose and left main landing gear demonstrates importance of visual inspections

Key points:

• Visual inspection detected damage to nose landing gear light and main landing gear
• Nose gear landing light was probably struck and damaged during departure from Sydney
• No debris was found during runway inspections
• No visible biological evidence of a wildlife strike 

Damage found to the nose landing gear light and left main landing gear of an Airbus A320 discovered by the flight crew after a flight from Sydney to Proserpine demonstrates the importance of visual inspections, a new ATSB investigation notes.

The Jetstar Airways A320 had operated a scheduled service from Sydney to Proserpine on 5 March 2020 when on their post-flight walkaround the flight crew found the damaged landing light and left main landing gear, including a pierced hydraulic brake line.

“The ATSB’s investigation determined that the nose gear landing light was probably struck and damaged during departure from Sydney, and that the glass lens from the light most likely struck the main landing gear, piercing a hydraulic brake line,” said ATSB Director Transport Safety Stuart Macleod.

Hydraulic fluid found in the main gear wheel well, likely from the punctured hydraulic line, was probably discharged when the crew raised the landing gear during departure from Sydney, while the investigation also notes that there was no indication that the aircraft had been struck by ground support equipment prior to departure from Sydney.

“While the cause of the damage could not be determined, the nose gear landing light was probably struck and damaged during departure from Sydney.”

Mr Macleod said the investigation considered if the aircraft struck foreign object debris during its take-off roll, or a bird or a drone during departure from Sydney before the landing gear had been retracted.

“However, no debris was found during runway inspections at Sydney Airport, there was no evidence of a drone operating in the area, and there was no visible biological evidence of a wildlife strike.”

As a result, the source of the impact to the nose gear landing light could not be conclusively determined.

“This incident highlights the important role visual inspections play in maintaining the safety of an aircraft,” said Mr Macleod.

“In this case, a vigilant flight crew identified damage to their aircraft that could have otherwise impacted on the safety of subsequent flights.”

Read the final report: Landing gear damage involving Airbus A320, VH-VFL, near Sydney, New South Wales, on 5 March 2020

The ATSB is considering several factors that could have contributed to a R44’s main rotor blade striking its fuselage

The ATSB is considering a number of factors that could have contributed to a Robinson R44’s main rotor blade striking the helicopter’s fuselage in flight as part of its ongoing investigation into a 2 December 2020 collision with terrain accident east of Goulburn.

Wreckage examination indicated that the main rotor struck the helicopter’s fuselage in flight. The uncontrollable aircraft subsequently collided with terrain, fatally injuring the trainee pilot and instructor on board, an ATSB preliminary report details.

“As we move forward with the investigation, we will consider a number of factors that could have contributed to a rotor blade impacting the fuselage in flight, such as turbulence, pilot input, engine issues and aircraft controllability,” said ATSB Director Transport Safety, Stuart Macleod.

The training flight had departed Goulburn Airport shortly before 4 pm, with the helicopter’s last recorded automatic dependent surveillance broadcast (ADS-B) detecting it descending into a valley in the Morton National Park at 4.11 pm. An aerial search was launched when the helicopter failed to return to Goulburn as expected, with the wreckage located in a valley approximately 4 km north-west of the last ADS-B transmission.

The report notes that the accident helicopter had been manufactured in May 2020 and at the time of the accident had an estimated 150 hours total time in service. During a periodic maintenance inspection in November 2020, and in line with a safety alert from the manufacturer, the engine’s intake valves were inspected and reinstalled with new gaskets.

“To date the ATSB has attended the accident site twice for examination and evidence collection, examined the helicopter’s engine and tail rotor driveshaft and interviewed relevant parties,” said Mr Macleod.

“As well as analysing weather conditions at the time of the accident, the ATSB will continue our detailed technical examination of the engine and other recovered components, including electronic devices.”

The preliminary report notes that the two closest automatic weather stations to the accident site showed significantly different weather from one another—both 1 hour prior to, and at the time of the accident. At Goulburn, 31 km to the west, recorded conditions were winds from a north-westerly direction, up to 9 kt, visibility greater than 10 km, and the temperature was 25°C. There was no other significant weather observed, while at Moss Vale, 43 km to the north-east, a special weather report was first issued at 1538, due to a significant deterioration of weather conditions in the area. These conditions continued for several hours, with a layer of broken cloud descending to 1,100 ft above sea level, with a second layer of overcast cloud descending to 1,600 ft.

Mr Macleod explained that the preliminary report does not include any safety findings or analysis, which will be detailed in the investigation’s final report.

“However, should a critical safety issue be identified during the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken,” he said.

Read the preliminary report: In-flight break-up involving Robinson R44 Raven I, VH-HGU, 31 km east of Goulburn Airport, New South Wales, on 2 December 2020

An unfortunate outcome for an operator who, in addressing one problem, inadvertently created another. 

The hard landing of a Robinson R22 helicopter on a private property near Derby, Western Australia last year was an unfortunate outcome for the operator who, in addressing one problem, inadvertently created another hazard that resulted in substantial damage to the helicopter.

An occurrence brief* published by the Australian Transport Safety Bureau (ATSB) into the 23 December 2020 accident details how the pilot of an R22 was preparing to take off from a helicopter landing site covered with rubber matting made from conveyor belts as a means of limiting an in-flight visibility condition known as ‘brownout’. Brownout can obscure nearby visual references necessary for a pilot to control a helicopter when near to the ground, which can cause spatial disorientation and loss of situational awareness leading to an accident.

As the helicopter became airborne, it moved backwards slightly due to a headwind, resulting in the heel of the skid sliding between two overlapping sheets of matting. As the pilot attempted to gain height, the skid did not free itself and the helicopter pitched back and rolled to the left.

The pilot recognised the early onset of dynamic rollover and attempted to recover by lowering the collective. While that action prevented a rollover, it resulted in a hard landing and substantial damage to the helicopter. The pilot was not injured.

As a result of this incident, the helicopter operator has taken a number of positive safety actions including the removal of rubber conveyor belt matting from all company helicopter landing sites. The operator also issued an internal safety alert to its pilots reminding them of the requirements to ensure company helicopter landing sites are clear of any objects that could cause dynamic rollover on take-off, and how dynamic rollover can occur and the appropriate recovery technique.

*Occurrence briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries by the ATSB. Because occurrence briefs are not investigations under the Transport Safety Investigation Act 2003, the information within them is de-identified, and provides an opportunity to share safety education messaging in the absence of an investigation.

CO exposure likely significantly degraded ability of Beaver floatplane pilot to safely operate aircraft 

Carbon monoxide exposure likely significantly degraded the ability of the pilot of a Beaver floatplane to safely operate the aircraft before it collided with water in Jerusalem Bay on the Hawkesbury north of Sydney in December 2017, fatally injuring all six people on board, the final report from Australian Transport Safety Bureau investigation into the accident has found.

As advised with the ATSB’s publication of two safety advisory notices arising from the investigation in July 2020, several pre-existing cracks in the aircraft engine’s exhaust collector ring very likely released exhaust gas into the engine/accessory bay, which then very likely entered the cabin through holes in the main firewall where three bolts were missing. The pilot also undertook a 27-minute taxi - to free the dock for another arriving and departing aircraft - before the passengers were boarded which likely exacerbated the pilot’s elevated carboxyhaemoglobin level.

“Shortly after take-off for the return flight from Cottage Bay to Sydney Harbour’s Rose Bay, the aircraft conducted a 270 degree right turn in Cowan Water and then entered Jerusalem Bay, below the height of the surrounding terrain,” said ATSB Chief Commissioner Greg Hood.

“It stopped climbing, continued along the bay and then made a very steep right turn. The aircraft’s nose then dropped and the aircraft collided with the water.”

From detailed analysis of photos recovered from the camera of one of the passengers on board the aircraft, as well as witness accounts, the ATSB was able to establish the accident sequence of events, and found that some of the circumstances of the flight were unexpected, given the nature of the flight and the pilot’s significant level of experience.

“The aircraft entered a known confined area, Jerusalem Bay, below the height of the surrounding terrain, when there was no operational need to enter the bay,” Mr Hood noted.

“Further, the aircraft did not continue to climb despite being in the climb configuration, and a steep turn was performed at low‑level and at a bank angle in excess of what was required.

“The aircraft likely aerodynamically stalled, with insufficient height to recover before colliding with the water.”

Toxicology results identified that the pilot and passengers had higher than normal levels of carboxyhaemoglobin in their blood. This was almost certainly due to elevated levels of carbon monoxide in the aircraft cabin.

“The pilot would have almost certainly experienced effects such as confusion, visual disturbance and disorientation,” said Mr Hood.

“Consequently, the investigation found that it was likely that this significantly degraded the pilot's ability to safely operate the aircraft.”

Mr Hood noted that at the time of releasing an interim report into the accident in December 2018, investigators were considering the possibility of pilot incapacitation due to the series of unexpected, and up to that point, unexplained events during the flight.

The ATSB engaged an aviation medical specialist, who, working with other medical specialists closely examined all aspects of the pilot’s medical history including electrocardiogram traces and medical reports, with no pre-existing medical conditions evident.

The ATSB was of the understanding that testing for carbon monoxide exposure on the aircraft’s occupants was conducted as part of initial toxicology examinations. However, in late 2019, the ATSB’s aviation medical specialist recommended that this be confirmed, Mr Hood noted.

“Subsequent toxicological testing indicated that the pilot and all passengers had elevated levels of carboxyhaemoglobin.”

Mr Hood thanked the families and colleagues of those lost in the accident for their understanding and support while the ATSB progressed this comprehensive investigation, culminating in the public release today of the 144-page final report.

“This investigation report release will bring the families of those lost in this tragic accident a greater sense of understanding of the circumstances of the loss of their loved ones.”

Mr Hood said the investigation would have been considerably aided if the aircraft had been fitted with an on-board recording device. The accident Beaver aircraft’s maximum take-off weight was less than 5,700 kilograms and so was below the regulatory threshold requiring the fitment of a flight recording device (such as a cockpit voice recorder and/or a flight data recorder).

“Recording devices have long been recognised as an invaluable tool for investigators in identifying the factors behind an accident, and their contribution to aviation safety is irrefutable,” said Mr Hood.

Historically, due to cost considerations and technological limitations, the fitment of recording devices has only been mandated for larger aircraft.

“However, advancements in technology have made self-contained image, audio and flight data recording systems far more cost-effective and accessible to all aircraft.

“That is why we are today formally recommending that the International Civil Aviation Organization and the Civil Aviation Safety Authority consider mandating the fitment of lightweight recording devices to smaller passenger-carrying aircraft.

“There are a large number of commercial passenger-carrying operations conducted in aircraft that do not require the fitment of flight recorders. So there remains the potential for unresolved investigations into accidents involving smaller passenger carrying aircraft, which poses a significant limitation to bringing about safety improvements in this sector of aviation.”

Mr Hood said the circumstances of the Jerusalem Bay accident highlight the insidious danger CO exposure poses to aircraft occupants.

“This investigation reinforces the importance of conducting a thorough inspection of piston-engine exhaust systems and the timely repair or replacement of deteriorated components,” he said.

“In combination with maintaining the integrity of the firewall, this decreases the possibility of CO entering the cabin.”

Further, the investigation also highlights that the use of an attention attracting CO detector provides pilots with the best opportunity to detect CO exposure before it adversely affects their ability to control the aircraft or become incapacitated.

“The ATSB strongly encourages operators and owners of piston-engine aircraft to install a CO detector with an active warning to alert pilots to the presence of elevated levels of CO in the cabin. Where one is not fitted, pilots are encouraged to carry a personal CO detector.”

The ATSB has recommended that the Civil Aviation Safety Authority consider mandating the carriage of active warning CO detectors in piston-engine aircraft, particularly passenger carrying aircraft.

Read the final report: Collision with water involving a de Havilland Canada DHC-2 Beaver aircraft, VH‑NOO, at Jerusalem Bay, Hawkesbury River, New South Wales, on 31 December 2017

Overgrown helipad contributes to tail rotor strike and collision with terrain.

While manoeuvring close to the ground in a confined and overgrown landing site on Moa Island in the Torres Strait, the pilot of a LongRanger helicopter experienced difficulty locating the helipad before the helicopter’s tail rotor contacted trees, resulting in the helicopter spinning rapidly and colliding with terrain.

On the morning of 22 April 2020, the Bell 206L1 LongRanger operated by Nautilus Aviation was conducting a passenger charter flight from Moa Island’s Kubin Airport to Banks Peak with a pilot and two passengers on board.

Shortly after 8.00am, the pilot manoeuvred over the top of the helipad and used the helicopter’s rotor downwash to push away overgrown grass to reveal the edges of the helipad. During this process, the tail rotor contacted several tree branches of up to 45 mm in thickness located on the eastern side of the helipad.

A video taken by one of the passengers recorded that as the helicopter was turning to the right, a buzzing sound was heard followed by a crack. Immediately after this sound, the helicopter spun rapidly to the right before rolling left and colliding with terrain.

The video also showed that during the accident sequence, the left rear door opened. As a result of the spinning and rolling, the rear left passenger’s legs were forced out of the door and became trapped under the helicopter, resulting in serious injuries. The right rear passenger sustained a serious injury to one hand.

During the accident, the pilot’s helmet impacted the aircraft’s structure, resulting in a brief loss of consciousness. Paint transfer on the pilot’s helmet was of a colour matching the interior paint of the cabin. The investigation found that the use of a helmet very likely reduced the severity of the pilot’s injuries.

“The wearing of helmets is an important safety consideration when performing utility aerial work,” Director Transport Safety Dr Mike Walker said.

“Survivability in the event of an accident, as was highlighted in this case, is greatly increased by wearing a helmet.”

The investigation also highlights the importance of the design and ongoing maintenance of helicopter landing sites and helipads in tropical environments, and that maintenance schedules must account for rapid plant growth.

“Helicopter landing site owners are encouraged to add touchdown and positioning markings to their facilities,” Dr Walker said.

“Additionally, if a landing cannot be conducted as planned, pilots should reject the landing and go-around to re-evaluate their options from a safe position away from obstacles.”

Safety action taken by Nautilus Aviation since this accident has seen its HLS template amended to include a grading system for site assessment by the chief pilot or deputy chief pilot prior to tasking pilots. Nautilus has also developed a risk assessment template for landing at non-surveyed sites, in addition to sending an alert to its pilots reinforcing the go-around procedure as stated in its operations manual.

The lessee of the helicopter landing site, the Department of Home Affairs, has also conducted a formal risk assessment of Banks Peak and other higher-risk sites throughout the Torres Strait. The Department has ceased flying operations to landing sites deemed to have unacceptable risks until sufficient control measures have been implemented. In addition, the Department is developing a detailed HLS brief for aircraft operators and is considering the most appropriate mechanisms for systematic engagement with other users of its landing sites.

Read the final report: Collision with terrain involving a Bell 206L-1, VH-NBR, at Banks Peak, Moa Island, Queensland, on 22 April 2020

Train replacement coach driver surprised level crossing was activated for freight services in the area. 

Key points

• Coach stopped foul of tracks on level crossing after crossing protection warnings began operating.
• Coach stopped despite having adequate time to clear the crossing.
• The train was unable to stop and impacted the front-left corner of the coach

A passenger coach was struck by a freight train after it stopped foul of a Geelong level crossing when the coach driver stopped on the crossing after boom gate warning lights activated, despite having adequate time to clear the crossing, a new transport safety investigation notes.

The coach, with a driver and single passenger on-board, was operating a rail-replacement service from Melbourne to Waurn Ponds in Geelong on the morning of 2 April 2020 and had just entered the Station Street level crossing when the crossing warning system activated in response to an approaching freight train. The driver of the coach immediately applied the brakes and the coach stopped within the crossing, foul of the first track.

When the crew of the freight train observed the coach, the locomotive driver made an emergency brake application while the co-driver began to sound the horn. The coach driver heard the train horn and attempted, unsuccessfully, to reverse the coach off the crossing.

The train was unable to stop and impacted the front-left corner of the coach. The coach driver and passenger were injured in the collision and were taken to hospital. The coach driver was released from hospital the same day, and the passenger the next day.

The subsequent investigation into the incident, conducted on behalf of the ATSB by Victoria’s Chief Investigator Transport Safety, confirmed that the coach had stopped past the boom barrier with the front-left corner of the coach foul of the track.

The acute road-to-rail track angle and the position of the left-front corner of the bus relative to the track may have influenced the driver’s perception of the crossing, the investigation notes.

“Had the driver not stopped the coach when the crossing warning system activated, there was adequate time to complete the crossing prior to the arrival of the freight train,” said Chief Investigator Chris McKeown.

At interview with transport safety investigators, the driver indicated that he did not continue over the crossing as he did not want to be reported for crossing with the bells ringing.

Further, the driver indicated that he was surprised when the crossing was activated, as they were under the impression that V/Line trains were not running because they were driving a train replacement service.

When the coach driver was alerted to the train’s presence by the train horn, the driver recalled attempting to reverse the coach, but reported that they had forgotten to release the park brake.

“Motorists need to be aware that in situations where passenger train services are not operating, freight trains may be operating, and normal safety precautions should be observed,” stated Mr McKeown.

Although probably not directly related to this incident, in the previous six years, there had been 20 occurrences of the boom barrier strikes by road vehicles on the inside lane of the Station Street approach. This suggests that the crossing configuration is probably conducive to driver error on that approach, and that additional risk controls may be warranted, Mr McKeown noted.

“While there were no identified queueing issues at the crossing that may have triggered a requirement to applying yellow box markings, such markings may have assisted the driver’s identification of the crossing limits and the hazardous zone.”

Read the final report: Level crossing collision between freight train 5KQ7 and a road coach, at Norlane, Victoria, on 2 April 2020

An update on the investigation into the collision with terrain at Carcoar, NSW.

The ATSB will analyse data from the pilots’ personal electronic devices and evaluate witness information as part of its on-going investigation into the fatal accident of an Aquila training aircraft south of Orange, Central West New South Wales, on 4 November 2020.

An instructor and a student pilot undergoing a check flight prior to undertaking a commercial pilot licence flight test were on-board the aircraft when it collided with the ground shortly after departing a private airstrip at the Coombing Park property, near Carcoar, south of Orange.

The investigation update notes that the aircraft impacted the bank of a small dam, located on rising terrain about 600 metres beyond the end of the runway and about 30° to the left of the runway centreline.

“To date, the ATSB has examined the aircraft wreckage, interviewed witnesses, and retrieved personal electronic devices and aircraft components from the accident site,” said ATSB Acting Director Transport Safety Kerri Hughes.

“On-site examination of the aircraft’s flight controls, engine and structure did not identify any pre‑existing faults or failures,” she said.

“In addition, evidence of fuel spillage at the accident site indicated that the aircraft had fuel onboard, while the presence of fuel in the fuel filters indicated the engine had fuel supply at the time of the accident.” 

The investigation update also notes that the recorded weather at nearby Orange Airport at the time of the accident included visibility of greater than 10 km with no cloud detected, and an 11 knot wind from the west.

Ms Hughes noted the progress update does not include any safety findings or analysis, which will be detailed in the investigation’s final report.

“As well as analysis of electronic data from the pilot’s personal electronic devices and considering witness information, the ATSB will also examine a number of recovered aircraft components and analyse the aircraft’s maintenance history, weight and balance, and performance,” she said.

“The ATSB will also examine flight planning for the accident flight; the operator’s policies and procedures; and review pilot qualifications, experience and medical information.”

A final report will be released at the conclusion of the investigation.

“However, should a critical safety issue be identified during the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken,” Ms Hughes noted.

Read the investigation progress update.

Overcharged light rail vehicle battery.

Key points:

• Battery overcharging generated excessive hydrogen that ignited and ruptured the battery system enclosure
• Software controlling the battery charging voltage was ineffective due to undetected data corruption
• Numerous ‘battery over temperature faults’ were recorded in the train monitoring system but drivers were not alerted

A light rail vehicle’s roof-top mounted battery system ruptured and ejected the enclosure cover off the vehicle’s roof when excessive hydrogen generated from battery overcharging ignited, a new ATSB report says.

The Sydney Light Rail vehicles (LRV) 053/054 were stabled at the light rail depot in Randwick overnight on 2–3 April 2020. At about 2:49 am workers in the yard heard a loud noise and found a roof-mounted battery enclosure cover on the ground behind two other light rail vehicles.

A review of closed-circuit TV footage showed a flash coming from the battery enclosure as the cover was ejected from the roof of LRV 053. The cover struck the overhead contact wire and was airborne for about 5 seconds before striking the two nearby LRVs and falling between them.

“Undetected data corruption of the battery system’s auxiliary converter configuration software, likely present from its initial upload and throughout validation testing, resulted in the batteries overcharging and high battery cell temperatures going undetected,” said Mick Quinn, Acting Chief Investigator, Office of Transport Safety Investigations (OTSI).

In New South Wales, OTSI conducts rail and light rail investigations on behalf of the ATSB under the Transport Safety Investigation Act 2003

“The auxiliary converter configuration software changes the battery charger voltage in response to battery cell temperature; as the battery cell temperature increases the charger voltage should decrease,” Mr Quinn said.

Overcharging then depleted the electrolyte levels of the battery cells and generated excessive hydrogen within the batteries.

“As flammable gases, including the hydrogen, released into the battery enclosure and encountered an undetermined ignition source they ignited and the force of expanding gases ruptured the enclosure ejecting the cover from the roof of the vehicle.”

“The ejected cover weighed 20 kg and was airborne for approximately 4.12 seconds in which time it struck the overhead contact wire likely slowing the ascent,” Mr Quinn explained.

“The cover landed approximately 6 m away from LRV 053 and posed a significant hazard to anyone in the area. Further, chemical hazards could also have caused burns or eye damage if released when the enclosure ruptured.”

The investigation notes that while a ‘battery over temperature fault’ was recorded in the train monitoring system when battery temperatures reached 60 °C for more than 5 seconds, and the fault warning was retained for review in the maintenance list in the driver’s display unit, no alert was generated for the driver.  

A review of the maintenance list found the battery had recorded frequent over temperature faults in the 30 days leading up to the occurrence.  

“The introduction and commissioning of new assets like light rail vehicles must ensure that design requirements and risk controls are tested and validated as functional and that fault monitoring and maintenance regimes monitor asset condition to avoid circumstances that might escalate and contribute to accidents,” said Mr Quinn.

As a result of the occurrence, the train monitoring system was updated so that it alerts light rail drivers to battery over temperature faults, while additional software validation and testing is planned by the battery charger software supplier and vehicle manufacturer during software acceptance testing and after the upload of revised software.

Read the final report: Uncontained battery failure involving Sydney Light Rail Vehicle 053, Randwick LRV Depot, New South Wales, on 3 April 2020

Safety Advisory Notice warns of cracking in Yak-52 aluminium elevator bellcranks.

The ATSB has released a Safety Advisory Notice to Yakovlev Yak-52 aircraft owners and maintainers highlighting the potential for fatigue cracking in Yak-52 aluminium alloy elevator bellcranks.

The Safety Advisory Notice comes as a result of the ATSB’s ongoing investigation into the collision with water of a Yak-52 aircraft during a private aerobatic flight near South Stradbroke Island, Queensland, on 5 June 2019, in which the pilot and passenger were fatally injured.

“During the course of the investigation, the ATSB detected two small cracks in the aircraft’s aluminium elevator bellcrank, one of which was established to be a pre-existing fatigue crack,” said Acting ATSB Director Transport Safety, Kerri Hughes.

“The ATSB stresses that the crack did not contribute to the South Stradbroke Island accident. However, cracking in this area can result in the failure of the bellcrank and a subsequent loss of control of the aircraft,” said Ms Hughes.

A review of the available Yak-52 maintenance documentation identified a difference in the requirements for inspecting the bellcrank, Ms Hughes noted.

In 2009, Yakovlev amended the aircraft’s scheduled maintenance program to require a dye penetrant inspection of the elevator bellcrank every 25 flying hours (plus or minus 5 hours). In 2012, as a result of a fatal Yak-52 accident in 2010, where the elevator bellcrank had failed in-flight, Yakovlev directed that all aluminium bellcranks be replaced with steel.

However, the Yak-52 is an ex-military ‘warbird’ aircraft that was not designed to western civil certification standards and is flown in Australia under a Limited category special certificate of airworthiness.* Consequently, neither the 2009 requirement to use dye penetrant inspections every 25 flying hours, nor the 2012 requirement to replace aluminium bellcranks with steel bellcranks, had been incorporated into maintenance schedules for the aircraft in Australia, and nor was there a requirement to do so.

In Australia, Yak-52 elevator bellcranks were required to be dye penetrant inspected every 100 flying hours or 12 months.

“Given the known fatigue cracking and potential failure of Yak‑52 elevator bellcranks manufactured from aluminium alloy, the ATSB reminds maintainers and operators of the importance of dye penetrant inspections to detect and remove defective bellcranks from service,” Ms Hughes said.

“The ATSB would also like to ensure that operators and maintainers of Yak‑52 aircraft are aware that Russia, the aircraft’s state of design, increased the inspection frequency for the bellcranks to 25 plus or minus 5 flying hours. Further, aluminium alloy bellcranks are no longer approved for use on Yak-52s operating in Russia.”

The ATSB’s investigation into the South Stradbroke Island accident is continuing, with a final reported anticipated to be released in the first half of 2021. Pending the publication of an investigation’s final report, the ATSB may issue Safety Advisory Notices to raise awareness of safety critical concerns determined during the course of an investigation without waiting for the conclusion of the investigation.

Read the Safety Advisory Notice AO-2019-027-SAN-024: Elevator bellcrank inspections

* Under the Civil Aviation Safety Authority’s Limited category(Opens in a new tab/window), operators can fly warbird ex-military and replica aircraft in Australia on an ‘informed participation’ basis where they are willing to accept the risk of the aircraft not meeting international airworthiness certification standards.

Aviation Occurrence Statistics report update.

The ATSB has released an update to the Aviation Occurrence Statistics report with the inclusion of 2019 aviation activity data (hours flown and aircraft departures) not available at time of initial publication.

ATSB Director Transport Safety, Dr Stuart Godley said the earlier report published in April contained 10 years of occurrence data from 2010 to 2019, but that aviation activity data (used to calculate rates) was only available from 2014–2018.

“The addition of last year’s aviation activity data allows for accident rates to be presented for the period 2014–2019,” said Dr Godley.

“Accident rates (accidents per hour flow or departure) is an important measure for the level of risk associated with different aviation activities and allows for a comparison between activities.”

The updated statistics shows that aviation activity involving test and ferry flights, aircraft registered with Recreational Aviation Australia (RAAus), followed by pleasure and personal transport, had the highest accident rates over 2014–2019.

For aircraft types of aircraft, recreational aeroplanes followed by commercial balloons are shown to have the highest accident rates, with recreational aeroplanes also having the highest fatal accident rate. 

Dr Godley explained that in order to provide more timely information to industry, the Aviation Occurrence Statistics report will now be published bi-annually, with the data published earlier in the year to include occurrence data (number of occurrences) for the previous year followed by an update later in the year including updated activity data.

“Both occurrence data and rate data are important tools for assessing the safety risk of aviation activity by providing two reports the ATSB aims to present safety information in a timely and relevant manner to industry,” he said.

The updated edition also incorporates interactive web versions of all tables and graphs to allow the user to display aviation occurrence data in the format of their choice.

Read the report AR-2020-047: Aviation Occurrence Statistics (rates update) 2010 to 2019