[Peetwo]

Popinjay to the rescue: Broome R44 in flight breakup FR released? 

Mr Attribution still ATCB Media rep for this week? Via PJ HQ: 

ATSB releases Broome R44 helicopter accident investigation final report



Key points

• An overstress fracture, shortly after take-off, led to the separation of the tail rotor gearbox from the helicopter, and the subsequent separation of the aft tail section;
  
• Pilots had previously reported experiencing vibrations in the helicopter’s tail rotor pedals;
  
• Investigation highlights that aircraft should not be returned to service until known issues are rectified, and that a conservative approach to troubleshooting mechanical issues and return to service should be taken to minimise risk
  

An ATSB investigation into a fatal helicopter accident that occurred shortly after take-off from a yard in a Broome industrial suburb highlights the crucial importance of pilots formally declaring their helicopters to be unserviceable when the source of unusual vibrations has not been identified and rectified.

On 4 July 2020, a Robinson R44 helicopter with a pilot and three passengers on board conducted a vertical departure from an industrial property at Bilingurr, 3 km north of Broome Airport, to conduct a private joyflight. As the helicopter climbed clear of obstacles and transitioned to forward flight, witnesses on the ground heard a loud bang, and observed the helicopter’s empennage and tail rotor system separate and break away.

The helicopter continued to climb and commenced rotating to the right with increasing angular velocity, before control was lost, and it impacted a road on its right side. The pilot and the passenger, who were seated on the right side of the helicopter were fatally injured. The two passengers who were seated on the left side of the helicopter sustained serious injuries.

“The ATSB found that an overstress fracture of the tail rotor gearbox’s input cartridge occurred following a period of vibration in the helicopter’s tail rotor pedals,” said ATSB Chief Commissioner Angus Mitchell.

“This overstress fracture, shortly after take-off, led to the separation of the tail rotor gearbox from the helicopter, and the subsequent separation of the aft tail section.”

The ATSB’s investigation report notes the helicopter’s two previous flights were conducted by two separate pilots (including the accident pilot, who was also the helicopter’s owner), who both reported experiencing vibration in the helicopter’s tail rotor pedals.

In response the owner requested that their local approved maintenance organisation assess the vibration. Engineers from the maintenance organisation assessed the helicopter in the yard on the afternoon of 3 July. They found the tail rotor balance to be within limits, and a close inspection of the tail cone, tail rotor and empennage of the helicopter detected no issues. Further, no vibration in the pedals was detected during ground running of the helicopter in the yard.

Nonetheless, the maintenance engineer reported wanting a pilot to fly the helicopter to determine if the reported vibration in the pedals was detectable in flight.

However, while the requirement for a maintenance check flight was not recorded on the helicopter’s maintenance release, the owner of the maintenance organisation advised the ATSB that they advised both the owner and the pilot who first detected the vibrations of the requirement to fly the helicopter to provide more information. Friends and family of the owner of the helicopter stated that no request for further flight was made.

“As the vibration was reported to only occur in flight, and no defect was identified, it was reasonable to have concluded that the problem may still be present,” said Mr Mitchell.

“As such, the safest next step, which is recommended by the helicopter manufacturer, would be to conduct a graduated flight check of hovering then re-inspection. Preferably, this would be with only a prepared pilot on board.

“Instead, the next flight, during which the accident occurred, involved the conduct of a high‑power towering take-off from a confined area with 3 passengers on board.”

The investigation report notes that the registered operator of an aircraft has ultimate responsibility for its airworthiness.

“This accident demonstrates the importance of following a conservative troubleshooting process that minimises risk.”

Mr Mitchell noted that while the source of the loading that led to the overstress fracture was not conclusively determined, the pilot’s operating handbook for the R44 helicopter states that the onset of unusual vibrations can indicate impending failure of a critical component.

“The pilot’s handbook states that pilots should land as soon as possible and formally declare the helicopter unserviceable.

“Crucially, the helicopter should not be returned to service until the source of the vibration, both on the ground and airborne, has been found and rectified.”

Mr Michell also noted that private pilots do not, unlike commercial and airline pilots, have the benefit of regular flying and frequent training and checking.

“The ATSB recommends private pilots to not rely on the minimum training and checking and training currency requirements to keep safe, and that they assess their risk profile and seek opportunities to maintain and develop their skills with a flight instructor.”

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

Publication Date
12/04/2023

Still not sure why you would have Popinjay being the front man for the media blurb? Shirley it would be much more appropriate for one of the conga line of Directors of Transport Safety; or even (God Forbid) the IIC?? Better still why not just rely on the primacy of the final report, after all PJ is just reading from the 'safety message'?? 

Safety message

The pilot’s operating handbook for this helicopter stated that the onset of unusual vibrations can indicate impending failure of a critical component. Pilots should land as soon as possible and formally declare the helicopter unserviceable. Crucially, the helicopter should not be returned to service until the source of the vibration, both on the ground and airborne, has been found and rectified.

The registered operator of an aircraft has ultimate responsibility for its airworthiness. This accident demonstrates the importance of following a conservative troubleshooting process that minimises risk. The tools to manage airworthiness are freely published by the Civil Aviation Safety Authority and include the correct use of an aircraft’s maintenance release to clearly communicate the state of the aircraft and any required maintenance action.

Finally, private pilots do not have the benefit of regular flying and frequent training and checking afforded to commercial pilots. Therefore it is recommended that private pilots do not rely on minimum training and checking and currency to keep them safe. Instead they are encouraged to assess their risk profile and seek opportunities to maintain and develop their skills with a flight instructor.

P2 comments: To begin this investigation to complete took 2 years, 9 months and 8 days. Although being 1 month past compliance with ICAO Annex 13 Para 7.3, there was a preliminary report published. Plus 6 days after the accident there was an update, which read very much like a interim/prelim report and was issued (I believe) because the investigation had already identified significant safety issues:  

Update: 10 July 2020

Wreckage information

Based on closed-circuit television (CCTV) footage and an examination of the wreckage, the ATSB investigation into the fatal R44 helicopter accident near Broome Airport on 4 July 2020 has determined that the helicopter experienced an in-flight breakup. The tail rotor gearbox assembly, tail rotor and empennage assembly separated soon after the helicopter lifted off. The fuselage then fell to the ground out of control.

The ATSB has conducted a detailed examination of the entire aircraft at Broome, and is transporting relevant components back to Canberra for more detailed examination. These components include the tail rotor gearbox, tail rotor, empennage, tail cone, tail rotor drive shaft, and flight controls. During this process, the ATSB has been consulting with the Robinson Helicopter Company (the helicopter manufacturer), the US National Transportation Safety Board and the Australian Civil Aviation Safety Authority.

Images of the components that separated are provided at the end of this update. The ATSB will not be releasing the CCTV footage due to its potentially distressing nature. The ATSB is providing access to the footage to relevant experts to assist with the investigation.

Additional information

The ATSB has interviewed a pilot who recently flew the helicopter and maintenance personnel who conducted maintenance on the helicopter. It has also obtained copies of the helicopter’s maintenance records and reviewed other documentation. Based on this information:

• The R44 Raven I helicopter involved in the accident (serial number 2544) was manufactured in 2018. It was imported new into Australia and was first registered on the Australian civil aircraft register in August 2018.
  
• The helicopter underwent its last periodic (100 hourly) inspection on 4 June 2020, with 286.9 hours total time in service.
  
• A pilot who flew the helicopter on 2 July 2020 to Broome Airport reported feeling unusual vibrations through the tail rotor pedals. He described it as if something was repetitively tapping through the pedals. The pilot of the accident flight also conducted a short flight in the helicopter and confirmed the unusual vibrations.
  
• Maintenance personnel conducted a dynamic tail rotor balance on 3 July 2020 (the day before the accident). The dynamic tail rotor balance was found to be within limits, and the maintenance personnel could not detect any unusual vibration on the ground.
  
• The accident flight was the first flight since the maintenance was conducted. Overall, the helicopter had 291 recorded hours in service.
  
• The Robinson R44 was certified in December 1992 and the R44 Raven I was introduced in January 2000. There are currently 558 R44s on the Australian civil aircraft register.
  

Further investigation

In the initial phase of its investigation, the ATSB is focussed on examining the wreckage, reviewing the CCTV footage and reviewing potentially related occurrences.

At this stage the reasons for the in-flight breakup are not known. The ATSB will provide further advice when relevant information is available.

Pilot advisory information

The R44 Pilot’s Operating Handbook (POH) includes the following 'safety tip':

A change in the sound or vibration of the helicopter may indicate an impending failure of a critical component. If unusual sound or vibration begins in flight, make a safe landing and have the aircraft thoroughly inspected before flight is resumed. Hover helicopter close to the ground to verify problem is resolved, and then have aircraft reinspected before resuming free flight.

The ATSB strongly endorses this advice, and urges any R44 pilot that experiences unusual vibrations through the tail rotor pedals to land as soon as possible and follow the advice in the POH safety tip.

 
So that's a Gold tick, IE the ATSB is actually doing their legislated job -    

After that the investigation timeline indicates that the ATSB also issued an interim report (as per ICAO Annex 13) only 5 weeks past the anniversary date of the accident.

MTF...P2