COVID-19 business support loans open

Source: State of Tasmania Government

30 March 2020

Michael Ferguson, Minister for State Growth

I am pleased to announce that our new Business Support Loan Scheme, provided through the Government’s social and economic stimulus package, is now open for applications through the Business Tasmania website.

Given the significant impact the unfolding COVID-19 situation is having on Tasmanian businesses, interest free loans of between $20,000 and $250,000 have been made available to assist eligible local businesses through this difficult time*.

Loans are available for business continuity purposes, such as:

  • The purchase of business plant and equipment;
  • Improving distribution channels and online shopping accessibility;
  • Implementing initiatives to improve the sustainability and viability of the business; and
  • Ensuring essential business continuity is maintained.

Generally, loans will be considered for eligible businesses in Tasmania that operate in the hospitality, tourism and seafood export sectors, as well as related supply chain businesses and those that can demonstrate they have been significantly impacted by the outbreak.

Loans will be available to businesses with a turnover of $10 million or less as per the applicant’s most recent financial statements, however businesses with turnover in excess of $10 million per year that operate in multiple locations will be considered by exception.

We will continue to work closely with local businesses so they are ready to continue trading and return to full strength once we overcome the immediate COVID-19 threat.

This new loans scheme will be complemented by the Federal Government’s stimulus and support packages, which will be of particular value in helping businesses maintain links with their staff and want to prepare for the future beyond COVID-19.

For more information or assistance with your application call Business Tasmania on 1800 440 026 or email ask@business.tas.gov.au

Applications are available on the Business Tasmania website: https://www.business.tas.gov.au/covid-19_business_support_packages

* Loans will be interest free for the first three years then payable at State Growth’s commercial loan interest rate from year four onwards.

Closure of Wineries in South Australia – New COVID-19 Direction

Source: South Australia Police

An update has been made which affects the operation of wineries and their associated cellar doors and restaurants.

To reduce the spread of COVID-19 within South Australia the State Coordinator has made a direction under the Emergency Management Act 2004 to restrict wineries with cellar doors and restaurants attached to them.

The direction stipulates that all wineries, cellar doors and restaurants located at wineries in South Australia are to close. The sale of food to the public is to stop.

Wineries that sell food commercially to supermarkets and retail stores are still permitted to produce and sell products, but food products must be transported to retail outlets by commercial freight or the winery itself.

Further, wineries can continue to sell alcohol via online or phone purchases, again provided that they are delivered by commercial freight or the winery themselves.

Wineries are major tourist attractions and as a holiday period approaches, travel to wine regions is discouraged in order to protect these areas from a potential influx of tourists and spread of COVID-19.

Members of the public can find a copy of the Direction in full here.

If you require further information you can call the SA COVID-19 Information Line on 1800 253 787 between the hours of 8.00am to 8.00pm 7 days per week or go to the SA Health website at https://www.sahealth.sa.gov.au or https://www.sa.gov.au/covid-19

Marine Rotational Force – Darwin deployment paused due to COVID-19

Source: Australian Government – Minister of Defence

 After careful deliberation, the Government has decided not to proceed with the 2020 Marine Rotational Force – Darwin (MRF-D) deployment at this time, given ongoing restrictions associated with COVID-19.

Australia will work with the United States to devise options for a possible later deployment, subject to conditions improving and the viability of such a deployment proceeding.

Any decision in relation to the 2020 MRF-D in no way affects Australia’s commitment to host next year’s, or subsequent, MRF-D rotations.

$130 billion JobKeeper payment to keep Australians in a job

Source: Prime Minister of Australia

The Morrison Government will provide a historic wage subsidy to around 6 million workers who will receive a flat payment of $1,500 per fortnight through their employer, before tax.

The $130 billion JobKeeper payment will help keep Australians in jobs as tackle the significant economic impact from the coronavirus.

The payment will be open to eligible businesses that receive a significant financial hit caused by the coronavirus.

The payment will provide the equivalent of around 70 per cent of the national median wage.

For workers in the accommodation, hospitality and retail sectors it will equate to a full median replacement wage.

The payment will ensure eligible employers and employees stay connected while some businesses move into hibernation.

Prime Minister Scott Morrison said the JobKeeper payment would bring the Government’s total economic support for the economy to $320 billion or 16.4 per cent of GDP.

“We will give millions of eligible businesses and their workers a lifeline to not only get through this crisis, but bounce back together on the other side,” the Prime Minister said.

“This is about keeping the connection between the employer and the employee and keeping people in their jobs even though the business they work for may go into hibernation and close down for six months.

“When the economy comes back, these businesses will be able to start again and their workforce will be ready to go because they will remain attached to the business through our JobKeeper payment.”

Treasurer Josh Frydenberg said the country was about to go through one of the toughest times in its history.

“Businesses will close and people will lose their jobs. That is why we have doubled the welfare safety net,” the Treasurer said.

“However, today we are going even further. Australians know that their government has their back.

“That is why we are delivering an historic $130 billion JobKeeper payment to support businesses and to help Australians in a job.

“This will keep Australian workers connected with their employer and provide hope and more certainty during these difficult and challenging times.”

JobKeeper Payment

The JobKeeper Payment is a subsidy to businesses, which will keep more Australians in jobs through the course of the coronavirus outbreak.

The payment will be paid to employers, for up to six months, for each eligible employee that was on their books on 1 March 2020 and is retained or continues to be engaged by that employer.

Where a business has stood down employees since 1 March, the payment will help them maintain connection with their employees.

Employers will receive a payment of $1,500 per fortnight per eligible employee. Every eligible employee must receive at least $1,500 per fortnight from this business, before tax.

The program will commence today, 30 March 2020, with the first payments to be received by eligible businesses in the first week of May as monthly arrears from the Australian Taxation Office. Eligible businesses can begin distributing the JobKeeper payment immediately and will be reimbursed from the first week of May.

The Government will provide updates on further business cashflow support in coming days.

Eligible employers will be those with annual turnover of less than $1 billion who self-assess that have a reduction in revenue of 30 per cent or more, since 1 March 2020 over a minimum one-month period.

Employers with an annual turnover of $1 billion or more would be required to demonstrate a reduction in revenue of 50 per cent or more to be eligible. Businesses subject to the Major Bank Levy will not be eligible.

Eligible employers include businesses structured through companies, partnerships, trusts and sole traders. Not for profit entities, including charities, will also be eligible.

Full time and part time employees, including stood down employees, would be eligible to receive the JobKeeper Payment.  Where a casual employee has been with their employer for at least the previous 12 months they will also be eligible for the Payment.  An employee will only be eligible to receive this payment from one employer.

Eligible employees include Australian residents, New Zealand citizens in Australia who hold a subclass 444 special category visa, and migrants who are eligible for JobSeeker Payment or Youth Allowance (Other).

Self-employed individuals are also eligible to receive the JobKeeper Payment.

Eligible businesses can apply for the payment online and are able to register their interest via ato.gov.au

Income support partner pay income test

Over the next six months the Government is temporarily expanding access to income support payments and establishing a Coronavirus Supplement of $550 per fortnight.

JobSeeker Payment is subject to a partner income test, and today the Government is temporarily relaxing the partner income test to ensure that an eligible person can receive the JobSeeker Payment, and associated Coronavirus Supplement, providing their partner earns less than $3,068 per fortnight, around $79,762 per annum.

The personal income test for individuals on JobSeeker Payment will still apply.

Every arm of government and industry is working to keep Australians in jobs and businesses in business, and to build a bridge to recovery on the other side.

The Government will continue to do what it takes to ensure that Australia bounces back stronger.

Over 1300 checks conducted for COVID restriction compliance

Source: Tasmania Police

Over 1300 checks conducted for COVID restriction compliance – Tasmania Police

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Over 1300 checks conducted for COVID restriction compliance

Monday, 30 March 2020 – 5:16 pm.

Police have conducted over 1300 checks on people in quarantine across the State since 6pm on Wednesday 25 March to 3pm today. Police are being supported by personnel from Tasmania Fire Service, State Emergency Service and the Australian Defence Force and these checks are ongoing.

A group of 10 people will be proceeded against for entering a restricted area at an East Coast camp ground yesterday. A number of non compliance cases also remain under active investigation.

Police also conducted a number of checks of businesses and in public places across the State, including malls, shopping centres and beaches.

There have been very high levels of compliance and understanding of the requirements, but we continue to get reports of people flouting the requirements in some public places and it must be clear that this is not acceptable.

Those required to isolate must fully adhere to the requirement and be aware that if they blatantly disregard these directions that police will initiate formal proceedings.

Those entering Tasmania since 21 March have been given instructions at their arrival points on what they are required to do and they must adhere to that direction.

Under the Emergency Management Act, there is a penalty of up to 100 penalty units ($16,800) or imprisonment not exceeding 3 months for failing to comply with a lawful requirement or direction of an emergency management worker.

Keep your distance

Source: State of Victoria Local Government 2

Monday 30 March 2020

The best way we can all help slow the spread of coronavirus (COVID-19) is to stay home and keep our distance from others, at least 1.5m at all times.

You should only leave your home if you:

  • Are shopping for essentials, like food and groceries
  • Need medical assistance
  • Need to travel to and from work 
  • Are exercising outdoors

Indoor and outdoor meetings are now limited to no more than 2 people. The only exceptions are:

  • People living in the same household
  • Attending a funeral (maximum of 10 people)
  • Attending a wedding (maximum of five people)

Our public outdoor spaces have now closed, including outdoor gyms, parks, playgrounds and golf course.

The Department of Health have some helpful tips on how you can best practise social distancing at home, work and school

COVID-19 update: Advertising claims and hand sanitisers

Source: Australian Therapeutic Goods Administration

Information for consumers

This update is about the kind of advertising claims that can be made in relation to hand sanitisers and COVID-19.

If you are concerned about advertising claims for a hand sanitiser product, you can provide information to us through our online advertising complaint form.

We remind consumers to follow the Department of Health’s good hygiene protocols on slowing down the spread of COVID-19. The Department of Health recommends using soap and water wherever possible. More information about hand sanitisers provided by the TGA is available on the Hand sanitisers and COVID-19 web page.

Information for advertisers

New Excluded Goods Determination for specified hand sanitisers

On 27 March 2020 a delegate of the Minister for Health made a Therapeutic Goods (Excluded Goods—Hand Sanitisers) Determination 2020 (the Determination) excluding specified hand sanitisers from the operation of the therapeutic goods legislation, when advertised or presented for supply in a specified way.

Complying with the therapeutic goods advertising requirements

The advertising framework under therapeutic goods legislation, including the Therapeutic Goods Advertising Code, does not apply to your advertisement for a hand sanitiser product if:

  1. your product is a hand sanitiser that is specified in the Determination; and
  2. any advertisement for that product is consistent with the requirements in the Determination.

Claims relating to COVID-19

Irrespective of whether your product is covered under the new Excluded Goods Determination, you cannot make a therapeutic use claim that directly or indirectly refers to coronavirus (COVID-19).

Hand sanitiser product not specified in the Determination

If your hand sanitiser product is not specified in the Determination, you must comply with the therapeutic goods legislation (including the Therapeutic Goods Advertising Code), and you must be careful not to make any COVID-19 specific advertising claims unless you have permission from the TGA to do so.

We encourage you to refer consumers to the Department of Health’s information on good hygiene protocols available on the departmental website.

Missing teen William Remer

Source: State of Victoria Police

Monday, 30 March 2020 05:12

Police are appealing for public assistance to help locate missing 18-year-old William Remer.

William was last seen at his home address in Toorak about 8.20am this morning.

Police and family are concerned for William’s welfare as he has autism and likes to frequent train stations and bridges.

Police have released an image of William in the hope someone may recognise him and provide information on his current whereabouts.

William is 175cm tall with black hair and was wearing a beige hooded jumper with dark blue tracksuit pants and no shoes.

Anyone who sees William is urged to contact Prahran Police Station on 9520 5200.

Senior Constable Melissa Seach

Media Officer

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Fortitude Valley PCYC demolition works to create new jobs

Source: Government of Queensland

Demolition works are commencing at Fortitude Valley Police-Citizens Youth Clubs (PCYC) to create more Queensland jobs.

Minister for State Development Cameron Dick said construction of the new PCYC is set to begin mid-year, and these works will ensure that start date is hit.

“These demolition works will mean more work for Queenslanders, which is so important right now,” Mr Dick said.

“Silverstone Developments have started removing the indoor basketball court, with works to take about a month to complete.

“The sooner we’re breaking ground, the faster we’re pushing ahead towards construction of a revitalised PCYC for Fortitude Valley.

“It’s anticipated the project will run into early next year, which is great news for the industry and the Queenslanders it employs.”

The PCYC site also has approval for a 12-storey commercial tower.

Member for McConnel Grace Grace said the development was an opportunity to attract more people to the PCYC.

“This redevelopment will breathe new life into the Fortitude Valley PCYC, which is an important establishment in the community,” Ms Grace said.

“I have no doubt the redevelopment will see an increase in locals using the facilities.

“Although PCYC activities are restricted right now, by getting on with demolition and redevelopment works we’re ensuring project delivery remains on track for our community.”

Silverstone Developments Managing Director Troy Daffy said the redevelopment of the PCYC was a real win-win for all parties. 

“At completion of the development, the PCYC will have a state-of-the-art facility, while the remaining parcel of development land will create hundreds of jobs through its future development,” Mr Daffy said. 

“It’s a credit to the state for looking at alternative solutions to create income and generate new jobs for the community.”

ENDS

Media contact: Ben Doyle 0400 775 561

Main landing gear wheel failure during taxi involving Boeing 737, VH-VUH, at Brisbane Airport, Queensland, on 4 January 2017

Source: Australian Transport Safety Bureau

What happened

On 4 January 2017, a Boeing 737-8FE, registered VH-VUH (VUH) and operated by Virgin Australia Airlines Pty Ltd (Virgin) was holding on B3 taxiway at Brisbane Airport, Queensland, when the crew heard a loud noise from what they thought was a burst tyre on the left main landing gear wheel. The crew attempted to return the aircraft to the gate, but were held short of the gate when an attending engineer observed that the number one main wheel assembly (left hand outboard wheel) had failed.

What the ATSB found

The ATSB found that the number one main wheel ruptured due to tie bolt assemblies that had loosened while in service. This allowed the two wheel halves to move relative to each other, resulting in a fatigue crack and eventual wheel rupture. The loosening was most likely due to the presence of anti-seize compound between the wheel halves, which affected the clamping forces.

The ATSB also found that while tie bolt assemblies on this wheel-type (single-web) were more prone to in-service loosening than dual-web wheels, there were no mandated inspections suitable for detecting such loosening. There were also no mandated risk controls to prevent loosening or subsequent rupture.

What’s been done as a result

Virgin advised that following this occurrence, regular inspections were implemented to identify and prevent the loosening of tie bolt assemblies.

The wheel manufacturer updated the wheel’s component maintenance manual with more detailed instructions for applying anti-seize compound.

Boeing has advised the 737 NG fleet of the issue and suggested two possible courses of action. These were based on two optional service bulletins that the manufacturer had in place prior to the occurrence:

  • incorporation of a new inner half-wheel that allows for safe deflation if tie bolt assemblies loosen (Service Bulletin C20626-32-014)
  • the addition of lockwire to the tie bolt nuts, to prevent loosening in the first place (Service Bulletin C20626-32-016).

Safety Message

This incident highlights the importance of compliance with all aspects of manufacturers’ maintenance procedures, including the appropriate application of anti‑seize. This is especially important if, as in this case, there is no simple means of detecting the effect that such excess product can have on fastener security.

What happened

On 4 January 2017, a Boeing 737-8FE, registered VH-VUH (VUH) and operated by Virgin Australia Pty Ltd (Virgin), was scheduled to fly from Brisbane, Queensland to Melbourne, Victoria. Prior to take off, at approximately 1710 Eastern Standard Time,[1] VUH was holding on B3 taxiway when one of the main wheels experienced what was believed to be a burst tyre. The flight crew began to taxi the aircraft back to the gate. An attending engineer instructed the flight crew to stop the aircraft before reaching the gate, as they noticed the number one main wheel assembly (left‑hand outboard wheel) had failed (Figure 1).

Figure 1: Damage to the number one main wheel assembly on VUH

Source: Virgin Australia

The flight was cancelled and passengers disembarked, however, the aircraft could not be jacked and towed via the axle due to the damaged wheel. Instead, wing jacks were sourced and a double wheel change performed on the tarmac. The aircraft was then towed to a maintenance facility for examination.

An inspection at the maintenance facility found that the inner half of the wheel assembly had fractured (see the section titled Wheel design). The tie bolt assemblies that connected the two halves of the wheel were all present with mating faces intact, however some of the bolts were found to be loose.

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Wheel design

This particular wheel-type was designed for use on Boeing 737 NG aircraft. At the time of publication, the wheel manufacturer, Safran Landing Systems, estimated that approximately 2,000 aircraft were using the wheel globally. The wheel assembly used an asymmetric single-web[2] design, with both axle bearings contained within the outer half-wheel (Figure 2). Eighteen tie bolt assemblies connected wheel halves together, with the inner half-wheel attached to the axle only via the tie bolts and outer half-wheel. This asymmetric design allowed for larger brake assemblies to fit within the wheel, unlike dual-web designs where each half-wheel contains an axle bearing.

As a result of the asymmetry, the tie bolts were exposed to a more cyclic load profile (compared with a more symmetrical design). The forces in the bolt could potentially oscillate with the rotation of the wheel while in service.

In this incident, the failed wheel was one of the outboard wheels on the aircraft and a hubcap normally covered the tie bolt assemblies.

Figure 2: Cross section of the main wheel showing the fracture initiation point

Source: Manufacturer, modified by the ATSB

The fracture location was coincident with a region of high stress during service. As seen in Figure 2, the cross section of the inner half-wheel reduced in thickness from left to right. The fracture occurred at the point where its cross section was thinnest, and near a change in geometry (tie bolt hole).

ATSB examination

The wheel halves from the ruptured assembly were initially sent to the ATSB for examination, where the following was found:

  • Twelve of the 18 tie bolt assemblies could be twisted by hand.
  • Several of the nuts had noticeably backed off the thread, with only three of the remaining six nuts above the minimum torque of 163 Nm.
  • The breakaway torque[3] of each nut was tested, and four of the 18 nuts were below the acceptable value of 3.61 Nm.
  • The tie bolt assemblies were visually inspected and found to be the correct part in every instance, with no evidence of damage.
  • A region of the fracture surface near one of the tie bolt holes exhibited fatigue crack progression (beach) marks radiating away from several initiation points (Figures 3 and 4). The remainder of the fracture was consistent with shear overstress. There was no visual indication of material defect at the fatigue crack initiation sites.

Figure 3: Outboard fracture surface on the inner half-wheel, with a fatigue region

Source: ATSB

Figure 4: Fracture morphology of one of the fatigue cracks through the fractured inner half-wheel

Source: ATSB

Manufacturer’s examination

The wheel manufacturer conducted a further examination of the failed main wheel, including a detailed analysis of the fracture morphology. They concluded that the wheel failed as a result of the observed fatigue cracks propagating into a mixed fatigue/ductile rupture mode. A small crack was also detected within the adjacent tie bolt hole, although this did not appear to have contributed to the wheel failure.

The manufacturer verified that the material composition and dimensions of the wheel were within specifications. Their report did not speculate on possible causes or factors contributing to the initiation or propagation of the observed fatigue cracking. However, they subsequently indicated that there was excessive ‘interposition product (anti-seize compound in this case) at the mating face of the occurrence wheel halves and that:

The presence of interposition product could lead to loss of bolt tension and then wheel rupture.

Specifically, it was believed that this interposition product prevented the wheel halves from abutting squarely against each other during assembly. Relative movement of the halves during service then resulted in loosening of the tie bolt assemblies and ultimately failure of the wheel. The manufacturer advised that the same mechanism was believed to have caused wheel failure in this type of wheel in two other instances (see the section titled Previous occurrences).

In March 2018, the wheel manufacturer visited the two different maintenance facilities responsible for Virgin’s 737 NG fleet to examine how the wheels were being maintained. Both facilities were following the tightening technique recommended by the manufacturer. However, at one facility the manufacturer reported seeing silicone grease on the mating faces of some of the wheel halves. This facility did not perform any maintenance on the occurrence wheel, and a subsequent visit by the manufacturer in September 2019 found that the grease was being applied appropriately.

Wheel history and maintenance

The occurrence wheel had undergone three tyre changes since its initial assembly in January 2016. It had operated for 173 cycles (47 days) since its last tyre change. According to one of the maintenance facilities responsible for the work, tie bolt assemblies generally lasted about three to four tyre changes before the lock nuts failed their breakaway torque tests and needed to be replaced. A tyre generally lasted approximately 40 days in service before needing replacement.

When reassembling the wheel after a tyre change, the tie bolt assemblies were tightened using a two-stage process, starting with an automatic dual spindle wrench. This device automatically torqued diametrically opposing nuts to a pre-set value of 70 Nm. In the second stage, the maintenance facility would use a single electronic torque/angle wrench for the final tightening. This involved rotating the nuts 100 degrees, as prescribed in the component maintenance manual (CMM). The wrench then indicated with a coloured light whether each nut was in the acceptable torque range.

This second stage was a relatively new tightening method introduced in 2014 via an optional service bulletin (SB C20626-32-007), to ‘improve wheel tie bolt clamping forces… and improve prevention against corrosion’. The service bulletin also recommended a new type of anti-seize compound, which was adopted by the maintenance facility prior to the occurrence. Following the occurrence, this new tightening method was made mandatory.

Prior to the occurrence, the manufacturer had updated the CMM to explicitly prohibit the application of any product to the mating faces of the wheel halves. Illustrations were included to demonstrate the proper application of anti-seize compound. A warning message regarding lubricant on the mating faces was also engraved on the wheels themselves. Since the occurrence, one of the maintenance facilities reported a change in nut design had resulted in fewer nuts failing their breakaway torque check.

Eddy current inspections[4] of the outer and inner wheel halves were mandated every tyre change. However, the CMM indicated that these were localised to the bead seat area of the wheel. These inspections would therefore not identify the fatigue cracks observed in this occurrence, which were at a different location. General inspections of Virgin wheels were performed every six tyre changes. These inspections included a visual inspection of each wheel half and dye penetrant inspection. It is not clear whether these tests would have revealed cracking such as that found in this occurrence. Regardless, the wheel ruptured after three tyre changes, so the inspection had not yet been performed.

Operator inspections for loose tie bolts

Following the main wheel failure, Virgin performed a fleet-wide inspection on this wheel-type. Two other wheels in service at that time had tie bolts loose enough to be moved by hand. One of these wheels was relatively new, and had not yet required a tyre change.

As another post-incident preventative safety measure, the maintenance facilities applied torque seal to all tie bolt assemblies after each tyre change. The torque seal provided a visual indication of loosening tie bolt assemblies without any additional equipment. All wheels were also inspected at regular intervals, with the longest time between inspections being 28 days in service. This interval was selected so that the majority of wheels would be inspected at least once before a tyre change (approximately 40 days in service).

When a wheel was found with broken torque seals, the wheels and tie bolt assemblies were visually inspected for damage and their breakaway torques were tested. Nuts were replaced if they failed their torque check and undamaged assemblies were put back into service. No other loose tie bolts were found following the initial fleet inspections until July 2017. From July 2017 to August 2018, the wheel inspections found:

  • ten more wheels with at least one broken torque seal, including six with multiple broken torque seals
  • broken torque seals on wheels that had come from each of Virgin’s maintenance facilities
  • three wheels exhibiting tie bolts with broken torque seal, despite being above the minimum allowable torque
  • one instance where a tie bolt with unbroken torque seal was below the minimum allowable torque.

The bolt with unbroken torque seal could indicate that not all tie bolt assemblies left the maintenance facilities with the appropriate torque. Conversely, the broken torque seals on correctly torqued nuts serve as confirmation the tie bolt assemblies loosened in service despite being appropriately tightened.

Since September 2018, there have been no more broken torque seals found during Virgin’s inspections.

Boeing advice on tie bolts loosening in service

In 2018, Boeing released a bulletin to its fleet, recognising several wheel failures involving this type of wheel and acknowledging that it was the result of tie bolt assemblies loosening in service. The publication stated:

As the nuts unscrew from the bolts, the wheel halves start to separate under the influence of tire pressure and ground loads. Eventually the wheel halves flex to a sufficient amount that the wheel ruptures…

The bulletin also stated:

The mechanism that causes the nuts to unscrew is not well understood and has been difficult to reproduce on a dynamometer during lab testing.

The bulletin described wheel-types from two different manufacturers, however both wheels had a similar single-web design, with the axle bearings contained within one wheel half. Boeing believed that the issue was unique to these two wheel-types. The bulletin stated that if the preload was ‘less-than-optimal, the nuts may start backing out, or ’unscrew’ from the bolts as the wheel rolls under load.’ Boeing identified two issues that were associated with loosening. From the digest:

Bolt preload. Strict adherence to the bolt/nut tightening procedures has been shown to minimize the likelihood of bolt loosening.

Bolt thread lubricant. Testing and in-service experience has shown that certain thread lubricants are more likely than others to result in nut loosening.

Wheel manufacturer service bulletins

The wheel manufacturer released two optional service bulletins that mitigated the likelihood or consequence of tie bolts loosening in service.

The first bulletin was released prior to the occurrence in July 2016, to ‘ease main wheel deflation in case of broken or missing tie bolts’ (SB C20626-32-014). This had not been implemented on the ruptured wheel. The service bulletin introduced a replacement for the inner half-wheel. The new part included grooves along the mating face of the half-wheel, so that any movement between the two halves would allow air to escape and result in the gradual deflation of the wheel. Based on estimations from the manufacturer, the new half-wheel currently has a 55-60 per cent adoption rate, on a global stock of approximately 12,000 in-service wheels.

The second service bulletin added lockwire on to the tie bolt assemblies to prevent any loosening while in service (SB C20626-32-016). This bulletin was released on 4 January 2018, however the wheel manufacturer advised that bulletin was not released in response to this occurrence.

Previous occurrences

The wheel manufacturer advised that globally, there have been three other cases in which this type of wheel has fractured, and in each case the manufacturer assessed that the fracture initiated from a loss of bolt tension. In two of those three cases, the manufacturer believed the loss of bolt tension was caused by interposition product (grease or anti-seize compound) between the mating faces of the wheel. VUH was the first and only occurrence in Australia (noting that Virgin and Qantas use this wheel-type on their 737 NG fleet).

While the number of wheel failures is known, the number of instances of loosening tie bolt assemblies could not be determined or accurately estimated. CMM instructions for disassembling the wheel did not include any instruction on recording bolt torque or inspecting for loose bolts. Instances of loosening tie bolts in Virgin’s fleet have been recorded since the occurrence, but in the global fleet the numbers are unknown.

__________

Occurrence event

The location of fatigue crack initiation in the wheel was coincident with areas of high service stress and there was no evidence of corrosion or manufacturing defect. A majority of the tie bolt assemblies on the fractured wheel were found to be loose, and nuts were found to be backing off on appropriately-torqued tie bolt assemblies on other wheels during service. Previous occurrences of wheel fracture have also been associated with loss of bolt tension. It was therefore most likely that tie bolt assemblies loosening in service resulted in the fatigue cracking and rupture of VUH’s left main wheel.

The loose tie bolt assemblies were likely a result of interposition product (grease or anti-seize compound) on the mating faces of the wheel halves. This prevented the halves from abutting squarely against one another when tightening the tie bolt assemblies. The wheel halves were then able to move relative to one another while in service, causing the tie bolt assemblies to loosen, reducing the clamping forces and inducing cyclic stresses.

Prevention or detection of tie bolt loosening

All of the possible reasons Boeing and the wheel manufacturer provided for the wheel ruptures related to having a suboptimal clamping force between the two hub halves, resulting in the failure mechanism described above. Prior to this occurrence, the wheel manufacturer had updated the component maintenance manual to explicitly prohibit interposition product between wheel halves. That update did not prevent this occurrence and the operator had 12 further instances of tie bolts loosening in service. However, since the manufacturer visited both of the organisations maintaining Virgin’s wheels, they have had no additional occurrences.

While actively preventing interposition product between the wheel halves appears to have been effective at reducing instances of loose tie bolts, there are other mechanisms that could reduce wheel clamping force. For example, since the occurrence there has been at least one instance of a wheel entering service with a bolt that was below the minimum required torque. Clamping force will also be affected by broken or missing tie bolts, which was the hazard addressed by the manufacturer through the introduction of hub grooves for safe tyre deflation.

At the time of publication there were no mandatory inspections capable of reliably detecting loose or missing tie bolt assemblies in service, between tyre changes. Those on the outer main wheels would not be readily observable due to the presence of a hubcap. In the absence of inspections, the two optional service bulletins (grooves for safe deflation, and lockwire on the tie bolt nuts) existed to prevent wheel ruptures and subsequent adverse outcomes, however their optional nature reduced the service bulletins’ effectiveness as risk controls.