A rare engine malfunction on a Boeing 747-400 reminds operators to be alert to signs of wear and fatigue.

A Qantas Boeing 747-400 on a flight between Sydney and Singapore on 9 May 2011 experienced a malfunction in one of its engines that led the crew to shut it down. The aircraft continued safely to Singapore.

Operators of Rolls Royce RB211-524 engines have been alerted to the potential for wear and degradation of the IP turbine blade interlocking shrouds...

Indications from the engine included an increase in exhaust gas temperature and vibrations, which continued after the crew reduced the engine’s thrust. The ATSB found that the problem resulted from the failure and separation of a single intermediate-pressure (IP) turbine blade.

The blade had fractured following the initiation and growth of a fatigue crack from an origin area near the blade inner root platform. The manufacturer undertook detailed modelling and analysis. While it has not fully identified the root cause of the fracture, wear and loss of material from the turbine blade interlocking shrouds may have reduced the rigidity and damping effects of the shroud, contributing to the high-cycle cracking and failure.

The engine manufacturer issued a non-modification service bulletin in October 2011. The Bulletin required operators to perform a once-around-the-fleet inspection of IP turbine blades for missing shroud interlock material by June 2012. The aircraft operator advised that they had completed inspections across their fleet with no instances of excessive wear detected.

Operators of Rolls Royce RB211-524 engines have been alerted to the potential for wear and degradation of the IP turbine blade interlocking shrouds, with the possibility that this mechanism, if not detected and addressed, could lead to turbine blade cracking and loss. Service experience has shown that the probability of a failure of an IP turbine blade failure is very low and while it may cause malfunctions necessitating shutdown, the risks to flight are minor.

Read the final report: In-flight engine malfunction – Boeing 747-438, VH-OJH, 100 km south-east of Bali International Airport, Indonesia, on 9 May 2011

The ATSB’s Chief Commissioner, Martin Dolan, has just published his latest blog post. 

In the post, Martin talks about 'No-blame' investigations and why they are important to improve the system of safety.

Read Martin’s post and contribute to the discussion at www.atsb.gov.au/infocus

A new ATSB research report examines the effectiveness of safety management systems (SMS) and provides important insights for operators and organisations. 

SMS refer to organisations having a systematic approach to managing safety, including organisational structures, accountabilities, policies and procedures. They generally include common elements such as explicit management commitment to safety, appointment of key safety personnel, hazard identification and risk mitigation, safety investigations and audit, and safety performance monitoring. 

This research is especially timely because aviation, marine and rail industries have all recently incorporated safety management systems into regulations and operations as a required way of managing safety. Although Australia’s transport industries’ SMS approach is following world’s-best practice, there has been little empirical evidence presented as support for how the SMS approach actually influences safety. 

Dr Matthew Thomas undertook a comprehensive search of the literature that exists around SMS, examining existing studies and comparing their findings. The review found that safety management systems do appear to reduce accidents and improve safety in high-risk industries. At present, however, there have only been a small number of quality evaluations and it is unclear as to whether any individual elements of a SMS have a stronger influence on safety than other elements. At the same time, it is clear that management commitment and appropriate safety communications do affect attitudes to safety. Transport organisations that provide an appropriate investment and commitment to a safety management system should receive a positive return on safety. 

Read the research report: XR-2011-002, A Systematic Review of the Effectiveness of Safety Management Systems, contains detailed descriptions of its methods and findings.

Robinson R22 helicopter pilots are being urged to regularly check and maintain their aircraft’s drive system following a fatal accident in North-West Queensland.

• ATSB investigation identifies a drive belt failure in a fatal accident of a Robinson R22 helicopter.
• R22 pilots and operators need to regularly check drive system for misalignment and abnormal wear.
• Importance reaffirmed of pilot proficiency in autorations in case of a loss of main rotor drive.

While mustering near Julia Creek on 9 May 2011, a Robinson R22 helicopter was flying close to the ground when it lost drive to the rotor system. This resulted in a high rate of descent before the helicopter hit the ground. The pilot, the only occupant of the helicopter, died in the accident.

As a result of the drive failure and operating conditions at the time, the pilot needed to make an autorotative landing from a low altitude and at minimal speed.

The ATSB found that two v-belts that transfer torque from the engine to the rotor system had failed. The damage to the forward v-belt indicated that it had partially dislodged from the drive sheave, resulting in significant damage to the belt. At some point, the v-belt fragmented, compromising the redundancy of the belt-drive system. Once the rear v-belt failed, all drive to the rotors was lost.

As a result of the drive failure and operating conditions at the time, the pilot needed to make an autorotative landing from a low altitude and at minimal speed. Autorotation is a descent with power off—the helicopter’s rotor system continues to rotate at about normal RPM as a result of the air flowing upwards through the main rotor system. There was limited time for the pilot to recognise the condition, respond accordingly and for the autorotation to develop. This resulted in a high rate of descent at impact.

The accident reaffirms the important advice in ATSB safety advisory notice AO-2011-060-SAN-001. The notice highlights the need for R22 helicopter pilots and operators to pay careful attention to the installation, maintenance and inspection of drive belts and other components of the helicopter’s drive system.

The accident also highlights the importance of pilot proficiency in autorotations during emergency situations. When performing autorotations, there are a number of factors that must be considered in planning and execution to achieve a successful outcome. The ATSB Research and Analysis Report into Helicopter Accidents 1969–88 includes useful information on the risks associated with autorotations.  

Read the final report: Collision with terrain - Robinson R22 Beta II, VH-DSD, 85 km north-west of Julia Creek, Queensland, on 9 May 2011

The ATSB’s Chief Commissioner, Martin Dolan, has just published his latest blog post. 

In the post, Martin talks about the ATSB’s investigative focus on human error and how good safety systems need to detect and manage errors when they do occur. Martin also emphasises the importance of human factors in the ATSB’s role to improve transport safety. 

Read Martin’s post and contribute to the discussion at www.atsb.gov.au/infocus

An incident at Mackay Airport has highlighted the potential distraction presented by portable communication devices, especially in the dynamic airside environment.

On 29 June 2012, a Piper PA-31 Navajo aircraft, took off from runway 05 at Mackay Airport. At that time, an Airport Safety Officer (ASO) was conducting an airfield runway and lighting inspection in an airfield safety vehicle and moving in a north-westerly direction along runway 32. Despite an earlier air traffic control instruction to hold short of runway 05, the ASO was distracted by a telephone call and continued along runway 32, crossing runway 05. The Piper PA-31 passed over the airfield safety vehicle by an estimated vertical distance of 30 feet.

The ATSB reminds airport workers to always remain focussed during airside operations.

In 2012, Airservices Australia published the third edition of Third edition An Airside Driver's Guide to Runway Safety. This publication identified a range of safety measures intended to help reduce the likelihood of runway incursions, including information about situation awareness and communications. This publication also highlighted the importance of scanning runways before entering or crossing a runway.

A Department of Infrastructure and Transport road safety grant report titled In-car distractions and their impact on driving activities(Opens in a new tab/window) recognised that distraction from a mobile telephone may divert a driver’s mental and perceptual attention from the task of driving, and may increase response times to events.

The investigation report AO-2012-090 provides important advice about airside operations.

You can find this and other investigations in the ATSB’s Aviation Short Investigation Bulletin issue 13. The bulletin highlights valuable safety lessons for pilots, operators and safety managers.

Virgin Australia Airlines is reviewing their program to replace engine fuel feed crossfeed valves after a fuel imbalance on a flight from Gold Coast to Melbourne led to a declaration of a PAN and a diversion to Brisbane.

During climb, the crew observed that both engines were being supplied only from the right fuel tank, resulting in a fuel quantity difference between the left and right fuel tanks. The crew conducted the fuel leak engine checklist which confirmed that no engine fuel leak existed. With centre tank fuel available, the crew selected the centre tank pumps on, which resulted in the fuel imbalance stabilising.

Since the crew could not confirm fuel from the left tank could be used once the centre tank pumps were selected off, or that no fuel leak existed, they diverted to Brisbane. The aircraft landed without further incident.

An overhaul organisation inspected the engine fuel feed crossfeed valve and identified wear to the sealing materials and Teflon within the valve body as consistent with the existence of a leak within the valve. However, the overhaul organisation was unable to confirm whether the sealing material degradation would explain a high volume fuel leakage rate. 

...the crew selected the centre tank pumps on, which resulted in the fuel imbalance stabilising.

Virgin Australia Airlines had previously established an inspection program for the crossfeed valves in accordance with Boeing recommendations. The operator also has a program in place to replace existing crossfeed valves with a modified version at scheduled maintenance servicing.  This program is currently under review for acceleration.

You can find this and other investigations in the ATSB’s Aviation Short Investigation Bulletin issue 13. The bulletin highlights valuable safety lessons for pilots, operators and safety managers.

Read the final report: Fuel imbalance - Boeing 737, VH-VOL, 28 km south-west of Gold Coast Airport, Queensland, on 15 April 2012, which includes important advice.

The partial incapacitation of a pilot has shown how important it is for pilots to assess their own wellbeing and ability to fly, just as they do for their aircraft. 

In this case, the pilot and a flight nurse were flying from Sydney to Port Macquarie in a Raytheon B200 aircraft to pick up a patient.

The aircraft landed at Sydney and after shutdown the pilot became physically ill.

After departing Sydney, the pilot began to feel unwell, experiencing abdominal pain and nausea. After donning his crew oxygen mask, the pilot’s health improved and commenced a return to Sydney. During the descent, the pilot removed his oxygen mask and, soon after, he began to feel unwell again.

The aircraft landed at Sydney and after shutdown the pilot became physically ill. The pilot recovered from the illness about one week later. It was found that he most likely suffered viral gastroenteritis.

You can find this and other investigations in the ATSB’s Aviation Short Investigation Bulletin issue 13. The bulletin highlights valuable safety lessons for pilots, operators and safety managers.

The following resources provide more information about pilot incapacitation and help you to assess if you are fit to fly:

• Pilot Incapacitation: Analysis of Medical Conditions Affecting Pilots Involved in Accidents and Incident – 1 January 1975 to 31 March 2006
• Federal Aviation Administration Risk Management Handbook(Opens in a new tab/window)
• I.M S.A.F.E. Checklist(Opens in a new tab/window)

The Investigation report AO-2012-100 provides important advice on crew incapacitation.

A new aviation bulletin featuring 10 investigation reports has just been released by the ATSB. The Aviation Short Investigation Bulletin issue 13 covers short, office-based investigations.

The bulletin covers incidents and accidents involving jet, turboprop and piston aircraft, helicopters, and other vehicles. None of the accidents were fatal; however, one pilot sustained serious injuries and some of the aircraft were seriously damaged.

Short investigations cover incidents and accidents where the associated factors are usually well-understood and do not require more detailed investigations. Nonetheless, each investigation has the potential to produce important Safety Messages for pilots, operators and others in the aviation industry. The investigations also help the ATSB identify statistics and trends in air safety.

The incidents covered in the report include:

• Fuel imbalance – Boeing 737, VH-VOL (AO-2012-053)
• Breakdown of separation – Boeing 737-438 and Fairchild SA227 (AO-2012-087)
• Partial pilot incapacitation – Raytheon B200, VH-MSH (AO-2012-100)
• Breakdown of separation – Beech 200, VH-FDD and Beech 350, DINGO 008 (AO-2012-101)
• Aircraft proximity event – Piper PA-34, VH-PWQ and Cessna R182, VH-JYG (AO-2012-071)
• Aircraft proximity event – two Cessna 172S, VH-EWE and VH-EOP (AO-2012-099)
• Hard landing – Cessna 172S, VH-EOP (AO-2012-114)
• Collision with terrain – Robinson R22, VH-STK (AO-2012-091)
• Runway incursion – Perth airport safety vehicle (AO-2012-086)
• Runway incursion – Mackay airport safety vehicle (AO-2012-090)

Read the ATSB's Aviation Short Investigation Bulletin - Issue 13 (AB-2012-141)

Priorities for further improving the safety of Australia’s aviation, maritime and rail industries have been featured in the ATSB’s new online initiative, Safety Watch, released today in conjunction with the Chief Commissioner’s blog, In Focus.

ATSB Chief Commissioner, Mr Martin Dolan, said that while the ATSB has not seen any overall increase in risk to Australia’s transport safety, the transport community should consider opportunities to make safe transport systems even safer.

“The priority areas are based on accident and incident trends the ATSB has observed from investigation findings and occurrence reports,” Mr Dolan said.

“For aviation, there are opportunities for improvement in operations ranging from general aviation to high capacity airlines. Some of the risk areas involve wirestrikes, low-level flying, fuel management, handling of approach to land, and data input errors.

“Marine work practices continue to be a priority area, particularly in or around ships and loading areas. In addition, we’ve identified concerns with the challenging environment of coastal pilotage.

“For rail, the ATSB sees opportunities to improve the safety of workers on railway tracks following several accidents that occurred when track maintenance work was being undertaken.

“The ATSB has launched Safety Watch to help improve the transport community’s awareness of these safety priorities,” Mr Dolan said. “It provides a specific briefing for each of the identified issues, describing what the priorities are, and what can be done to manage the risk.”

Safety Watch is available at www.atsb.gov.au/SafetyWatch

InFocus is available at www.atsb.gov.au/InFocus