The primary objective of any investigation into an air safety occurrence is the prevention of an accident Sometimes an investigation will uncover a safety deficiency in the aviation system and recommendations are made to address the deficiency. At other times the details and circumstance of an accident or incident don't immediately uncover a safety deficiency or even provide immediate answers. However, the occurrence data is collected and stored in the ATSB database and may at some time in the future form part of a wider analysis of safety issues. A safety deficiency is defined in the…

Mountain wave and associated turbulence In Australia, mountain waves are commonly experienced over and to the lee of mountain ranges in the south-east of the continent. They often appear in the strong westerly wind flows on the east coast in late winter and early spring. Mountain waves are a different phenomena to the mechanical turbulence found in the lee of mountain ranges, and can exist as a smooth undulating airflow or may contain clear air turbulence in the form of breaking waves and 'rotors'. Mountain waves are defined as 'severe' when the associated downdrafts exceed 600 ft/min and/or…

The determination of blood ethanol concentration in a deceased pilot is an important part of the accident investigation. The finding of an elevated blood alcohol level in such a case may have significant implications, both medico-legal and social. It is therefore important to ensure that the finding of an elevated blood alcohol concentration is valid. It is known that micro-organisms involved in the process of putrefaction after death can produce alcohol, usually a mixture of ethanol and other volatile substances. This process occurs when a body is not refrigerated soon after death and is…

In 2004, there were two wirestrike accidents in New South Wales involving helicopters undertaking locust control operations. The first accident occurred in October 2004 near Forbes and resulted in minor injuries to one occupant and extensive damage to the helicopter. The second accident occurred in November 2004 near Dunedoo and resulted in the death of two occupants. A third occupant was seriously injured and there was extensive damage to the helicopter. A third accident, near Mudgee in November 2004, involved a helicopter that was being used for locust control, although the helicopter was…

The ATSB Annual Review documents ATSB's achievements and safety activities from 1 July 2004 to 30 June 2005 and outlines its business planning for 2005-2006. Executive Directors message In 2004-05 the ATSB benefited considerably from the funding boost for aviation investigations and aviation database replacement that was provided in the May 2004 Federal Budget. During the year, the Bureau recruited and commenced training 12 extra aviation safety investigators, instigated 109 aviation occurrence investigations and released 98 aviation investigation reports, up from around 60 in recent years.…

Recorded voice data, such as from cockpit voice recorders (CVRs) or air traffic control tapes, can be an important source of evidence for accident investigation, as well as for human factors research. However, most of the analysis has been based on subjective interpretation rather than the use of systematic methods, particularly when dealing with the analysis of crew interactions. Conversation analysis uses highly detailed and revealing transcriptions of recorded voice (or video) data that can allow deeper analyses of how people interact. When analysing recorded voice data, and especially for…

Boeing Commercial Aircraft Group, 747-436, G-BNLD 1. FACTUAL INFORMATION 1.1. History of the flight On the evening of March 1, 2002, Boeing 747-436 aircraft G-BNLD sustained the failure of the number-3 (right inboard) engine during a scheduled regular passenger transport flight from Sydney to Bangkok. The flight crew experienced vibrations and received an ENG 3 REVERSER engine indicating and crew alerting system (EICAS) message. The crew shut down the number-3 engine and completed checklist items before returning the aircraft to Sydney. An initial engineering examination found that a fan…

Boeing Commercial Aircraft Group, 747-436, G-BNLK 1. FACTUAL INFORMATION 1.1. Examination brief The disassembled components of an electric air-cooling fan (figure 1) were received by the ATSB Technical Analysis unit for examination and analysis of the damaged fan impeller. The fan unit had been fitted to a Boeing 747 aircraft (registration G-BNLK) to provide forced air circulation for a forward galley chiller unit. During the early stages of a flight on 10 August 2002, a small fire developed in the forward cargo compartment adjacent to this unit (figure 2). Physical and recorded evidence…

There has been a long standing interest among various transport safety organisations, researchers, other stakeholders and the public concerning the relative safety of various transport modes. Questions are often posed along the lines: on average, is travel in a light aircraft safer than a typical journey in a private car? or - what is the safety difference between motorcycle riding and driving a car ? Consideration of relative transport safety risks also has potentially important policy implications, particularly where contingent resource allocation or risk management decisions are involved.…

During a routine departure from Melbourne aerodrome, the inner left main landing gear wheel separated from a B727 aircraft (registration VH-TXH) and was later recovered near the aerodrome perimeter fence. Preliminary examination showed that the outer axle bearing had failed, allowing the wheel hub to move axially outward over the retaining nut and off the stub axle (figure 1).