Research and Analysis Report

Significant attention has been given in the literature to aviation safety, with emphasis on the importance of developing and maintaining resilience to accidents.  To date, this attention has remained at the conceptual level, with comparatively little empirical research undertaken to test the validity of concepts put forward in the literature. This report presents the findings of a qualitative study, investigating the factors perceived to facilitate safety culture and institutional resilience within airlines.  Thirty-two senior managers, drawn from Safety Departments and Flight Operations Divisions, participated in the research, representing 12 airlines operating in the Asian and Pacific regions.  Data was obtained through semi-structured interviews with participants, based on questions relating to terms contained in James Reason's Checklist for Assessing Institutional Resilience.

The checklist provided a useful framework for obtaining data; however, some terms reflected exclusivity in identifying factors that impact on organisational resilience, and others significantly overlapped in their application to the airline industry.  Themes emerging from the findings include the importance of leadership roles undertaken by the board, senior management, chief pilots and safety departments, and the influence of both formal and informal performance management systems.  Analysis of the findings addresses the implications for Reason's checklist, and identifies those factors that are not on the checklist but perhaps ought to be.  The emergence of a model which may be empirically tested through quantitative design is considered, along with other recommendations for future research.  In conclusion, strategies are presented, drawn from the data, which support the presence or absence of safety cultures within the airline industry and impact on ability to assess institutional resilience.

Civil aviation safety is based on managing the safety of knowledge of things that can affect the safety of flight. One of these sets of knowledge is confidence that the facilities at the destination will be good enough to give confidence of a safe landing. Weather at the destination can affect the safety of a landing. Detailed historical records are kept of weather observations and weather forecasts. This study has analysed the level of statistical confidence that has been achieved with destination weather forecasts under various conditions. It has also looked at other mechanisms that are or could be used to reduce the risk in addition to the existing methods.

This study provides an overview of aircraft cabin safety communications in Australia, in terms of effectiveness, passenger attitudes to such communications and opportunities that exist for improvement.

Most passengers agreed that paying attention to cabin safety communications is important. However, results revealed that behaviours do not always match this perception. Perceived relevance of safety information and frequency of travel were found to be significant factors affecting passenger attitudes and behaviours. High levels of message recognition, combined with excessive levels of confidence in personal ability to perform safety actions may be key drivers of reduced perceptions of relevance.

Passenger attention levels to safety communications were found to be generally low. Of all communication types tested, the safety briefing was most prone to perceptions of reduced relevance through repeated exposure, while very low attention levels and perceptions of content establish safety cards as being generally ineffective.

Analysis identified that low levels of passenger attention to safety communications results from overconfidence, superficial familiarity with messages, issues relating to the way safety content is presented, perceptions of substitutability between the card and briefing and social norms present in the aircraft cabin.

A framework for cognitive processing of cabin safety communications is presented. The framework identifies that passenger behaviours may be negatively influenced by perceptions that it is socially undesirable to pay attention to safety information. Changing normative and attitudinal beliefs represents the greatest opportunity to improve communication effectiveness.

Key opportunities are identified to improve cabin safety through enhancement of communications. These recommendations include tailoring communications to the needs of specific passenger profiles, providing additional information to passengers, improved design guidelines, regular content variation and use of communications specialists in safety media design.

Area navigation global navigation satellite system (RNAV (GNSS)) approaches have been used in Australia since 1998 and have now become a common non-precision approach. Since their inception, however, there has been minimal research of pilot performance during normal operations outside of the high-capacity airline environment. Three thousand five hundred Australian pilots with an RNAV (GNSS) endorsement were mailed a questionnaire asking them to rate their perceived workload, situational awareness, chart interpretability, and safety on a number of different approach types.

Further questions asked pilots to outline the specific aspects of the RNAV (GNSS) approach that affected these assessments.

Responses were received from 748 pilots, and answers were analysed based on the aircraft performance category¹. For pilots operating Category A and Category B aircraft (predominantly single and twin-engine propeller aircraft), the RNAV (GNSS) approach resulted in the highest perceived pilot workload (mental and perceptual workload, physical workload, and time pressure), more common losses of situational awareness, and the lowest perceived safety compared with all other approaches evaluated, apart from the NDB approach. For pilots operating Category C aircraft (predominantly high-capacity jet airliners), the RNAV (GNSS) approach only presented higher perceived pilot workload and less perceived safety than the precision ILS approach and visual day approach but lower workload and higher safety than the other approaches evaluated. The different aircraft category responses were likely to have been due to high-capacity aircraft having advanced automation capabilities and operating mostly in controlled airspace. The concern most respondents had regarding the design of RNAV (GNSS) approaches was that they did not use references for distance to the missed approach point on the approach chart and cockpit displays. Other problems raised were short and irregular segment distances and multiple minimum segment altitude steps, that the RNAV (GNSS) approach chart was the most difficult chart to interpret, and that five letter long waypoint names differing only by the last letter can easily be misread.

1. Aircraft performance approach categories are determined by multiplying the aircrafts stall speed in the approach configuration by a factor of 1.3. See Section 3.1.

Transport accidents are a leading cause of injury, both fatal and non-fatal. The primary purpose of this publication is to provide a broad overview of serious injury due to transport accidents in Australia in the one-year period 2003-04, the latest year for which data are available.

Serious injury is defined for this report as an injury which results in the person being admitted to hospital, and subsequently discharged alive either on the same day or after one or more nights stay in a hospital bed (i.e. deaths are excluded). This report presents estimates of the numbers of persons seriously injured in Australia due to transport accidents in the one-year period 2003-04. All modes, air, sea, road and rail, are included.

Publication available from the Australian Institute of Health and Welfare website(Opens in a new tab/window)

Transport accidents are a leading cause of injury, both fatal and non-fatal. The primary purpose of this publication is to provide a broad overview of serious injury due to land transport accidents in Australia in the one-year period 200304, the latest year for which data are available. The main focus is on accidents involving road vehicles travelling on public roads (called travelling in traffic). Road vehicles include motor vehicles, pedal cycles and other road vehicles such as trams, animals or animal-drawn vehicles (when they travel on the road).

Serious injury is defined for this report as an injury which results in the person being admitted to hospital, and subsequently discharged alive either on the same day or after one or more nights stay in a hospital bed (i.e. deaths are excluded).

This report presents estimates of the numbers of persons seriously injured in Australia due to land transport accidents, including road traffic crashes, in the one-year period of 2003-04. Trends in injury rates in road traffic crashes are examined over a five-year period, 1999-00 to 2003-04.

Publication available from the Australian Institute of Health and Welfare website(Opens in a new tab/window)

The ATSB carried out a safety deficiency investigation in accordance with powers under section 19CB (1) (d) of the Air Navigation Act 1920.

SAFETY DEFICIENCY

An allegation was made to the ATSB that Australian registered Boeing 747-300 aircraft operating from Bangkok airport in Thailand were failing to meet take-off performance requirements. A 'specified' flight was cited as demonstrating that the aircraft had not complied.

Comprehensive analysis of data from the 'specified' flight, as well as data from other flights departing Bangkok under similar conditions, was undertaken. Documentation provided by the crew of the 'specified' flight was also analysed. The data included brakes release to V_R (take-off rotation speed); V_R to V_LOF (aircraft lift off speed); V_LOF to 35 feet; total distance from brakes release to V₂ (take-off safety speed) at 35 feet.

Appropriate sections of the Boeing and the operator's Flight Crew Training Manuals (FCTM) were reviewed and the ATSB concluded that the actual take-off data correlated with the Flight Crew Training Manual information.

For certification, the Boeing 747-300 aircraft is required to be able to sustain an engine failure at or after a specified speed (V₁) at its maximum take-off weight and safely climb on the thrust of the remaining three engines. V₁ is the decision speed at, and below which take-off can be aborted and the aircraft stopped within the runway confines. It is also the speed at and above which the take-off can safely be continued should the critical engine become inoperative, where the critical engine is the engine that would most adversely affect the performance or handling qualities of the aircraft.

Analysis of the recorded data confirmed that the 'specified' take-off from Bangkok was with four engines operating. No evidence was found to suggest that the aircraft concerned did not meet the certified requirements for take-off performance.

Nothing in the cases examined suggested that the aircraft would not be able to safely climb from the runway on three engines if an engine had failed at or after reaching V₁ speed. Had an engine failure occurred before V₁, by definition the aircraft would have been able to stop within the runway confines.

Formulae from Boeing Jet Transport Methods were used to derive actual take-off distance of the 'specified' take-off. Digital Flight Data Recorder (DFDR) and Quick Access Recorder (QAR) data were used to establish time from brakes release to rotate, time from rotate to lift-off, time from lift-off to a height of 35 feet by radar altimeter, and to calculate take-off distance. Data from the flights analysed showed the aircraft met the certification requirements for take-off performance.

Calculations by Boeing and the operator were assessed by performance engineers from the Civil Aviation Safety Authority. Subsequent independent review of the data, including comparison with the ATSB's calculations, verified the accuracy of those calculations. Again, no evidence was found to suggest that the aircraft did not meet certified performance requirements.

The ATSB was not able to source any information to quantify any in-service experience with the worldwide Boeing 747-300 fleet to suggest that there has been any deviation from the aircraft performance levels indicated in the approved Aircraft Flight Manual.

There is also no evidence that a dangerous situation as described in the report of the alleged safety deficiency has occurred in the 12-month period to October 2000. The ATSB concluded that Boeing 747-300 aircraft are meeting scheduled performance requirements.

Occurrence Date: 14 NOVEMBER 1999
Registration No: VH-EBX
Model: B747-300
Manufacturer: Boeing Co

The reporting of aviation safety occurrences enables the Australian Transport Safety Bureau (ATSB) to investigate accidents and serious incidents and monitor safety through the analysis of any trends. On 1 July 2003 the Transport Safety Investigation Act 2003 came into effect, introducing the terms immediately reportable and routine reportable matters (IRMs and RRMs, respectively).

This report examines trends in IRMs that involved regular public transport operations and provides a context for interpreting any changes over time. The aim is to inform the aviation community of any important safety trends, and to provide the travelling public with a better appreciation of the types of occurrences that are reported to the ATSB.

The study found that high-capacity regular public transport operations dominated air transport activity, and consequently dominated the reports of IRM occurrences. Furthermore, activity for high-capacity air transport operations, measured by flying hours and movements, increased over the period studied.

The IRM categories examined were either stable or trended downwards between mid 2001 and mid 2006. Violations of controlled airspace reduced over the period while occurrences involving a fire, explosion or fumes and crew injuries or incapacitation also decreased, but only marginally. Other IRM categories such as contained engine failures and fuel exhaustion events were rare, or absent. The exception was breakdowns of separation (BOS) and airprox events, where occurrence numbers went up. However, the rate did not increase relative to the number of movements, suggesting that the increase was largely linked to increased activity.

This review highlighted the consistent reporting culture of the air transport sector and the air traffic service provider, and provided encouraging data concerning the general state of safety in regular public transport operations.

The purpose of this publication is to provide a national overview of serious non-fatal injury in Australia due to transport accidents involving a railway train in the period 1999-00 to 2003-04, including level crossing accidents. The definition of transport injury used in this report excludes injuries given an external cause of intentional self harm, assault or undetermined intent (terms that are defined in the report).

This report includes all injuries that were serious enough to require hospitalisation but did not result in death.

Publication available from the Australian Institute of Health and Welfare website(Opens in a new tab/window)

Reciprocating-engine powered low-capacity transport aircraft (8 to 10 passengers) provide an important public transport connection throughout regional Australia. In the period January 2000 to December 2005, twenty powertrain structural failures of high-power (300 to 375 brake horsepower) horizontally-opposed, reciprocating engines were associated with air safety occurrences reported to the ATSB. These occurrences ranged in severity from; in-flight engine shutdown; engine failure and forced landing; engine failure combined with in-flight fire and fracture of both upper engine mounts; to the fatal accident of a regular public transport flight following the structural failure of both engines to ditching at night. It is evident that the reliability of high-power reciprocating engines is an important requirement for the safe operation of this class of aircraft. This research investigation is a study of the factors that affect reciprocating engine reliability.

The study found that powertrain structural failure was not restricted to one engine model, one engine manufacturer, or one powertrain component. The events that initiated sequences that led to engine in-flight failure could be grouped into three categories: combustion chamber component melting; bearing breakup; and powertrain component fatigue cracking. Analysis of the factors that were associated with each category of initiating event revealed that powertrain component reliability is affected by the development of shockwaves during combustion, the response of bearings to boundary lubrication and out-of-plane alternating loads, the increase in component alternating stress magnitudes, and creation of stress-concentrating features in components during engine operation. These factors may act singly, but on many occasions it is the synergistic effect of the presence of multiple factors that result in a sequence of events ending with engine in-flight failure.

The recurrence of powertrain component structural failure events suggests that the corrective actions that are a part of the airworthiness assurance system may have been ineffective. Corrective action is dependent on accurate analysis and feedback. It is evident that analysis is affected by the complexity of reciprocating engine systems and feedback requires a broad view of the interaction of systems and a detailed view of the components of a system.