Air Accident Investigation Branch Research Articles

What Went Wrong?

Governments should create IT accident investigation boards for the exact same reasons they have done so for ships, railroads, planes, and in many cases, automobiles. Denmark got its Railroad Accident Investigation Board because too many people were maimed and killed by steam trains. The UK's Air Accidents Investigation Branch was created for pretty much the same reasons, but, specifically, because when the airlines investigated themselves, nobody was any the wiser. Does that sound slightly familiar in any way?

The Future of Aircraft Feedback Information: Maintainability Allocation Methodology

In this paper, the author looks at certain areas of maintainability prediction process where missteps or misapplications most commonly occur. This research attempts to utilise the aircraft maintenance historical data and information (i.e. feedback information systems). Aircraft feedback information such as Service Difficulty Reporting System (SDRS) and Air Accidents Investigation Branch (AAIB) contains various types of information that could be used for future improvement rather than just the failure elements, as well as to help identify the critical and sensitive components that need more attention for further improvement. The study shows that the aircraft maintenance related feedback information systems analyses are very useful for deciding the maintainability effectiveness; these include planning, organizing maintenance and design improvement. There is no doubt that historical data information has the ability to contribute an important role in design activities. The results also show that maintainability is an importance measure that can be used as a guideline for managing efforts made for the improvement of aircraft components.

Investigating the Truth of Heinrich's Pyramid in Offshore Helicopter Transportation

Several hazardous industries have embraced Heinrich's premise that incidents of negligible safety consequences are precursors to accidents in a statistical sense. However, in few such industries has research verified the truth of that assumption. This paper explores the relationships between accidents and reported incidents in the context of oil and gas–related offshore helicopter operations by using the accident investigation reports published by the UK Air Accident Investigation Branch and the incidents filed under the British Mandatory Occurrence Reporting Scheme between 1997 and 2010. Classification frameworks were developed to enable the independent analysis of accidents and incidents in relation to specific variables of interest. Frequencies and statistical associations that could have indicated the precursor relationship were explored. From the results of the analysis, the paper highlights potentially severe shortcomings in the assumptions underpinning incident data collection as well as the process with which incident data are generated. For example, the paper unveils the existence of sudden failures that cannot be reliably anticipated or reported and draws attention to a potentially flawed incident-reporting culture. Given the results, the paper informs stakeholders in the industry of specific initiatives to ensure that the right lessons are learned from past occurrences (e.g., through ways of collecting incident data that will not rely solely on reporters) and how these could be used to inform future interventions, for example, through the analysis of potential consequences of incidents, as a complement to the analysis of frequencies.

A Two-Phase Method of Detecting Abnormalities in Aircraft Flight Data and Ranking Their Impact on Individual Flights

A two-phase novelty detection approach to locating abnormalities in the descent phase of aircraft flight data is presented. It has the ability to model normal time series data by analyzing snapshots at chosen heights in the descent, weight individual abnormalities, and quantitatively assess the overall level of abnormality of a flight during the descent to a given runway. The method models normal approaches to a given runway (as determined by the airline's standard operating procedures) and detects and ranks deviations from that model. The approach expands on a recommendation by the UK Air Accident Investigation Branch to the UK Civil Aviation Authority. The first phase quantifies abnormalities at certain heights in a flight. The second phase ranks all flights to identify the most abnormal, each phase using a one-class classifier. For both the first and second phases, i.e., the support vector machine (SVM), the mixture of Gaussians and the K-means one-class classifiers are compared. The method is tested using a data set containing manually labeled abnormal flights. The results show that the SVM provides the best detection rates and that the approach identifies unseen abnormalities with a high rate of accuracy. The feature selection tool F-score is used to identify differences between the abnormal and normal data sets. It identifies the heights where the discrimination between the two sets is largest and the aircraft parameters most responsible for these variations. The method presented adds much value to the existing event-based approach.

Work of the UK Helicopter Task Group

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 140760, ’The Work of the UK Helicopter Task Group,’ by Jessica Burton, Oil & Gas UK, originally prepared for the 2011 SPE European Health, Safety, and En vironmental Conference in Oil and Gas Exploration and Production, Vienna, Austria, 22-24 February. The paper has not been peer reviewed. The Helicopter Task Group (HTG) was created by the UK oil and gas industry in April 2009 to address helicopter-safety issues, including those arising from the tragic helicopter crash off the northeast coast of Scotland on 1 April 2009. The task group included representatives from offshore operators and contractors, including those involved in the incident, as well as Oil & Gas UK, the offshore workforce, helicopter-operator companies, regulators, emergency-response organizations, and trade unions. Introduction The HTG was created to address cross-industry issues about helicopter safety, including those arising from the fatal helicopter crash off the northeast coast of Scotland on 1 April 2009. The purpose of the HTG was to act on behalf of the industry as a communications focal point for sharing information, advice, and learning across the industry and with other stakeholders on matters arising from this and other helicopter accidents, including assisting the implementation of any recommendations from the Air Accidents Investigation Branch (AAIB) inquiries. The group also defined possible policies and practices to be recommended to the Board of Oil & Gas UK for approval and consequent implementation on a pan-industry basis. In doing this, it was supported by existing industry workgroups and advisory teams. The group met every 4 weeks from April 2009 to June 2010. The full-length paper is designed to summarize the key issues that the task group was involved in over that period, some of which had been ongoing work for a number of years, and what changes have been made to the offshore industry and aviation safety as a result of the cooperation between the task group, wider aviation community, existing industry bodies, regulators, and emergency-response organizations. HTG Work Plan The HTG identified a number of key aviation-safety issues at its first meet-ing in April 2009, which would form the basis of its work plan. Although many potential projects could have been chosen, it was decided that—to ensure that the group could work effectively and deliver results in a manageable time frame—only a set number of priority items would be focused on. These work areas initially were linked to recommendations arising from the lessons learned in the two helicopter incidents that occurred in the UK continental shelf (UKCS) in early 2009. As the group progressed, other work areas were identified, including some linked to lessons learned in other incidents around the world. Summary of Key Work Areas and Progress Made The following is a summary of each of the key work areas or projects overseen by the task group, and the status of each by June 2010 when the group was closed formally and its work was handed over to a new group.

Credible investigation of air accidents

Within the United Kingdom the Air Accidents Investigation Branch (AAIB) has been used as a model for the other transport modes accident investigation bodies. Government Ministers considered that the AAIB’s approach had established the trust of the public and the aviation industry in its ability to conduct independent and objective investigations. The paper will examine the factors that are involved in establishing this trust. They include: the investigation framework; the actual and perceived independence of the accident investigating body; the aviation industry’s safety culture; the qualities of the investigators and the quality of their liaison with bereaved families those directly affected by the accidents they investigate.

The AASK Database V3.0: A Database Of Human Experience During Aircraft Evacuation Incidents

This paper describes recent developments with the Aircraft Accident Statistics and Knowledge (AASK) database. The AASK database is a repository of survivor accounts from aviation accidents developed by the Fire Safety Engineering Group of the University of Greenwich with support from the UK CAA. Its main purpose is to store observational and anecdotal data from the actual interviews of the occupants involved in aircraft accidents. Access to the latest version of the database (AASK V3.0) is available over the Internet. AASK consists of information derived from both passenger and cabin crew interviews, information concerning fatalities and basic accident details. Also provided with AASK is the Seat Plan Viewer that graphically displays the starting locations of all the passengers – both survivors and fatalities - as well as the exits used by the survivors. Data entered into the AASK database is extracted from the transcripts supplied by the National Transportation Safety Board in the US and the Air Accident Investigation Branch in the UK. The quality and quantity of the data was very variable ranging from short summary reports of the accidents to boxes of individual accounts from passengers, crew and investigators. Data imported into AASK V3.0 includes information from 55 accidents and individual accounts from 1295 passengers and 110 crew.

Flight deck indication of health monitoring data—a critique

In September 1995 there was an incident involving an AS332L Super Puma helicopter over the North Sea. This followed the onset of high vibration due to the fatigue failure of a tail rotor blade retaining hinge. This was the first major vibration incident involving a helicopter fitted with a health and usage monitoring system (HUMS). The UK Air Accidents Investigation Branch made a number of recommendations. One was that the UK Civil Aviation Authority (CAA) should develop the concept of providing a flight deck display of health monitoring information to the flight crew. The CAA asked the Helicopter Health Monitoring Advisory G roup (HHM AG) (an industry body that advises the CAA) to consider the issue. This paper will examine the findings of the H HMAG working group and discuss the practicality of such systems in an operational environment.

Proving properties of accidents

Abstract Accident reports are produced by regulatory and commercial authorities, such as the UK Air Accident Investigation Branch and the US National Transportation Safety Board, in response to most major accidents. These documents are intended to ensure that disasters do not recur. They, typically, contain accounts of the human and system failures that lead to major accidents. These descriptions are then used to identify the primary and secondary causes of the failure. Finally, recommendations are made so that the operators and regulators of safety-critical systems can avoid future accidents. Unfortunately, it is often difficult for readers to trace the way in which particular conclusions are drawn from the many hundreds of pages of evidence in these reports. Natural language arguments often contain implicit assumptions and ambiguous remarks that prevent readers from understanding the reasons why a particular conclusion was drawn from a particular accident. In contrast, this paper argues that mathematical proof techniques can be used to support the findings of accident investigations. These techniques enable analysts to formally demonstrate that a particular conclusion is justified given the evidence in a report. In doing so, it is possible to identify missing pieces of evidence, to identify ambiguities and to determine which items of evidence are critical to particular lines of argument. The later sections of this paper then introduce Conclusion, Analysis and Evidence diagrams. These can be used to communicate the results of a formal analysis. The intention is not to replace the natural argumentation structures that are currently used in accident reports. Rather, our aim is to increase our confidence that particular conclusions are well supported by the evidence that is presented within a report. Finally, we show how CAE diagrams may be used in conjunction with design rationale techniques that have been proposed to support the design of safety-critical applications. This helps to ensure that findings about previous failures are propagated into the subsequent development of future systems.

The management of aircraft passenger survival in fire

The prime factors influencing survivability from 10 major fire-related public transport aircraft accidents were assessed. Regulatory requirements were assessed against derived criteria and alternate concepts evaluated to identify a preferred strategy for enhanced survival; the provision of passenger protective breathing equipment (PPBE) was part of the twin strategy selected. PPBE tests conducted by the UK Air Accidents Investigation Branch using lung simulators and semi-controlled complex challenge combustion atmospheres generated from defined mixtures of cabin interior materials indicated that Hopcalite filters could provide satisfactory protection against carbon monoxide, hydrogen cyanide, hydrogen fluoride, hydrogen chloride, nitrogen oxides, sulphur dioxide, ammonia, acrolein, and other hydrocarbon compounds, for periods up to 30 min. Filtered levels of carbon dioxide (CO 2) could be maintained within a 5% limit (inhaled atmosphere + dead space) against such atmospheres containing up to 4% CO 2. Concentrations of oxygen downstream from the filters were up to some 1.0% above that present in the challenge atmospheres. Separate lung simulator tests on breathable gas (oxygen) hoods indicated that satisfactory respiratory protection could be provided for periods of up to 31 min. A possible filter modification of the passenger oxygen mask concept is discussed. It is recommended that research should be emphasized on the development of a means (e.g. PPBE) for providing in-flight smoke protection for passengers.

Management of Disasters and their Aftermath

Ed W Angus Wallace, John M Rowles, Christopher L Colton BMJ Publishing Group, pounds sterling36, pp 314 ISBN 0 7279 0841 3 Having previously been fascinated by air disasters and read, at length, various reports on them, I automatically assumed that Management of Disasters would be the usual self congratulatory internal report. I was wrong. I read this book from cover to cover, in two evenings, and found it fascinating. The details of how the Air Accident Investigation branch operates, and the analysis of both survivors' and victims' placement in an aircraft, kept me enthralled. They also helped me understand the practical difficulties in arranging for the investigations to occur—for instance, setting up a site for a major disaster mortuary with …

Using a formal language to support natural language in accident reports

Accident reports written by official bodies, such as the Air Accident Investigation Branch of the United Kingdom's Department of Transport, are produced in response to all major civil aircraft accidents or incidents. There are many statutory, legal and commercial implications that rest on the analysis, conclusions and recommendations that these reports contain. Air accident reports usually follow a standard format of synopsis followed by factual information, including history of flight and the systems involved, followed by analysis and conclusions. Finally, there are safety recommendations aimed at preventing a recurrence of the accident. Natural language is the primary means of communicating all of these findings. In requirements engineering there is an increasing recognition that natural language is not always an adequate means of expressing some of the detailed reasoning associated with the causal analysis of complex systems. Recent work in software engineering has explored the use of formal, mathematically based, techniques to help to gain the required level of clarity and precision. It is argued that accident reports, like requirements documents, could benefit by the use of formal techniques to complement the usual natural language descriptions. In this paper one specific accident report is considered. The limitations of its natural language descriptions are examined and the use of a Petri Net notation to help to elucidate its ambiguities is explored

Cabin Integrity and Passenger Safety

RECENT conference statements and the publication of the Kegworth report by the Air Accident Investigation Branch (AAIB) have highlighted many issues affecting passenger safety. Yet again, emphasis has been laid on the very welcome reduction in the statistical rate of jet transport accidents over the past few decades and the lack of a corresponding improvement in the survival rate in these accidents.

KEEPING BIRDS IN HAND

Modern aircraft engines are designed and built to be resistant to multiple bird strikes from birds of up to 4.5 lb in weight. The United Kingdom CAA has played a leading role in developing enhanced engine certification requirements, and the U.S. National Transportation Safety Board and U.K. Air Accident Investigation Branch recommendations have served further to emphasize the need for such activity. However, it would be far better to try and reduce the chances of bird strikes from happening in the first place. This article discusses the increasing risk factor bird strikes pose to aircraft safety, focusing on the implementation of wildlife management controls in order to minimize bird habitat attractants and better manage bird populations in the vicinity of airports.