The Analyst's analysis - BSV no.51
In June 2018, the BEA published the report on the accident involving the Cosmos Chronos 16 microlight registered 25-OB, which occurred on 13 July 2009 at Montbéliard (25). The instructor was seriously injured and the student died.
Full report at:
https://www.bea.aero/fileadmin/documents/docspa/2009/25-b090713/pdf/25-b090713.pdf
The investigators found two fatigue fractures of the seat frame, as well as ovalisation of the bores in the base tube and the triangular mast attachments; the bolts were not found. It is possible that, under the thrust at take-off or in the initial climb, the mast came away from the base tube and that excessive loads broke the seat frame, already weakened by fatigue. The accident can thus be described as a chain of technical facts (ovalisation, fracture, etc.).
To explain how the mast came away from the base tube, let us try to map out the cause-and-effect links in a diagram.
It thus appears that the technical factor (TECH) is explained by a combination of elements linked to the human operator (HF). The same diagram could be drawn for the failure of the seat frame.
This demonstration illustrates a universally accepted principle in aviation: 100% of the factors explaining accidents are human factors. They often belong to the pilot and sometimes to the designer, the activity organiser, and so on. Accident prevention therefore depends solely on taking these human factors into account.
Bernard Boudou
Flight Safety Analyst
Editorial
Hot-weather operations
It is summer and this year it is particularly hot. If we suffer from excessive temperatures in our daily lives, they also have significant consequences for our flights and our microlights. Once again, we can use the I.P.A.D.E. model to manage the various threats we will face on these increasingly frequent heatwave days.
Training Corner
It was a great party, but...
The 23th Tour ULM has just finished, it was a great party, but… 128 machines, 4 classes, 270 people, a logistics convoy masterfully led, marvellous scenery, dream weather, simply a success. We all came home, all of us, and that is what matters most.
Safety in Figures
The table below summarises the accident statistics recorded from 1st January to 30 July 2018, ranking casualties by severity and distinguishing purely material-damage accidents. The second table shows accidents involving microlights registered in France that took place abroad with foreign crews.
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