A closer look is needed at the dangerous anomalies observed in the classic, very common phenomenon of attention focus. It has been shown to possess many different characteristics but can be summed up as mentally concentrating on a situation but focusing attention on a particular aspect of the situation. The phenomenon of attention focus can take different forms. In the cases studied in the research, it either occurs before the trigger event or is caused by it. In all cases, the stress of the situation transforms it into a tunnelling effect, generating unsuitable reactions to situations encountered. Where pilots need a proper awareness of the real situation, it instead obscures the picture, distorting any assessment of how it will evolve. It is therefore highly dangerous and can happen at any time and in any situation. Appendix C gives some details of case studies into this attention focusing.