Details of the bizarre series of events last night prompted air force chiefs to declare it abnormal behaviour by a pilot.

Any abnormal behaviour, deviations from flight paths, radio silence or distress signals are picked up instantaneously.

Reports said that he had been displaying abnormal behaviour and the company had asked his family to come and support him.

When things go wrong, people are more likely to attribute the negative outcome on any abnormal behaviour leading up to the mishap.

These signs include opisthotonus, hyperaesthesia, abnormal behaviour, ataxia, head pressing, blindness, proprioceptive deficits, coma and seizures.