The AAIB investigation identified the cause of the pitot system blockage events to be the nesting activity of certain species of wasps and bees within pitot probes. The report addresses the likely reasons as to why there was a concentration of such events over a relatively short period of time.
Although Heathrow Airport and the surrounding area was the focus for these occurrences, detailed information on the environmental factors is provided for the operators of airfields at other locations to take into consideration.
Safety action has been taken by the CAA and those airline operators affected to reduce the risk of reoccurrence by introducing additional inspections and changes to the use of pitot covers. In addition, the airport operator is updating its environmental hazard management plan to take into account the findings of this investigation.