An AAIB report has revealed that insects were behind pitot probe blockages that caused rejected take-offs at Heathrow last summer.

Published on January 27, the results of the Air Accidents Investigation Branch (AAIB) investigation identified the cause of the pitot system blockage events to be the nesting activity 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 – several aircraft suffered abnormal pitot/static system events between June 9 and July 19, 2021, two of them resulting in rejected take-offs.

Although London/ Heathrow Airport and the surrounding area was the focus for these occurrences, detailed information on the environmental factors is also provided for the operators of airfields at other locations.

Safety action has been taken by the Civil Aviation Authority and those airline operators affected, to reduce the risk of reoccurrence. This includes 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.

The full report is available from the AAIB.