Heathrow take-offs aborted after eight planes infested by insects, report shows

A Wall Mason wasp collected from a pitot probe on an Airbus 319 aircraf

An investigation has found that eight commercial flights with abandoned take-offs from Heathrow were caused by insect infestations.

Wasp and bee nests were found on the planes, the Air Accidents Investigation Branch (AAIB) said in a report.

British Airways crews on board two of the planes were forced to abort take-offs while speeding down runways because the nests were blocking speed measuring probes, leading to inaccurate speed readings on cockpit displays.

The blockages caused inaccurate speed readings Credit: AAIB/PA

Unreliable speed indication is a "serious hazard", investigators warned.

The infestations affected six British Airways planes and one Virgin Atlantic jet over a three-week period between June 9 and July 1.

A wasp was also spotted inside a probe on another British Airways plane.

A larger number of insects could emerge in the spring of 2022, based on the activity last year, said the AAIB and warned the risk of more probe blockages "could be significant".

Safety action has been taken by the Civil Aviation Authority, Heathrow Airport and affected airlines to reduce the risk of the problem reoccurring.

This includes issuing alerts to aviation firms, introducing additional inspections of probes, enhanced use of probe covers, and increased surveillance of environmental risks.

An insect entering a probe on a British Airways plane Credit: AAIB/PA

A British Airways spokesman said: "Safety is our highest priority and in each case the flights returned safely to stand.

"Our highly skilled pilots are trained to safely perform this type of standard procedure and practise them regularly."

Virgin Atlantic did not respond to a request for a comment.

The issue of insects blocking pitot probes is not new, but it is "unusual for such a spate of events to occur in such a short timeframe, the AAIB said.

Nest material and larvae collected from a pitot probe on an Airbus A330 Credit: AAIB/PA

A "temporary surge” in cases was due to a series of factors related to the reduction in air travel caused by the coronavirus pandemic, the report said.

Aircraft remaining on the ground for longer periods between flights created an "attractive opportunity" for insects as pitot probes are an "ideal construction site for nests", it said.

The AAIB said the incidents should act as a reminder that "the environmental response to changes in human behaviour can be unpredictable and have unforeseen consequences".