There are numerous examples of birds colliding with planes in incidents that prove deadly for human passengers, hence why airports use various methods to deter fowl. Now, several airports are working to deter a smaller, airborne pest that also proves a deadly threat: wasps. As the Wall Street Journal reports, the keyhole wasp, a species native to Central and South America, sees planes' Pitot tubes—"a crucial instrument on the fuselage that tells pilots how fast they are flying"—as a perfect place to build its mud nest. They can block a tube in as little as 20 minutes, with deadly results. The crashing of Birgenair Flight 301, which went down off the Dominican Republic in 1996, killing all 189 people on board, is believed to have been partly caused by a wasp nest.
In 2013, an Etihad Airways flight "declared a mayday" for the same reason, per the Journal. It was forced to return to Australia's Brisbane Airport, which has seen "more than two dozen wasp-related safety incidents in recent years." To prevent future threats, authorities there spray insecticide on the airfield to kill caterpillars that serve as a key food source for the wasp. Adult wasps seal caterpillars in nests to provide food for hatched larvae. Officials say targeting the caterpillars has reduced the number of wasp nests by 64%, per the Brisbane Times. The strategy, introduced after much study, is being closely watched outside of Australia, including in the UK, where a similar wasp was blamed for tube blockages at London's Heathrow Airport last year, resulting in two aborted takeoffs, per the BBC.
Heathrow's wasp prevention efforts currently include insect monitoring and Pitot tube covers, which are also required by Hawaiian Airlines after the discovery of keyhole wasps in Hawaii. But covering the tubes "adds yet another task for busy ground crews," per the Journal. Several planes have had to return to Brisbane Airport above maximum landing weight, with full fuel tanks, with covers still attached, per the Times. "With an invasive species, with human lives on the line, and such a specialized problem, you really are looking at mostly the only option being some sort of insecticide," Jonathan Larson, a pest-management expert at the University of Kentucky, tells the Journal. Authorities in Brisbane say the plant-based insecticide has "low toxicity to birds, fish, and bees," per the Journal. (Read more wasps stories.)