Forget snakes on a plane: invasive wasps have been nesting in valuable pieces of airplane equipment, posing “a serious threat to aviation safety,” according to one Australian airport.
The Brisbane Airport, which handles tens of millions of passengers each year, reported 26 wasp-related airline issues between November 2013 and April 2019. For three years beginning in 2016, the airport funded an experimental monitoring program to inform mitigation efforts and identify the single or multiple culprit species.
Researchers in charge of the program identified the interferer as the non-native keyhole wasp, Pachodynerus nasidens. This finding and others were published on Wednesday in the journal PLOS One.
“It's a rather hidden and insidious threat,” said Alan House, the first author of the paper and an ecologist at Eco Logical Australia, the environmental consulting firm hired by the airport. “The keyhole wasp is not an aggressive species at all. Murder wasps, European wasps, or paper wasps can get really cross if you mess around with them, but these guys don’t do that—they’re just trying to make airplanes crash.”
Keyhole wasps do that, the researchers found, by building nests in pitot probes, which are hollow, tube-shaped devices that sit on the exterior of the plane and measure airspeed. Not only do the probes serve a vital purpose for air navigation, House said, but each one also costs between $5,800 and $7,300 to replace.
House and his co-authors published a risk assessment of keyhole wasps nesting in pitot probes in an airline trade publication earlier this year, calling the issue a “significant and potentially catastrophic threat” in Australia because of previous disasters.
A 1996 flight from the Dominican Republic crash-landed and killed all passengers and crew members after taking off, for example, likely because a small insect had blocked a pitot probe and caused pilots to misjudge the speed of the aircraft.
Brisbane Airport administrators were prompted to record detailed data about wasp-related incidents following an episode in 2013 in which two of a plane’s pitot probes measured repeated discrepancies in airspeed, causing a mayday situation. Later investigation found evidence of a mud wasp’s nest in one of the probes.
For the PLOS One study, the researchers attached 3D-printed plastic replicas of different types of probes to steel sheets that they then affixed in various locations around the airport. They observed 93 instances of keyhole wasps blocking the probes, the first occurring just two weeks into the three-year study period.
Anecdotally, Brisbane Airport ground crew had noticed wasps start to build nests in a matter of minutes after planes landed, House said.
“Sometimes a plane will arrive at a gate, and almost immediately they'll see a wasp buzzing around the nose of the airplane. The wasp already knows that that's a good spot to look—it's quite spooky in a way,” he said.
Any step of the nesting process could be enough to throw off a probe’s measurements. Keyhole wasps will first stuff the nest with prey in the form of a paralyzed caterpillar; that alone will block the probe inconspicuously, unlike the mud and sand of a complete nest, House added.
One solution, which some airlines already employ in a local capacity, is covering the probes upon landing. Unfortunately, House said, there have been documented cases of crews forgetting to uncover the probes, which leads to the same dangerous result as wasp blockages.
Due to threats to the continent’s native biodiversity, Australia has notoriously strict policies regarding invasive species. But according to House, the keyhole wasp—which is native to South America and was first found in Australia in 2010—has not received much attention because it is not an agricultural pest or a nuisance to humans.
Though the researchers only focused on Brisbane Airport, the wasps could easily travel up the eastern coast of Australia and cause similar problems at over a dozen airports on the continent, House said. Airports in the wasps’ natural range should also be aware of this danger and take preventative measures to cover probes and exterminate wasps, he added.
The Asian giant hornet, nicknamed the “murder hornet,” is another invasive wasp species that has attracted media attention for its destruction of honeybee hives. Keyhole wasps aren’t as well-known, though they too pose significant risks, House said.
“The murder hornet's name is a bit sexier, it's a big thing, and it behaves very aggressively. But a single [keyhole] wasp putting a caterpillar in a pitot probe could bring down an aircraft of 350 people.”