Wasps: one other drawback for aviation

Brisbane, Australia (CNN) – A tiny insect that has evaded Australia’s strict biosecurity controls is multiplying and threatening flight safety at Brisbane Airport.

The keyhole wasp, native to Central and South America and the Caribbean, first caused problems at the airport in 2013 when it forced an Etihad Airways A330 bound for Singapore to return minutes on the flight.

Once on the ground, maintenance workers found that the pilot’s pitot tube – the hollow instrument on the outside of the aircraft that measures airspeed – was almost completely blocked by mud, according to a report by the Australian Transport Safety Bureau.

Pitot tubes are the perfect cavity for wasps to build a high-speed nest – the Etihad plane was on the tarmac for just two hours before the aborted flight.

“We have individual reports from the Brisbane ground crew that a plane may have landed at the gate and within two or three minutes a wasp will fly around the plane’s nose and take a look at the probe,” said Alan House, an ecologist by Eco Logical Australia.

A keyhole wasp sits on top of a 3D printed De Havilland Dash-8 pitot probe.

HOUSE ET AL (2020) PLOS ONE

House worked with experts from Brisbane Airport, Australian airline Qantas and environmental consultancy Ecosure to produce one of the world’s first studies on the impact of wasps on pitot tubes. On behalf of Brisbane Airport Corporation, it was published this week in the open access magazine PLOS ONE.

Researchers say that without proper management, the wasps run the risk of traveling to other Australian airports – and even to nearby countries with the right semi-tropical conditions for them to thrive.

“When we did some background research, we found that not only was this an inconvenience, but that you just had to clean up these things and get rid of the wasps; it could actually lead to serious accidents,” House said.

An important tool

Pitot tubes are attached to the front of aircraft and do the important job of sending information back to the cockpit about how fast air is flowing through them. This indicates how fast the plane is flying – too slow and there is a risk of stalling, too fast and there may be other ways to malfunction.

If the pitot tubes fail, the A330 automatically switches to manual mode, forcing the pilots to take control. That’s what happened to the Etihad flight, and why the pilots ultimately returned.

There were no major incidents at Brisbane Airport due to the wasps, but accidents elsewhere have been linked to the insect.

According to researchers, airplane pitot tubes, which measure airspeed, are ideal places for wasps to build nests.

According to researchers, airplane pitot tubes, which measure airspeed, are ideal places for wasps to build nests.

JOKER / Hady Khandani / Wollsteinbild via Getty Images

For example, Birgenair Flight 301 crashed off the coast of the Dominican Republic in February 1996, killing 189 passengers and crew. The accident report stated that the “likely cause” of the blockage of the pitot tube was “mud and / or debris from a small insect” that entered while the aircraft was on the ground.

CASA advised airlines to cover up pitot tubes while waiting at Brisbane Airport. However, this is not mandatory, which is why blockages still appear. According to the Brisbane Airport study, a total of 26 incidents were reported between November 2013 and April 2019.

Smart wasps

The first keyhole wasps were spotted in the port of Brisbane in 2010, although they may have arrived as early as 2006, according to the study. It is unknown how they got to Australia – probably by ship, House said.

They are believed to have been at Brisbane Airport since 2012 and appear not to have spread to any other Australian city, despite being spotted at Emerald Airport, a small regional hub more than half a mile away, according to CASA.

For the study, researchers used 3D printers to print replica pitot tube probes on Boeing 737 and 747, Airbus A330 and smaller Dash 8 airlines, commonly used by regional airlines. They were positioned at four locations around the airport and monitored for 39 months.

There have been 93 cases of completely blocked probes during that time, and almost all of them were built in the warmer months between November and May.

Most of the nests were near the airport’s lawn, according to study co-author Jackson Ring, wildlife management and planning coordinator at Brisbane Airport. The wasps collect caterpillars from the grass and push them into the pitot tubes as food for their offspring.

Wildlife managers are using targeted organic pesticides to kill the caterpillars, and they have so far managed to reduce wasp activity by 50% near the international and domestic terminals, Ring said.

“We are treating approximately 120 acres (1.2 square kilometers) of the airfield. This is a selective method of removing this food source and making areas where aircraft are parked and prone to wasp infestation undesirable for the keyhole wasp,” Ring said.

Introducing predators, such as birds, is not an option for obvious reasons. Before the wasps arrived, Ring spent most of his time deterring wildlife to avoid bird strikes and other dangerous animal-aircraft encounters.

Can They Be Eradicated?

The wasp is not classified as an agricultural pest and is not a vector of human diseases. Despite their unwanted visitor status, there is no official government plan to eradicate them, House said.

It is also a very resourceful creature and there is no shortage of breeding grounds.

“It can build its own nest if it wants, it can use other mud wasps’ old nests if it wants, and it can use every nook and cranny. There are many, many, many places like this all over the airport and everywhere , basically everywhere, “said House.

“They’re very determined. These guys just need to find a nesting site. Put a caterpillar in, lay an egg, seal it.”

An aerial view of Brisbane Airport.

An aerial view of Brisbane Airport.

Glenn Hunt / Getty Images

Like most airports around the world, traffic at Brisbane Airport fell significantly during the coronavirus pandemic. Since July, international flights to Australia have been capped by returning traveler limits and state borders have been closed to contain local outbreaks. The planes were parked for months with their pitot tubes covered to prevent infestation.

Traffic will pick up again on Tuesday, however, as internal border restrictions are lifted – meaning more planes will come and go – and give wasps more opportunities to cause problems.

Keyhole wasps are also found in the southern United States and a number of Pacific islands, including Hawaii, Polynesia, Micronesia, and Japan, according to the study.

The researchers work with airport operators in Papua New Guinea and Fiji, where incidents have also been reported. They also sent 3D printed tubes and components to Honolulu for similar studies.

According to House, the researchers did not want to create the impression that it is not safe to fly out of Brisbane. If anything, he said, it’s safer than it was a few years ago when they knew less about the insect.

The keyhole wasp may be small, he said, but its threat to aviation cannot be ignored.

“A lot of attention is being paid to other airport wildlife management issues around the world, particularly birds, particularly because they are clearly seen as a major threat to flying,” said House.

“Something like a wasp is seen as more of a low risk. The chances of something happening are pretty slim, but there is still a chance that it will happen.”

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