Friday 21 June 2024

What does it mean when your plane has a bird strike?

A bird strike is being blamed after flames were seen coming out the back of a Boeing 737's engine that made an emergency landing in Invercargill this week.

Virgin Australia flight VA148 departed Queenstown Airport (ZQN/NZQN) just before 6pm, bound for Melbourne (MEL/YMML), before turning around and landing safely in Invercargill (IVC/NZNV) an hour later.

The plane "experienced an issue just after take-off and has been diverted to Invercargill Airport", Queenstown Airport said in a statement. It was confirmed the cause was a bird strike.

Bird strikes have affected planes since they were first invented. And despite technological advances helping to predict bird movements, it's likely to be an issue for a long time to come. Wildlife strike is the umbrella term, because while most cases involve birds, there have been cases of other animals, and even people, getting sucked into the running turbine engine of a plane.

The first reported bird strike is said to have occurred in 1905, when the Wright Flyer flown by Orville Wright struck a bird over an Ohio cornfield.

The most well-known case of a bird strike is that of US Airways Flight 1549 in 2009.
Shortly after pilot Chesley "Sully" Sullenberger took off from New York's LaGuardia Airport, two large geese flew into each of the plane's twin engines. Both engines stopped working, and the pilot had to choose between trying to reach an airport runway or attempting a water landing.

Sullenberger aimed for the Hudson River, and everyone aboard survived.
This was a very rare and unfortunate case of both engines being out of action.

It's unusual for planes to lose even one engine while flying, and they're designed to be able to rely on just one. They won't have the maximum thrust power for take-off, but they can continue to fly and land safely, Professor Doug Drury, head of aviation at CQ University Australia, says.

Bird strikes above 500 feet (150 m) altitude are around 7 times more common at night than during the day.

Anything ingested by a turbine engine "becomes shrapnel", Drury says. The damage caused will depend on the size and number of the birds involved. There will be a loud noise and possibly flames, he says. The pilot will shut down the engine and divert to another airport close by.

In theory, it could continue flying to its destination. "But pilots don't want to take risks if we don't have to," Drury says.

Airlines can also get fined for putting passengers in jeopardy if they continue to fly.

"Pilots train extensively for single-engine operations. The Virgin crew did exactly what they were trained to do." It's important to keep in mind, despite these types of events, that "flying is still the safest mode of transport", he says.

How common is it?
Bird strike rates at Australian airports is about seven in 10,000 aircraft movements, according to research. About 90 percent of cases occur at low altitudes at airports, during take-off or landing, according to the group.

Worldwide, it causes more than $1.7 billion in aircraft damage annually.

Queenstown Airport says bird strikes are a known risk to aviation around the world. But the Civil Aviation Authority has recorded the incident rate for bird strikes at the airport as "low".

"The primary species of concern at Queenstown are oyster catchers and plovers, along with smaller birds such as finches, starlings, and sparrows."

While the "vast majority" of strikes around the world are by birds, there have been cases in New Zealand of planes colliding with large rabbits, according to the NZAWHG.

Average bird strike rates (number of strikes per 10,000 aircraft movements) for different countries.

Country         Bird Strike Rate         Period Considered 
Australia              7.76                             2008–2017 
Canada               4.51                             2008–2018 
France                 3.95                             2004–2013
Germany             4.42                             2010–2018 
UK                       7.46                             2012–2016 
USA                     5.83                             2009–2018  

Nevertheless, while collisions between birds and aircraft usually result in lethal consequences for the bird, aircraft damage is rare. Two to eight percent of all recorded bird strikes result in actual aircraft damage in civil aviation. Regarding operational impacts, between six and seven percent of all reports indicate a negative operational effect on the flight. 

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