Aircraft engines are likely to face new safety rules in the UK to counter the growing threat of collision with heavyweight geese, following research from the UK Civil Aviation Authority (CAA).
The research was carried out by the British Trust for Ornithology (BTO) and indicates that populations of large Canada and greylag geese have increased dramatically over the last 10 years in the UK.
The CAA is concerned that a large flock of geese could cause a plane to crash. “We are proposing changes to engine standards to make them resistant to larger birds,” says a spokesman for the CAA. “At the moment standards only cover smaller birds.”
The study found that the number of Canada geese in the UK has risen by roughly two-thirds to 90,000 in the last decade. Greylag geese number around 60,000 and this figure is also rising sharply. Canada geese can weigh as much as 4.5 kilograms and greylag can weigh up to 3.0 kg. The birds travel in large flocks of over 100 and can cause serious damage on impact with a commercial airplane.
“Geese are a menace,” says Bill Gunston, editor of Jane’s Aero Engines, a specialist industry publication. “A couple of geese in each engine at take off would be bad news.”
A flock of geese caused a military airplane to crash in the north of England in 2000 and geese have caused commercial airplane accidents in the US.
Airplane jet engines are currently built to withstand an impact with a bird weighing 3.6 kg but this figure is likely to be increased as part of new safety standards, says the CAA spokesman.
But Gunston says that most large aircraft engines can already withstand an impact of up to 8.0 kg. He also believes it may be difficult to redesign smaller engines to be more robust. The main defence against a bird strike lies in the strength of an engine’s fan and the sharpness of the fan’s blades – sharp blades quickly cut any bird hazard down to size.
The recent explosion in geese numbers in Britain can be put down to increased breeding for shooting as well as poor management of geese in public parks, says Graham Austin of the BTO. Instead of trying to control numbers, geese are often relocated, seeding a new population, he says.
Austin adds that reducing existing populations by culling birds would be too controversial: “Its pretty much something we’re going to have to live with.”
As well as raising engine safety standards, the CAA may require airports to control nearby bird habitats. This could include filling in water repositories.