Birds are bad

Bird strikes can be really bad. Take the recent TUI swan strike out of London Gatwick. The double strike occurred at around 1000 feet, and resulted in significant damage to the windscreen and front of the aircraft.

Someone much better at maths and physics than me can maybe calculate the impact force of an 11kg swan and a closing speed of about 200 knots – it’s a lot.

In 2022, an A320 suffered an explosive decompression at around 13,000 feet after migrating Ross’ geese impacted it.

And how about US airways flight 1549.

Or Jeju flight 2216…

How many are we talking?

The UK CAA reckon around 1500 bird strikes happen every year, the majority involving gulls and pigeons. The FAA stats are more alarming (not surprising given the size of the USA in all fairness).They reported just under 20,000 (19,603) wildlife strikes in 2023.

That’s 54 a day on average. Here are some figures if you like ‘em:62% happen during the day, 61% on landing, 70% between the ground and around 500 feet and 30% are waterfowl, 22% gulls. These are smaller, but can still cause significant damage.

While the ‘Miracle on the Hudson’ accident involved some Canada geese – a flock of them – and those brutes can weigh up to nearly 6.5kg, the Jeju crash likely involved Baikal Teal. These are a relatively small duck that weighs around 400g, or just under a 1lb.

Here’s the thing, it doesn’t take much when you’re talking high speeds, to do some serious damage to an aircraft if a critical or particularly sensitive area is impacted. Engines can fail, flight controls can be blocked, pitot tubes damaged, windscreens rendered un-seeable through, bulkheads can be burst… and all of this comes with a level of startle which makes it very hard for the pilots to react quickly and well.

Here’s the problem

Well, two problems really.

Firstly, pilots are warned about birds via NOTAMs, and sometimes on the ATIS too. These tend to say things like:

BIRD CONCENTRATION PILOTS TO EXER CTN

Or maybe:

BIRD CONCENTRATION ON MANEUVERING AREA AND VICINITY OF AD. TYPE OF BIRDS – OPEN-BILLED STORK, PAINTED STORK, GREY HERON, PURPLE HERON, CATTLE EGRET, LITTLE EGRET, BARN OWL, LESSER WHISTLING DUCK, BLACK-WINGED STILT, ORIENTAL PRATINCOLE, COMMON MOORHEN, PIGEON BIRD WEIGHT – FM 20 UP TO 3500 GRAMS MAX FLOCK SIZE- 200 BIRDS.

Which, hopefully, you can understand is a problem because even the most avid bird spotter is unlikely to have time to identify which specific bird is flying right at them as they hurtle down the approach (let alone really have time to avoid it). And what exactly does “exercise caution” really mean? I’m not sure I know many pilots who are particularly reckless when it comes to birds, and yet we keep hitting them.

The second issue is our impact (and I mean aviation in general) on the environment is not entirely known, but is most likely increasing. A possible cause of the ‘Emirates 777 vs an entire flock of flamingoes’ came down to the pink and leggedy things flying an “unusual trajectory”, widely blamed on new power lines.

A study of over a thousand birds around 6 airports in South America showed that a lot had been habituated to the noise levels. So at best, basically don’t care much anymore (certainly aren’t scared by big noisy jets), but also more worryingly the noise levels could be masking their usual “watch out” calls. This could be preventing flocks from warning one another, reducing their ability to perceive predators (I think we can refer to a jet engine as a predator in this scenario) and with it their ability to assess risk.

More mitigations are needed

Which is why further mitigations are needed.

South Korea, for example, following the Jeju accident, has mandated all their main airports must install bird detection cameras and thermal imaging radar by the end of 2026. The plan is these will detect even more distant birds and will send info to ATC on bird size, movement paths and other useful trends so they can relay this to crew and/or send something out to ensure the detected avians don’t impact on aircraft flight paths.

Currently only 4 of their airports have these systems in place. In 2019, a report suggested “over 40” airports worldwide were using bird deterrent laser. In 2021, the rate of strikes in Europe apparently increased by 205% on the same quarter from 2020

In addition, things like rubbish dumps, which attract birds, will be prohibited within certain distances of airport and major flight paths.

What about aircraft?

Aircraft are tested.

New EASA guidelines (check out the possible new guidance here) plan to make it so an aircraft will need to be able to withstand a bird strike to the engine, and after a defined recovery period, still be able to maintain at least 75% of its capacity for medium and small birds, and 50% for bigger ones. This is based off one bird heading straight at the core, and a second at the most exposed part of the first stage rotor blades.

What can we – pilots – do too though?

Well, as much as we laugh at endless bird NOTAMs, they are one of the primary ways of building awareness of where birds might be, and having an awareness of high risk places, and some awareness of migratory patterns for larger birds is important in helping avoid them/plan for them.

Awareness of the potential impacts and actions to handle them low level should be considered, with some level of contingency plan or at least a “What if…?” Idea in place for things like an engine failure on approach, dual engine out low level etc. In fact, this is really important. I should have put this as the Number 1 thing to be done.

Pilots should report sightings, even if away from the immediate flight path, particularly when it’s a larger flock. Likewise, if a strike on takeoff or landing is suspected, report it to ensure the runway is cleared, and the aircraft can be properly checked at the end of the flight.

Report strikes through here so that it can continued to be monitored, and keep up to date with strike data on site like this so you are aware of higher risk airports.

I said birds are bad…

And of course that isn’t entirely fair. It is the combination of big airplanes and birds that is bad, and that isn’t really the birds’ fault. In fact, birds have had a lot of very positive impact on aviation too. After all, they are our primary inspiration.

To acknowledge that and celebrate it, here’s a link to my truly ridiculous “Absurd Bird Book”.