Did You Know: What Is The Spiral On The Aircraft Engine?


If you are travelling frequently or if you are interested in aircraft design, you may have noticed a spiral painted on the center of the aircraft engine. Have you ever wondered what is it for? Although this spiral looks like a decorative aircraft detail, it is more than just a design element. This spiral was painted as an important safety measure.

Ground Crew warning

The primary function of the spiral is to warn the ground crew working around the aircraft that the engine is on and to ensure nobody comes up too close to the running engine. Working near a running jet engine is extraordinarily dangerous and it is important that the ground crew members can identify a running engine and stay away from it.

How is the spiral working? If the engine is off, you can clearly see the spiral in the center. When the engine is running, you will see a white almost transparent blur or a hypnotizing swirl, depending on the rotation speed of the engine.

You may know that aircraft engines make noise when they are on. And now you may be wondering how ground crew can’t hear the deafening roar of a running jet engine? Firstly, the ground crew wear the hearing protection. Secondly, there may be several aircraft engines running at the same time, thus it is not always obvious which engine is running and which isn’t.

Protection from birds

Another reason for the painted spiral is to prevent the aircraft engine from the bird strike. The idea is the same as warning the ground crew – spinning spiral notifies of the danger.

There are several studies and publications on the impact of the spiral on reducing the bird crash number, thus the opinion on this issue differs. While proponents state that the rotating spiral repels the birds from flying into the running engine, opponents claim that the engine is rotating at a high speed and it is too fast for the birds to see the spiral. The discussions continue and the theory of the spiral is still not proven scientifically. However, birds avoid planes in general before they see the spirals on the engines due to the noise produced by engines and aircraft aerodynamic.

Although, the spiral may not affect birds, it has a huge impact on the ground handling crew work environment. Even the smallest detail in aviation is designed for the safety.






We use cookies and other similar technologies to help provide our Services, to advertise to you and to analyse how you use our Services and whether advertisements are being viewed. We also allow third parties to use tracking technologies for similar purposes. If you are using our Services via a browser you can restrict, block or remove cookies through your web browser settings. To learn more, Read More.

Necessary Cookies

Always enabled

These cookies are necessary for our website to function properly and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms or where they’re essential to provide you with a service you have requested. You cannot opt-out of these cookies. You can set your browser to block or alert you about these cookies, but if you do, some parts of the site will not then work. These cookies do not store any personally identifiable information.
Performance Cookies
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site, which helps us optimize your experience. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not be able to use your data in this way.
Targeting Cookies
These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising.
Save & Accept