The 'spirals' in the center of the reactors? Pretty (and mesmerizing) but they are not decorative. Their vital function

Depending on their design, they have been nicknamed by aviation enthusiasts as 'the comma', 'the vortex', 'the spiral', 'the apostrophe' and even 'the typhoon'. But everyone can call them whatever they like, depending on what they see in them. Wanting to use a somewhat more technical term, however, they can be referred to as 'Spinner spirals', where the latter is That cone or that half sphere that is in the center of the blades that are at the front of the aircraft engine passengers.

The blades are those 'blades' that by their swirling capture air, compressing it, and then push it into the turbine. They radiate out in clusters from a cone- or half-sphere-shaped structure usually black or otherwise dark in color that, almost always, is adorned with 'drawings' precisely of various shapes, made in white.

When the motor is activated and the compressor blades begin to turn, the blank drawing (rotating in turn) takes on the appearance of a spiral, apostrophe or stylized typhoon. Its function, of course, is anything but decorative. In fact, it can be highly vital in the sense that. can save lives: those of those working on the apron just a few meters from the planes.

The ramp staff, as it is called in the jargon, moves in an extremely noisy environment and because of that, as you may notice from the terminal windows or looking out the porthole as you sit in the plane before departure, often wears insulating headphones, which reduce the effects of that noise. But which inevitably impair auditory perception. Which can be Very dangerous at the stage of engine start-up.

It sometimes happens that pilots, in order to save time and aiming for an on-time start, Begin thruster ignition procedures while still pushing the aircraft backward By the so-called pushback 'little tractor'. To wit, when the plane is still only a few meters away from the gate and the people working around it. It is often the case that there are several planes nearby with engines on or running, and it may happen that, due to the effect of headphones, an attendant does not realize that the plane next to him is proceeding to start the reactors. 

The 'spinner spirals' function, under these circumstances, as a A visual system to alert ramp attendants that an engine is on and running, causing them to maintain an adequate safety distance, considering that the engine of a small jet in operation is sufficient to suck in and kill a man more than three meters away and larger engines create even larger 'danger zones'.

Not all passenger aircraft are, however, equipped with these 'spirals.' They do not, for example, have them on all regional jets of the Embraer family (ERJ 170, 175, 190 and 195), such as those that, in Italy, fly for Air Dolomiti.

And even some Boeing 757, 787 and 747-8s have left the plants without those safety devices.

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