Inlet Engine Fairings / Shapes / Swirl Mark

Dear All,

Alot of people in the field are always asking why the engine inlet fairings differ from engine to another?? Some of them are cones another are half ball??

What does the Swirl White Solid Line Means??

I would like to clarify this issue in a very simple way giving an example of some engine types.

On CFM56-5A/5B/5C, the engine inlet fairing looks like a cone. This cone has a specific sliding angle which is called (Anti Ice Algebric Angle). According to the studies done by the designers, they have noticed that at this specific angle of cone slide the ice will not accumulate or build up on the engine inlet cone which in some cases it may become dangerous on engine operation.

On V2500, although it is a cone, but the cone slide doesn't have Anti Ice Algebric Angle as it is more acute angle. Instead of that angle, the cone head is made of small piece made from rubber. This peice will keep vibrating while engine is running preventing engine inlet ice accumulation or build up mechanically. (REALLY SMART DESIGNERS).

On CF6-8, the engine inlet fairing isn't completely a cone. It is half ball shape and as we know on this shape, it is almost impossible to be the perfect shape for ice accumulation or build up. Now most of the Engine Inlet Fairings have swirl solid white line. This line will become like EAGLE EYE shape when the engine starts to run. This shape can be distiguished clearly by the birds. The EAGLE EYE shape will make birds frightened from coming near the engine while running and this will prevent bird ingestion or what we call (ENGINE BIRD STRIKE).

Please note that in the near future, you will find alot of photos and schematics explaining most of common questions generated by different people in the field and from passengers.

B.Regards
Ayman Shak'ah
Licensed Aircraft Maint. Engineer