Ever since the ditching of U.S. Air Flight 1549 in the Hudson River in 2009, questions have been raised about the use of screens over jet engines to help protect them from bird ingestions. While the possibility has been considered, there are a number of reasons why it is not a workable solution.
The modern day turbofan jet engine creates thrust two ways. First, a percentage of air flowing through the engine is used to turn a turbofan that creates thrust much like the propeller of a propeller-driven plane. Secondly, air exiting the engine exits at a much higher speed than the air entering the engine. A screen in the front of the engine would disrupt this airflow.
Jet engines use engine bleed air to heat the engine nacelle. A screen mesh in front of the engine would be extremely susceptible to ice buildup.
A screen capable of preventing a bird from being ingested into an engine would have to be extremely rigid and require strong reinforcements, adding weight and negatively affecting aerodynamics.
A screen in front of a jet engine would not only disrupt airflow, but it would create turbulence that would have a negative impact on engine performance.
Jet engines are designed to continue operating even after a bird ingestion, as long as the bird is of a reasonable size and there aren't multiple birds ingested. The cost of overcoming the many negatives associated with a screen outweigh any benefit that might be realized.
