Andy asked why aircraft manufacturers can't put a screen or a grill in front of airplane engines so they won't suck in birds.

Michael sent me an answer that jibed with the experts' response. "There is no practical way to prevent a bird from entering an engine of a modern commercial airliner," said Matthew Perra, spokesman for engine-maker Pratt & Whitney.

A 12-pound bird hitting an aircraft traveling at 150 mph has the force of a 1,000-pound weight dropped 10 feet. A screen that could stop such a force would be prohibitively heavy and would disrupt air flow to the engine, significantly reducing thrust, Perra said.

A Boeing spokeswoman said that if such a screen were knocked loose and entered the engine, it would cause more damage than a bird would.

The industry is developing more damage-tolerant engines and has raised standards for engines' ability to withstand bird strikes, in addition to trying to keep birds away from airplanes. The industry has formed Bird Strike Committee USA (birdstrike.org) to investigate and report on the issue.

Here's a new challenge:

In an era of belt-tightening, why is President Obama using expensive Montblanc pens to sign bills into law and then giving them away? - Donna

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