How a 4-Pound Bird Wrecks a 75-Ton Plane

As we've all learned by now, a fairly small bird can cause devastating damage to a jetliner. While it's not official, it appears that US AIrways Flight 1549 crash landed on the Hudson River on January 15 after one or both engines sucked in birds and conked out, leaving the jet without power.

[See how Capt. Sullenberger really saved Flight 1549.]

It might seem starting that a small element of nature can neutralize million-dollar modern technology, yet in the aviation business, the risk of bird strikes has been well understood nearly as long as planes have been flying. That's why engine manufacturers conduct routine tests to assure their engines can withstand foreign objects. In one typical test, a bird carcass weighing about four pounds is fired into the engine.

Part of the goal is to build engines durable enough to keep operating even if they ingest small objects. But above a certain size, that's impossible. So manufacturers also design engines to assure that any parts that break off stay contained inside the engine. Otherwise, they'd become shrapnel that could easily rip through the soft aluminum skin of the jet's fuselage, wrecking its airworthiness and possibly harming passengers. As long as the fuselage is intact, planes are designed so they can keep flying after losing an engine.

Here's a video that's been circulating in the aviation community. It shows a bird-strike test of a Rolls-Royce Trent 900 engine, which powers the Airbus A380 jumbojet. (Please click here for an important update on the video below.) That's bigger than the A320 that crashed in the Hudson, which was equipped with different engines. Still, this test demonstrates why it would be rather startling to be on a plane when one of the engines sucked in a bird.