According to NASA, the way to make a helicopter safer is to crash it – under strict guidance, of course. In order to test the effectiveness of a new "airbag" system - which is actually an expandable honeycomb cushion called a deployable energy absorber - NASA aeronautics researchers at Langley loaded four crash test dummies into a small chopper and, well, dropped it.

The helicopter fell from a height of 35ft (10.7m) and to ensure it reacted like it would in a real accident, pyrotechnics were used to remove the attached cables just before it hit terra firma.

Aside from damage to the landing skids the damage was minimal with the cushion protecting the cockpit. The crash test dummies emerged shaken but uninjured, one of which was fitted with a special torso with simulated internal organs.

In all, instruments aboard the crash chopper collected 160 channels of data. Researchers are yet to fully analyze the test results before they categorically can say whether the deployable energy absorber worked as designed.

To test the airbags, a 240ft tall structure once used to teach astronauts how to land on the moon was used in conjunction with a MD-500 helicopter donated by the Army.

"I'd like to think the research we're doing is going to end up in airframes and will potentially save lives," said Karen Jackson, an aerospace engineer who oversaw the test at NASA's Langley Research Center.

According to the National Transportation Safety Board, more than 200 people are injured in helicopter accidents in the United States each year, in part because helicopters fly in riskier conditions than most other aircraft. A helicopter passenger death in Australia just days ago highlights the dangers of this type of flight, often caused because these craft fly close to the ground, not far from power lines and other obstacles, and often are used for emergencies, including search and rescue and medical evacuations.

Created by engineer Sotiris Kellas at Langley, the airbag system is made of Kevlar and has a unique flexible hinge design that allows the honeycomb to be packaged and remain flat until needed.

The test conditions imitated what would be a relatively severe helicopter crash. The flight path angle was about 33° and the combined forward and vertical speeds were 33mph (53kph).

"We got data to validate our integrated computer models that predict how all parts of the helicopter and the occupants react in a crash. Plus the torso model test dummy will help us assess internal injuries to occupants during a helicopter crash," she said.


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