
A large helicopter crashed last month near Norfolk, Va., and not only wasn’t the National Transportation Safety Board mobilized, but it probably even had advance warning. The planned wreck was part of a continuing series of rotorcraft crash tests sponsored by NASA in partnership with the FAA, the U.S. Navy and the U.S. Army, dating back to 2009. Those first two tests involved a lightweight ex-Army OH-6 (MD500), which was hoisted 35 feet in the air on cables at the agency’s Langley Research Center and let go. Think trapeze with an abrupt stop at the bottom of the arc. This initial test investigated the efficacy of a deployable energy absorbing (DEA) composite honeycomb “cushion” installed underneath the fuselage, and whether it would protect the cabin occupants in the event of crash. According to the report following the test, “the probability of injury in the pilot, copilot or rear passenger is below the low category, indicating a very low probability of risk.”
As for the helicopter itself, the cushion did protect it enough to allow it to be recycled the following year in another drop, this time with no protection. The flight path angle (33 degrees) and speed (33 mph) were the same as in the first drop, approximating a “relatively severe but survivable helicopter crash.” Packed with instrumentation and sensors as well as four crash test dummies (including one equipped with fake internal organs), the helicopter swung forward and smacked into the concrete with enough force to crush the skids, crack the windshield open and inflict potentially paralyzing injuries to the passengers, according to the instrumentation. This time the helicopter suffered enough damage to be excused from further abuse.