Robinson R44 N25VH accident near Silver Spring, Pennsylvania

Probable cause

The student pilot's inability to fully control the helicopter, during cruise and the resultant off-field hard landing.

NTSB analysis

The student helicopter pilot was at the end of the cruise portion of a solo cross-country flight. When she was about to begin her descent to the destination airport, she noticed that the vertical speed indicator was indicating a descent of approximately 1,000 feet per minute and that the airspeed had increased about 10 knots. The pilot "raised the collective" control in an effort to reduce or stop the descent, but the helicopter did not respond as she expected and the descent continued. She then determined that she would not be able to reach the airport, and selected a field suitable for a landing. The helicopter landed hard in the field, and sustained substantial damage to the skids and portions of the engine mount and fuselage. On-scene examination did not reveal any preimpact failures or anomalies and postaccident testing, including runs at the engine manufacturer's factory, indicated that the engine performed normally and was capable of developing its rated power. The helicopter was equipped with hydraulically boosted main rotor flight controls which were to be used for all phases of flight. The pilot's control for activating or deactivating the hydraulic system was a 1/4 inch unguarded toggle switch located on the pilot’s cyclic control stick. The accident helicopter was not equipped with any visual or audio annunciations to alert the pilot that the hydraulic system had either failed or was selected off in flight, and no such option was available from the manufacturer. According to the helicopter manufacturer's pilot operating handbook, "Hydraulic system failure is indicated by heavy or stiff cyclic and collective controls," and that in the event that the hydraulic system failed or was turned off, "control will be normal except for the increase in stick forces." Although some control symptoms experienced by the pilot were consistent with an inoperative hydraulic system, some were not, and no physical evidence of an inoperative hydraulic system was noted.

Text from the NTSB. Open the NTSB docket for ERA09LA410 for the full record.