On December 11, 2004, a Robinson R22B (registration N145RJ) was involved in an aviation accident near Los Angeles, CA. Investigators recorded the probable cause as: The activation of the low main rotor rpm warning system for undetermined reasons. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter experienced a low rotor warning over downtown Los Angeles, leading to an autorotation. The aircraft overshot a rooftop helipad, and its main rotor blades struck window washing equipment. Post-incident inspection found no mechanical abnormalities.
Incident Details
While flying over downtown Los Angeles at approximately 1,200 feet mean sea level, the pilot observed the low rotor warning light illuminate. Shortly thereafter, the low rotor warning horn activated.
Sequence of Events
The pilot entered an autorotation and attempted to land on a helipad located atop a 56-story office building. During the landing phase, the helicopter overshot the landing pad. The main rotor blades then contacted window washing equipment on the building. The helicopter missed the helipad and came to rest below the helipad on the roof.
Examination
An examination of the aircraft's systems and the engine was conducted. The examination failed to disclose any abnormality.