Lincoln Rgnl/Karl Harder Field Airport
Aircraft Accident/Incident Report

Lincoln, California 95648
Thursday, September 4, 2014 20:10 PDT

On September 4, 2014, at 2010 Pacific daylight time, a Eurocopter AS 350 B3, N217HP, landed hard during a practice autorotation at Lincoln Regional Airport/Karl Harder Field, Lincoln, California. The helicopter was registered to, and operated by, the California Highway Patrol as a public-use, training flight. The commercial pilot and flight instructor (CFI) were not injured. The helicopter sustained substantial damage during the accident sequence. The local flight departed Auburn Municipal Airport, Auburn, California, about 1950. Visual meteorological conditions prevailed, and no flight plan had been filed. The purpose of the flight was to provide recurrent emergency procedure and night vision goggle (NVG) training for the pilot, who was positioned in the right seat. Prior to departure, the crew discussed the plans for the flight, and the pilot performed a preflight inspection. The decision was made to perform a full landing at Lincoln, followed by a practice autorotation with power recovery, and then once ambient light had diminished, transition into NVG training. Because they departed during daylight the pilot turned off the NVG unit's battery pack, and moved the goggles to the up position on his helmet. Both occupants recounted the circumstances of the accident, stating that once the startup and departure checklists were complete, the CFI performed a throttle check in preparation for the emergency maneuvers. With all systems nominal, they departed and the pilot performed an uneventful landing on runway 15 at Lincoln. They then departed to practice the autorotation on the same runway. The CFI asked the pilot to make his primary goal attaining the appropriate rotor and air speeds rather than focusing on a specific landing spot. Once they were both ready, the CFI rolled the left-side engine throttle to the idle (MIN) position to initiate the maneuver. The pilot lowered the collective and the helicopter descended; once they reached an altitude of about 50 feet above ground level, the pilot began to initiate the flare, with the CFI countering by rolling the throttle to the flight (VOL) position. They heard the engine respond along with an accompanying yaw motion, and the CFI announced "power recovery." The pilot stated that he held the helicopter in the flare, and the rotor speed started to increase, so he pulled up lightly on the collective control to prevent an overspeed condition. The helicopter then "ballooned" slightly, and he lowered the collective to recover. The forward speed decayed, and he moved the helicopter forward in anticipation of the hover. As he started to raise the collective control, the low rotor speed horn sounded and the helicopter began to rapidly descend. He pulled up the collective in an effort to arrest the descent, and the helicopter hit the ground hard. His NVG goggles flipped down over his eyes, and because the battery pack was not turned on, his forward vision became effectively blocked. He then perceived forward and nose-low motion as the CFI took control of the helicopter. He felt the cyclic pull full aft, and the helicopter came to rest. Once on the ground the CFI pushed the collective control to the full down position, and confirmed the throttle was in the flight detent. The rotor speed indicator reported a speed below the green arc at 360 to 370 rpm, and the amber GOV and TWST GRP caution lights were still illuminated. He cycled the throttle to idle, and then back to flight, but the rotor speed would not exceed 370 rpm. He repeated the operation with no increase in rotor speed, and then reached over to unlock the flight gate on the right-side throttle control. The engine responded, and the rotor speed increased to 390 rpm, but the caution lights were still illuminated; he then twisted the throttle back out of the gate and into the flight position. He reached up to the overhead engine start panel and cycled the engine operation switch back to idle and then flight; the engine responded appropriately, and the caution lights finally extinguished. He then asked the pilot to shut down the engine. Subsequent examination revealed that the tailboom had bent downwards at its intersection with the aft bulkhead, just below the engine exhaust outlet. The aft bulkhead sustained wrinkling damage, and both aft landing skid support tubes were bent.

Not Yet Reported