Aviation Accident Summaries

Aviation Accident Summary WPR09LA312

Lakeport, CA, USA

Aircraft #1

N515DG

Robinson Helicopter Company R44 II

Analysis

The certified flight instructor (CFI) and pilot undergoing instruction (PUI) were on a local instructional flight. The helicopter was fueled about 15 minutes prior and they were initiating a 180-degree autorotation with a power recovery. The helicopter entered into a glide and they made the turn onto the final segment. The CFI noticed that the oil and auxiliary fuel pump lights were on. The CFI then looked at the tachometer and attempted to increase the throttle. The power did not return and the CFI force-landed the helicopter. During the landing the main rotor blade impacted the tail boom. Post accident examination of the helicopter and test run of the engine revealed no operational anomalies.

Factual Information

On June 25, 2009, at 1500 Pacific daylight time, a Robinson R44 II, N515DG, landed hard during a forced landing approximately 7 miles west-northwest of Lakeport, California. Cutting Edge Helicopters was operating the helicopter under the provisions of 14 Code of Federal Regulations Part 91. The certified flight instructor (CFI) and private pilot undergoing instruction (PUI) were not injured. The helicopter was substantially damaged. Visual meteorological conditions prevailed and no flight plan was filed. The CFI reported that the helicopter had been fueled to capacity prior to takeoff. They were conducting a 180-degree autorotation with a power recovery. They entered the helicopter into a glide and as they made the turn, the CFI noticed that the oil and auxiliary fuel pump lights were on. The CFI then looked at the tachometer and attempted to increase the throttle. The power did not return so the CFI committed to a landing. During the landing, the main rotor blades impacted the tail boom. The helicopter and engine were examined following their recovery from the accident site. The spark plugs were removed and examined. Their condition was consistent with normal operation when compared to a Champion Check-A-Plug chart. With the engine still installed on the helicopter and using the original fuel onboard the helicopter, it was powered. The engine test ran and no pre-impact anomalies were identified. According to Robinson Helicopter Company (RHC) Safety Notice SN-38, Practice Autorotations Cause Many Training Accidents, “There have been instances where the engine has quit during practice autorotation. To avoid inadvertent engine stoppage, do not roll the throttle to full idle. Reduce throttle firmly for a small visible needle split, then hold throttle firmly to override governor. Recover immediately if engine is rough or engine RPM continues to drop.”

Probable Cause and Findings

A loss of engine power while maneuvering for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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