LAX06LA169

The engine lost partial power during takeoff and the airplane nosed over during a forced landing in a field. The pilot said that during the takeoff-initial climb, the engine experienced a partial loss of power and the airplane would not climb. The pilot made an attempt to jettison the pesticide load; however, the airplane impacted the ground before he could fully manipulate the dump controls and it came to rest inverted. A Federal Aviation Administration airworthiness inspector examined the engine, propeller, and propeller governor following the accident and no mechanical anomalies were noted. Due to damage sustained in the accident, control continuity between the cockpit control and propeller governor could not be confirmed.

On May 15, 2006, at 0612 Pacific daylight time, a Grumman G-164B, N8981H, lost partial power during takeoff and the airplane nosed over during a forced landing at a private agricultural airstrip in Tracy, California. Trinkle Agricultural Flying, Inc., owned and operated the airplane under the provisions of 14 CFR Part 137. The commercial pilot, the sole occupant, was not injured; the airplane sustained substantial damage. Visual meteorological conditions prevailed, and no flight plan had been filed for the local aerial application flight.

The National Transportation Safety Board investigator interviewed the pilot on May 15. The pilot prepared the airplane for the day's first flight, and the taxi and run-up were uneventful. As the airplane climbed through 200 feet, the propeller began shifting into low rpm; however, the manifold pressure appeared normal. The pilot made an unsuccessful attempt to unload the pesticide. A locking control was situated between the gate and the spray handle. For this specific aerial application, the pilot used the spray handle so the locking control was positioned over the gate. When he attempted to dump the load using the gate, he did not have time to remove the locking control from the gate prior to the ensuing forced landing. The airplane landed hard, ripped the engine from its mounts, and came to rest inverted.

In a written statement submitted on May 22, the pilot reported that during the initial climb, about 1 mile from the airstrip and approximately 150 feet above ground level (agl), he heard a sound change in the engine. He turned his attention to the manifold pressure gauge and noted that the manifold pressure was 2 inches higher than normal. The airplane then failed to climb and the pilot leveled the airplane. In order to prevent impact with high voltage transmission towers, the pilot initiated a 2- to 5-degree left bank. The airplane continued to lose altitude, and he increased the manifold pressure to 37 inches. The airplane would still not climb, and when it was 50 to 75 feet agl, the pilot attempted to dump the pesticide. Prior to release of the pesticide, the airplane impacted the ground.

The Oakland Federal Aviation Administration Flight Standards District Office accident coordinator performed an examination of the Pratt and Whitney R-1340 engine and Hamilton Standard propeller governor and propeller following the accident. All control linkages to the propeller governor were fractured during the impact sequence. An examination of the engine and its accessories did not reveal any mechanical malfunctions or evidence of power loss. A functional bench test of the propeller governor revealed no operational anomalies that would have precluded normal operation.