DFW05LA147

Following takeoff and after initiating a left turn to return to the field being sprayed, the 19,000 hour pilot reduced propeller RPM and the 2-bladed propeller "went to the full coarse setting and lost drive." During the forced landing the airplane struck a power line and subsequently impacted terrain. Examination of the propeller governor by a repair facility revealed that the "propeller governor pilot valve had failed, causing an internal oil leak, which resulted in the failure of the propeller governor. "

On June 4, 2005, at 1440 central daylight time, a single-engine Grumman G-164B agricultural aircraft, N6832K, was substantially damaged during a forced landing following a loss of propeller drive during cruise flight near Lake Charles, Louisiana. The commercial pilot, sole occupant of the airplane, was not injured. The airplane was owned and operated by O'Brien Flying Service, Inc., of Iowa, Louisiana. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 137 aerial application flight. The flight originated from one of the operator's remote field strips near Iowa, Louisiana, at about 1400.

The pilot reported to the operator that following takeoff, after initiating a left turn to return to the field being sprayed, the pilot reduced propeller RPM to a climb power setting when the pitch on the two bladed Hamilton Standard model 12D40-6101-12 propeller "went to the full coarse setting and lost drive."

The 19,000-hour pilot initiated a forced landing to a clearing. During the forced landing the airplane struck a power line, before impacting a rice field.

The operator reported that the 600-horsepower Pratt & Whitney R-1340-AN-1 radial engine had accumulated a total of 483 hours since its last overhaul, and the propeller had accumulated a total of 541 hours since its last overhaul. The last annual inspection was completed on January 5, 2005, approxiamately 366 hours prior to the accident.

Oil was present in the crankcase, and no evidence of metal was found in suspension or in the oil filter. The propeller governor, a Hamilton Standard model 1M12G, serial number 121470, had accumulated a total of 753.91 hours since its last overhaul. The propeller governor was removed for further examination by Aircraft Accessories of Oklahoma Inc., of Tulsa, Oklahoma.

In a telephone interview with a representative of the investigator-in-charge, a representative of Aircraft Accessories of Oklahoma stated, that the "propeller governor pilot valve had failed, causing an internal oil leak, which resulted in the failure of the propeller governor. "

The left lower wing, left main landing gear assembly, and the vertical stabilizer sustained structural damage. There was no fire.