CEN15LA383

The commercial pilot/owner noted that, during previous flights in the agricultural application airplane, he had heard a "wheezing" sound coming from the engine. During a conversation with a mechanic about the issue, the mechanic stated that the abnormal engine sound could have been due to an issue with an engine valve. Although an annual inspection was completed after the pilot first noted the issue, no maintenance was conducted to resolve the issue. Despite this, the pilot chose to continue flying the airplane. The pilot reported that, while en route to the destination field during the accident flight, he heard a noise come from the engine, followed by a partial loss of power as the engine shuddered. He subsequently made a forced landing to a wheat field. A postaccident engine examination revealed that the right magneto was not functioning, and two of the cylinders did not pass compression checks. The loss of engine power is consistent with a failed magneto and two cylinders with low compression.

On August 20, 2015, about 1900 central daylight time, a Piper PA-25 Pawnee airplane, N4652Y, experienced a loss of engine power and made a forced landing in a field near Harvey, North Dakota. The commercial pilot was not injured and the airplane sustained substantial damage. The airplane was registered to a private individual and operated by Jake's Flying Service of Harvey, North Dakota, under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed. The local flight originated from a private strip near Harvey, North Dakota about 1855. The pilot reported that while en route to the destination field, he heard noise from the engine and noticed a loss of power as the engine shuddered. He made a forced landing to a wheat field. During the landing roll the left main landing gear collapsed and the airplane skidded to a stop. The left wing skin was wrinkled. The pilot reported that prior to the accident flight he noticed a "wheezing" sound coming from the engine. He recalled that in a previous conversation with a mechanic, the mechanic stated that the "wheezing" could be a valve issue. The pilot reported that an annual inspection was completed on May 23, 2015, but no maintenance inspection was completed after the "wheezing" sound was noticed. A local mechanic conducted a postaccident engine examination which revealed two significant findings. The right magneto was "dead" and would not produce a spark at any of the terminals. The No. 2 and No. 6 cylinders did not pass the compression checks. The examination did not reveal any other anomalies.