The pilot of the Piper Pawnee took off from Baxter Springs, Kan., then noticed a decrease in the engine’s oil pressure, followed by a loss of engine power. The pilot was slightly injured in the forced landing.
An examination of the engine revealed that the No. 2 piston had failed. In addition, each of the spark plugs had two washers installed, instead of one, and the oil filter contained many metal particles.
Investigators determined the two washers likely altered the detonation characteristics of the pistons, causing them to overheat. As the No. 2 piston degraded, metal particles collected in the oil filter.
Maintenance records indicate that the engine was overdue for a recommended oil change. The mechanic who performed the last annual inspection was not aware that additional spark plug washers had been installed on the engine.
The NTSB determined the probable cause as the loss of engine power due to improper maintenance by an unknown individual that led to the degradation and deterioration of the No. 2 piston, which was undetected because of overdue maintenance.
NTSB Identification: CEN13LA280
This May 2013 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
That TCM Tierra engine must be closely monitored. It runs very fast (bottom end) and puts an abundance of power for such a low displacement engine. I’ve seen plug gaskets stick on all brands of aircraft engines and I have seen engines missing spark plugs gaskets when brought in for service.
Potential detonation may very well was the cause of this and aggravated by the extended oil change period. I have found that oil is cheaper than aircraft parts to change, too.
I dont think NTSB was the topic of discussion….Lack of proper maintenance was…it appears it pays to know who is doing maintenance on your aircraft and if not keep it on the ground…. it is going to comedown once you take it up and could kill you and or others if you dont
I was taught “Situational Awareness” pertains to ALL aspects of aviation………of course i could be wrong………..just a thought
The military and others who want to fly and operate safely seriously, consider the attributes of Oil Spectrometric Analysis, oil filter condition, and other methods recommended by Savvy Aviator/Mike Busch. The operator and Mech should consider their future actions. The Mech should brief his workers on these potential issues.
Really? NTSB claimed that the piston wear was not detected because of an overdue oil change? There’s no requirement for doing an oil analysis, so how is it “expected” (apparently), that an oil change would catch the degraded piston and washers on the plugs?
The NTSB probable cause does not mention oil analysis. It says the accident was caused by “The loss of engine power due to improper maintenance by an unknown individual that led to the degradation and deterioration of the No. 2 piston, which was undetected because of overdue maintenance.”… In other words, lousy maintenance procedures by the owner/company and lousy record keeping as well.
The FAA investigator on scene report is in the Docket located on the NTSB website. The investigator reported: “I removed the oil filter and found a large amount of aluminum particles in the oil; so much the oil was of a metallic tint. The oil filter was cut open and a great amount of metal was found in the filter, the oil drain plug was removed metal was found lodged in it.”
Timely maintenance by a competent and conscientious mechanic would have caught both problems. I’m glad the pilot survived without serious injury. The docket contains a photo of the wreckage. Only the cage was relatively intact. Everything else (wings, engine, fuselage, etc.) was bent, twisted, torn.