Expert: Marc Ebelini - 2/8/2008

Question
QUESTION: Can i get a short note on "reliability of aircraft engines and power plant"

ANSWER: On what extent do you want reliability information. Statistical information is kept by the FAA regarding on such matters. That is how they determine the TBO on different engines. Some engines have low TBO's based on the reliability factors. Adherence to maintenance schedules also play an important part on reliability. Does not matter whether it is jet or piston. New jet engines typically get higher TBO's than piston engines. Just today that question arose about reliability. Any powerplant known for it's reputation can be compromised by poor operating practices. For example the previous pilot exceeded the red line and did not report it. Then no stress tests are scheduled putting further operation at risk.
If you need further information it must be more specific.


---------- FOLLOW-UP ----------

QUESTION: what are the reliability factors and means at which aircraft engines and power plants can be maintened.

Answer
Without getting into any exact details about maintenance this should satisfy your short note request. Adhering to not only the manufactures recommendations there are also requirements to be met set forth by the FAA. For example,100 hour compression test or during annual inspections. Providing to proper amount and quality of the fuel and oils. Other inspections may be set forth like hot box and blade inspections on jets and valve clearance and other test for piston. One of the best methods is oil analysis. The laboratories know what the normal amount of wear is to be expected so that when one type of material becomes excessive relative to the parameters set forth the owners are advised of the condition. True story to illustrate my point. This Cessna 210 engine was not listed by serial number of having a soft cam shaft. However the owner was given warnings on two schedule oil test that there was an excessive amount of one of the metals in the engine. The engine lost power during a flight and not only landed safely but on an airfield with an engine shop. What they found was a soft cam shaft. The lab had included that the excessive metal could be a cam shaft but the owner dismissed that because his engine was not on the list from the FAA. Here is where the history of an engine is important. It had been overhauled an the shop used one of those recalled shafts. Reliability is only as good as the competence of the people working on the equipment. Need I say more?