Question for Paul McBride, the General Aviation News engines expert: Do you see elevated risk in flying a plane right after an engine overhaul? If so, what minimum amount of Since Major Overhaul (SMOH) hours would you like to see for optimum safety?
Ryan Purtell
Paul’s Answer: Ryan, you’ve asked an interesting question, one that I think has probably crossed the minds of many pilots.
Let me assure you that flying a plane following an engine overhaul is safe — providing that the overhaul was done in compliance with all the engine manufacturer’s recommendations and specifications, in addition to any FAA AD Notes that may apply to that specific engine.
This statement also applies to any factory engine.
The overhaul facility should make all available records of work completed, and parts used, which should be well documented and become a permanent part of the engine records.
The most important thing that needs to be complied with, for Lycoming engines, is the information set forth in Lycoming Service Instruction 1427C regarding Lycoming Reciprocating Engine Break-in and Oil Consumption. Compliance with this important publication should assure that the engine meets all of the requirements for return to service.
All of the aforementioned should provide you with confidence that the engine is safe to fly.
Infant mortality with engines and their installation is a real concern and should not be taken lightly. I have had my fair share of issues with planes that have newly installed engines. My personal experience is that the installation of a new engine is a larger portion of the risk factor. Engines are run in a test cell after overhaul to ensure proper function…this is the “unit test”. Once installed on the plane it is now ready for a “system test”. While the engine was tested on the ground in a test cell, there is no way to system test the plane without flying it. Employ high levels of threat and error management (TEM) in your approach.
I have had my Cessna 1960 Cessna 172 since 1975. The original Continental 0 300 is still in it. Has over 3600 hours
Just finished it’s 2nd overhaul.
Performs flawlessly, granted I do my own maintenance. The overhauls done by a “BY THE BOOK” shop in the Phoenix Valley. NEVER had any mechanical or electrical incident. Thus following the run in procedures all has been going excellent.
I have found, after flying for 60 years with no incidents of any kind, that “going by the book” and staying in the Envelope” has great results.
As my flight surgeon says ” keep doing what you are doing and you and your plane will fly to at least 100, I am over 83 years old now.
STAY SAFE AND LEGAL.
I take issue with the photo that accompanies this article. Of course, it is a “staged” photo, but it should show safe maintenance practices. Boot laces should be tied up, safety glasses should be worn, and torque wrenches should not be left on work platforms where they can get kicked and damaged. Let’s set a good example.
Also, when the editing was done to remove the aircraft registration, the fuel stain from the bottom of the wing should also have been removed.
Mine was majored at the local FBO. When they were done and I looked it over and recowled it, I took it x-country first flight across the Rockies.
Results may vary….lol
Factory overhauled or remanufactured engines do tend to provide a level of confidence not found with field overhauled “equivalents.” But regardless of the source, a measure of common sense should prevail. If you’re asking the question of Mr. McBride, perhaps you already own the answer.
Stick close to the airport for a while. Gain some confidence in the engine and the installation before launching out to parts unknown.
I wouldn’t call flying with a new engine ‘risky’, but any new piece of equipment has a possibility of what is known as an ‘infant failure’.
The first 100 hours of running a new engine has some probability of a part defect and failure. So, It is most prudent to fly withing gliding distance of an airport during the initial break in and first 100 hours.
Refer to ; https://www.blackstone-labs.com/critical-component-failures/
100 hours flying in the pattern?