There are a few operating costs thread on the forum, I liked the title on this one.
My rule of thumb, applies to SEP only, is £1 per HP per hour – this is for 100 hours per annum. Includes reserves and contingencies, and hangarage.
That will be in the right ballpark for a company maintained plane, but I’d say there are many factors which affect this a lot more than the engine size. Whether you can maintain with a freelance engineer or have to use a company, and the degree of neglect in years past, can affect the ground costs by a factor of two.
