- How many hours do you plan to fly each year?
- How long do you plan to keep the airplane?
- Where do you live, and what is the local maintenance labor rate?
- Will your plane be used by a flying club or flight school?
- The first is a summary of parts costs and labor hours for scheduled and unscheduled maintenance. The default labor rate is $125/hour, and you can adjust it to your local rate. The parts costs and labor hours are what I've seen on my invoices using an experienced DASC. If you are using a newly-certified service center, you may incur additional hours due to the learning curve. It does not include shipping costs, shop supplies, disposal fees, and other items that typically appear on maintenance invoices. It's built around 2000 hours and includes a provision for the 6-year/2400 hour MT propeller overhaul.
- The following four spreadsheets show maintenance expenses over time for different scenarios. First is a 400-hour/year scenario. The second is a 400-hour/year scenario used by a flight school or club (leaseback). The big difference here is the need for a 100-hour inspection during the 100-hour oil change. These do not include a propeller overhaul. The final two show 200 hours per year and 133 hours per year. The critical insight here is how time-based maintenance, like annual inspections and transponder/pitot-static certification, increase the hourly MX rate. You'll need to budget more per hour the less you fly per year.
- At the bottom of each of these spreadsheets is a financial summary. The first line shows the MX expense for each year in the scenario. The second line shows the cumulative expense total. Following these are calculations of the MX expense per hour for each year individually and the running expense per hour. You'll likely get this answer when you ask an owner what their average maintenance expense per hour has been. The last three lines show what a "smooth" rate looks like, i.e., one which averages all scheduled MX expenses (including overhauls) and creates a reserve. It shows the balance accumulated to pay for the high expense service intervals at 600, 900, and 1800.
Similarly, this analysis doesn't estimate possible price increases in parts, labor, or shipping. Nor does it include any provision for maintenance expenses for future AD compliance or AOG situations. Therefore, consider this to be a reasonable estimate of minimum maintenance expense.
A fundamental assumption is that the owner will own and operate the plane at least through engine TBO at 1800 hours. It also assumes that the owner won't exercise their part 91 prerogative to defer this maintenance. Owners who sell their planes before TBO (or any other higher-cost maintenance interval) and are willing to accept a price reduction to allow for this will have a lower (cumulative) maintenance cost per hour. The buyer will have a correspondingly higher cost. As long as there are no misunderstandings and no surprises to either party, this can work out for everyone involved.
I welcome feedback on the spreadsheet to make it more accurate, comprehensive, and useable to prospective and new DA40NG owners in planning their maintenance expense budgets.
DA40NG MX Budgets-23May22.xlsx- (57.96 KiB) Downloaded 766 times
