Reversing the course of "billed charges" is much more difficult than just avoiding them in the first place. My specialized technical consulting service focuses on the entire process utilizing:
1. Upfront negotiation before a repair or overhaul shop is awarded work
2. Proper troubleshooting to insure proper direction
3. Verification of discrepancies found
4. A fair cost analysis process
5. Accountability requiring success of completed work
During a pre-purchase inspection of an aircraft the prospective buyer should consider taking a very good look inside the engines. Any hidden damage will at some future date cost tens of thousands of dollars to correct. I inspect internally with a high quality video borescope and hand you digital photos for use in negotiating a better purchase price / and for forecasting future maintenance costs.
I articulate the small 4 mm camera around to see turbine blade condition and make approximate component life projections. Very useful considering a set of blades can cost $100K or more depending on engine model. (See bottom left photo.)
I also tend to find combustion liner burning and cracking as seen in this photo to the right. Depending on the engine time in service it may allow for some discounting in aircraft purchase price.
Fuel nozzle condition can also be seen as in the bottom right photo.
Engine compressor for possible damage and/or corrosion on other components can also be detected.
I will assist you in understanding and making your best case during this borescope inspection.
Please review my website. I look forward to answering any questions you may have so as to better serve you and help your maintenance resources net you greater results.