A Cessna 182 owner's question about logbook entry obligations following an unsolicited compression test and borescope inspection touches on one of the more commonly misunderstood areas of Part 91 recordkeeping under 14 CFR Part 43. The crux of the situation is that a field A&P, engaged only to investigate a suspected induction leak via propane test, independently elected to perform differential compression tests and borescope inspection — neither of which was authorized by the owner — and subsequently issued a top overhaul recommendation along with a logbook sticker documenting the compression numbers. No maintenance, alteration, repair, or preventive maintenance was performed on the aircraft. The owner's compression numbers, while all above the FAA's 65/80 minimum threshold, represented a significant outlier from established trend data, raising reasonable questions about test methodology, particularly engine temperature at the time of testing.
Under 14 CFR Part 43, recordkeeping obligations attach to the performance of maintenance, preventive maintenance, rebuilding, and alteration — not to inspections or evaluations conducted in isolation. Section 43.9 requires the person who performs such work to make a logbook entry; Section 43.11 governs entries specifically for approved inspections such as annual and 100-hour inspections. A standalone compression test and borescope review, conducted outside the scope of an annual or progressive inspection, does not constitute maintenance and does not trigger a mandatory logbook entry. Because the A&P made no repairs or adjustments and held no inspection authority over this aircraft's annual cycle, the owner bears no legal obligation under Part 43 to insert the A&P's sticker into the aircraft logbook. The recommendation for a top overhaul is a clinical opinion, not a required airworthiness action.
The practical implications extend beyond the regulatory question. Aircraft logbooks are legal documents that travel with the aircraft and directly affect resale value and insurability. An unsolicited entry recommending a top overhaul — based on compression numbers that Savvy Aviation and the owner's primary A&P both find inconsistent with the borescope findings — could create significant downstream complications. Any prospective buyer, insurance underwriter, or lending institution reviewing the logbook would encounter what appears to be a documented maintenance concern, even though the aircraft was annualed three months prior with all compressions above service limits. The temperature of the engine at the time of testing is a critical variable: a cold or partially warmed engine will produce artificially depressed compression readings that can falsely suggest cylinder wear, and without knowing the engine's thermal state during this test, the numbers carry reduced diagnostic validity.
The broader context for Part 91 operators is that logbook integrity is a two-way concern. Owners and operators have an affirmative interest in ensuring that only accurate, properly authorized entries appear in aircraft records. The scenario described — where an A&P performs work beyond the stated scope without owner authorization and then attempts to document that work in the aircraft's permanent record — highlights the importance of clearly defining scope of work before any technician touches an aircraft. For operators running Part 91K fractional or Part 135 operations, where maintenance tracking and MEL compliance depend on clean, accurate logbook histories, unauthorized or misleading entries can have cascading effects on airworthiness determinations and operator certificate compliance. Getting a second and third opinion from qualified maintenance providers, as this owner did through Savvy and his primary shop, reflects exactly the kind of due diligence that protects both the aircraft's airworthiness record and the operator's legal standing.