During maintenance on his Piper Aerostar 602P, an aircraft owner—who we’ll call Paul—was told that eight windows showed signs of crazing and would need to be replaced immediately, at a cost exceeding $30,000. Unsure whether such an expensive repair was truly necessary, Paul turned to SavvyMx for guidance.
The shop’s position was straightforward: the manufacturer’s maintenance manual states that if crazing is found, the window must be replaced. That language is a classic “when-to” statement—it establishes the condition under which the manufacturer says replacement is required.
But here’s where the nuance matters.
Under FAR Part 91, aircraft owners are not legally required to comply with manufacturer “when-to” statements. Those are recommendations unless incorporated into an Airworthiness Limitation or AD. Owners operating under Part 91 may exercise judgment, in consultation with their IA, about whether a condition truly renders the aircraft unairworthy.
Savvy CEO, Mike Busch, helped clarify this critical distinction. A “when-to” statement tells you when the manufacturer recommends replacement. A “how-to” statement, by contrast, lays out the required procedure if you decide to perform the replacement. While Part 91 operators may evaluate whether to comply with a “when-to” recommendation, they must follow the manual’s “how-to” instructions exactly if the work is performed.
In this case, there was no objective measurement—no minimum thickness, no defined severity limit—just the presence of crazing. That left the airworthiness determination in the hands of the IA, whose responsibility is to decide whether thecondition makes the aircraft unsafe for flight.
Armed with this understanding—and with Savvy on his side—Paul chose not to replace the windows at that time. The aircraft returned to service, and Paul avoided a $30,000 expense.
Afterward, he summed it up simply:
“Having Savvy on my side saved me a lot of money.”
This is exactly where SavvyMx adds value: helping owners understand the difference between regulatory requirements and manufacturer recommendations—and ensuring maintenance decisions are informed, not automatic.
