Handle With Care

Any time repairs or other work is performed on an aircraft, it’s a good idea to conduct a post-maintenance test flight to ensure everything is working as it should. There’s even a regulation, FAR 91.407, covering such flights and the “operational check of the maintenance performed or alteration made.” In many ways, someone conducting such a flight is a test pilot, determining whether the work performed was completed properly and the aircraft performs as intended. During such flights, we generally plan to conduct a functional check of any and all systems potentially affected by the work performed and return. This, of course, presumes we don’t find a problem with the work performed. If we do find a problem during our post-maintenance check flight, an obvious response is to get the aircraft back on the ground expeditiously and resolve the issue. Depending on the problem, we may or may not be in a hurry: To us, an engine oil leak would mean hurry up and land, while a flight-control system issue might encourage us to take things easier and handle the aircraft gently.

Joseph E. (Jeb) Burnside

Friday, January 18, 2013 at 12:00 AM ET

Verified

Key Takeaways:

Post-maintenance test flights are crucial for ensuring aircraft systems function correctly after repairs, but they carry inherent risks of discovering in-flight issues like system failures.
A military jet trainer crashed during a post-maintenance test flight after experiencing a loss of hydraulic pressure, which impacted secondary flight controls during the landing approach.
The NTSB determined the probable cause was the pilot/mechanic's improper decision to continue a tight-turning, high-banked landing pattern despite the hydraulic loss, leading to an accelerated maneuver stall.
The incident underscores the importance of a prudent pilot response to in-flight system failures, advocating for abandoning aggressive maneuvers and properly configuring the aircraft for a controlled return rather than attempting a risky recovery.

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During such flights, we generally plan to conduct a functional check of any and all systems potentially affected by the work performed and return. This, of course, presumes we don’t find a problem with the work performed. If we do find a problem during our post-maintenance check flight, an obvious response is to get the aircraft back on the ground expeditiously and resolve the issue. Depending on the problem, we may or may not be in a hurry: To us, an engine oil leak would mean hurry up and land, while a flight-control system issue might encourage us to take things easier and handle the aircraft gently.