AMT Study Guide 2026

Cracks parallel to the grain in a wood propeller are cause for rejection because they can rapidly propagate and lead to structural failure.

A dual ignition system uses two separate magnetos, harnesses, and spark plugs for each cylinder. This provides redundancy, meaning if one entire system fails, the engine can still operate on the other. Additionally, having two spark plugs ignites the fuel-air mixture from two points, leading to a faster, more complete combustion process, which improves engine performance and power output.

Safety wiring is a mechanical locking device used to secure fasteners, such as nuts, bolts, and turnbuckles, in critical aircraft applications. It ensures that these components remain tight and do not vibrate loose during operation, thereby preventing potential system failures and maintaining structural integrity. This simple yet effective method is a cornerstone of aviation safety.

Blade angle is measured and specified at 75% of the propeller radius because this station best represents the average aerodynamic performance of the blade.

Under Part 91.409, large aircraft not operated under a Part 121 or 135 program must undergo an annual inspection and, if used for hire, a 100-hour inspection.

Basic empty weight includes the airframe, engines, fixed equipment, unusable fuel, and full oil, but NOT usable fuel which is part of useful load.