AMT Study Guide 2026

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.

Propeller de-ice systems work by cyclically heating the elements in the boots. This heating is not meant to evaporate all the ice, but rather to melt the thin layer adhering to the blade surface. Once this bond is broken, the centrifugal force of the rotating propeller slings the remaining ice off the blades.

14 CFR 43.9 explicitly requires that a maintenance record entry contain: a description of the work, the date of completion, and if the work was performed satisfactorily, the signature, certificate number, and kind of certificate held by the person approving the work for return to service. Total time-in-service is required for inspection entries under 43.11, not general maintenance entries under 43.9.

Feathering involves turning the propeller blades to be nearly parallel with the direction of flight. This presents the smallest profile to the oncoming air, which significantly reduces the drag produced by the windmilling propeller of a failed engine, improving the aircraft's single-engine performance.

The diffuser is a divergent duct located between the compressor section and the combustion section. Its purpose is to slow down the high-velocity air from the compressor and increase its pressure before it enters the combustion chambers, ensuring stable combustion.