The A5 is powered by the Rotax 912iS Sport (912iS 2) fuel injected 4-cylinder engine, rated at 100 hp (74.5 kW) at 5,800 RPM. The 912iS Sport (912iS 2) is based on the proven 912 ULS engine with significant upgrades to improve performance and reliability. It is equipped with an electric starter, dual-redundant ignition system, and a fully digital Engine Control Unit (ECU) that automatically adjusts fuel/air mixture throughout flight to maintain optimal performance, efficiency and low emissions, thereby reducing fuel consumption and overall operating costs. The ECU also obviates the need for a carburetor and associated cumbersome mixture controls in the cockpit, making operation of the engine fully automatic for the pilot and eliminating the threat of carburetor icing. The 912iS Sport (912iS 2) is both liquid- (cylinder heads) and air- (cylinders) cooled with a dry sump forced lubrication system and separate oil tank. It can run on either Aviation Gasoline (AVGAS), motor gasoline (MOGAS), or a combination of both.

Commanded throttle position is sensed and transmitted to the ECU as a pilot request for specific power output. This signal is then combined with environmental inputs to provide the commanded response. The interface is simple and seamless for the pilot, automating the process of adjusting fuel/air mixture and ensuring optimal performance. Move the throttle and the engine does the rest.

Engine power is displayed as RPM on the tachometer gauge on the right lower flight instrument cluster. Fuel flow is directly proportional to this RPM, although actual power output and useful thrust delivered is a function of both RPM and aircraft density altitude. Normal operating range is from 1,400 to 5,500 RPM with a redline of 5,800 RPM for no longer than 5 minutes.

The engine has 2 internal alternators, Alternator A: 14.2V/16A and Alternator B: 14.2V/30A. During engine start, the engine components are powered by the battery. Once the engine starts, alternator B runs the engine components until RPM threshold is reached (2400 RPM for 3 seconds). Once the threshold is reached, alternator A takes over the engine components, and alternator B powers the aircraft systems and charges the battery. If either alternator fails, the battery becomes the only power source for aircraft systems. If both alternators fail, the battery becomes the only power source for aircraft systems and engine components.

This section provides common maintenance tasks and information related to the engine. Tasks not provided here are not permitted and require the prior approval of ICON Aircraft and must be performed by current, Rotax and ICON-approved individuals or repair facilities.