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How Cessna 172s Systems Work


Mike's Expertise on Cessna 172S Systems

Mike identified shortcomings in the Cessna 172 S model systems manual and shared his expertise as a technical writer and satellite engineer. He introduced CFI Bootcamp's 172s Systems Guide, aimed at providing a clear and comprehensive explanation of the aircraft's electrical system, which he believes is often misunderstood due to a lack of proper consideration of electricity.

Discussion about the airframe's design, the instrument panel, and the significance of various aspects such as oil pressure, voltage, and fuel levels. He emphasized the importance of understanding the system's functioning and not relying solely on hope.

Safe Flying and Flight Instructor Experiences

Conversation regarding the importance of having reliable equipment for safe flying, especially in challenging conditions. The recommendation to use systems like Foreflight with Sentry, which provide comprehensive instruments for safe operation, and highlighted the significance of regular maintenance checks, especially for older aircraft. He also corrected previous misconceptions regarding the use of decongestants while flying and provided detailed explanations about the fuel systems between Cessnas. Mike shared his experiences as a flight instructor, both close calls and humorous instances, emphasizing the importance of following instructions and not emulating his methods.

Technical Discussion and Team Updates

We addressed several technical topics related to electrical systems. Mike explained the concepts of voltage, current, and resistance using a water analogy and clarified the difference between a series circuit and a parallel circuit. He emphasized the importance of interlock switches in specific scenarios and touched on the use of switches in combination with circuits. The discussion also included an update on the resolution of previous test issues and the introduction of two new team members.

Aircraft Electrical System Overview

Thorough explanation of the workings of an aircraft's electrical system, using the concept of a 'contactor' or 'relay' as a large switch to control the flow of current. He detailed the role of the master switch, a smaller switch, and a coil in ensuring safe and efficient current distribution to various components like the starter motor and main bus. Mike also shared a personal anecdote about his experience with the Ohio State versus Michigan University rivalry while studying at Ohio State University. Finally, he provided a technical overview of a Cessna 172's electrical system, highlighting the function of the various components, including the starter switch, contactor relay, and ammeter. The discussion continued with electrical systems of an aircraft, focusing on the role of the battery, alternator, and voltmeter. He used a diagram to illustrate the direction of current flow and the potential for charging the battery. Mike emphasized the importance of the master switch in activating the starter and indicated that the alternator, which produces 60 amps, cannot overcharge the battery. He also explained that the voltage on the bus would indicate the battery's charge level, and a bi-directional ammeter would show the current flow. Finally, he advised that the emergency checklist could be used to understand the system's behavior.

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Cessna 172S Systems
Cessna 172S Systems

Our Systems Guide is the Perfect Companion to Understanding the Model S and it's Internal Systems.

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