Cessna 172S Center Panel
The Alternate Static source control can be pulled when a problem is suspected with the man static source. Use of the alternate static will alter the indications of the static instruments; the extent to which the indications will change can be found in the POH.
Elevator Trim Control
Moving the elevator trim wheel UP will increase the airplane's tendency to lower the nose, and vice versa. Ensure that the trim is set to the proper Takeoff setting prior to departure. as per the check list.
The fuel selector can allow the engine to draw fuel from each individual fuel tank, or from both tanks simultaneously. The POH generally recommends taking off and landing with the fuel selector in the BOTH position.
Fuel Shut Off Valve
The fuel shut off valve can be pulled in order to stop the flow of fuel.
The hand microphone is installed and ready for use in the event of a headset, microphone or audio panel failure. For example, if the pilot's headset mic stops working, he or she can still communicate with ATC by speaking into the standby microphone.
Rheostats to control the brightness of various interior lighting equipment are installed.