cessna-172-training-supplement

SECTION 2
Aircraft Systems
Late Model (R&S)
System descriptions are given first for Late Model aircraft, and then differences
only for Early Models.
Engine
The 172 R and S models are equipped with a Lycoming, 4-cylinder, normallyaspirated,
fuel-injected, 360 cubic inch, horizontally-opposed, air-cooled,
direct-drive IO-360-L2A engine. This engine is rated at 180 HP at 2700 RPM as
factory-delivered on S-models and as upgraded on R-models. (See note on page
2 regarding engine modifications.) Ignition is provided by 2 magnetos on the
back of the engine which provide power to 8 spark plugs (2 per cylinder, for
redundancy and more complete combustion). The engine has an 8-quart oil
sump. ATP's minimum oil quantity for takeoff is 6.5 quarts.
Propeller
The engine drives a McCauley, 76 inch, two-blade, all-metal, fixed-pitch propeller.
Vacuum System
On aircraft with conventional flight instruments, two engine-driven vacuum
pumps are located on the back of the engine, providing vacuum to the attitude
and heading gyros. These have a normal operating range of 4.5-5.5 inches of
mercury. Failure of a vacuum pump is indicated by an annunciator panel light.
In most circumstances, failure of one pump alone will not cause the loss of any
instruments, because the remaining pump should handle the entire vacuum
demand.
On aircraft with the G1000 glass cockpit, a single engine-driven vacuum pump
provides vacuum to the standby attitude indicator. The normal operating range
is 4.5-5.5 inches of mercury. Failure of this pump is indicated by a GYRO flag on
the attitude indicator and an amber LOW VACUUM annunciation on the PFD.
Aircraft Systems • 3