Cessna SkyHawk SP 172S NAV III 2005 Pilot Operating Handbook page 236

SECTION 7
AIRPLANE AND SYSTEMS DESCRIPTION
ENGINE
(Continued)
RPM (TACHOMETER)
CESSNA
MODEL 172S NAV III
Engine speed (RPM) is shown by the tachometer indicator found on
all EIS pages. The tachometer indicator uses a circular scale with
moving pointer and a digital value. The pointer moves through a
range from 0 to 3000 RPM. The numerical RPM value is displayed
in increments of 10 RPM in white numerals below the pointer.
The normal engine speed operating limit (top of green arc) changes
with altitude. For standard-day conditions, between sea level and
5000
ft.,
2500 RPM is the upper limit of the normal operating range.
From 5000 ft. to 10,000 ft., 2600 RPM is the top of the normal
range. And above 10,000 ft., 2700 RPM is the upper limit of the
normal operating range. When engine speed is 2780 RPM or more,
the pointer, digital value, and label (RPM) turn red to show engine
speed is more than the limit. The digital value and label (RPM) will
flash. The engine speed (tachometer) is displayed in the same
configuration and location on the LEAN and SYSTEM pages. If
engine speed becomes 2780 RPM or more while on the LEAN or
SYSTEM page, the display will return to the ENGINE page.
A speed sensor, mounted on the engine tachometer drive accessory
pad, provides a digital signal to the GEA-71 Engine and Airframe
Unit which processes and outputs the RPM data to the EIS. A red
X through the RPM indicator shows the indicating system is
inoperative.
FUELFLOW
Fuel flow is displayed on the ENGINE page by the FFLOW GPH
horizontal indicator. The indicator range is from 0 to 20 GPH with 2
GPH graduations. A green arc from 0 to 12 GPH is the normal
operating range. A white pointer indicates the measured fuel flow.
A digital value for FFLOW GPH is included on both the EIS LEAN
and SYSTEM pages.
(Continued Next Page)
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