Leaning Using Exhaust Gas Temperature - Cessna 172S NAV III Pilot Operating Handbook

8ECTION4
NORMALPROCEDURE8
CRUISE
(Continued)
CE88NA
MODEL 1728 NAV III
LEANING USING EXHAUST GAS TEMPERATURE
(EGT)
The cruise performance data in this handbook is based on the
recommended lean mixture setting determined from the maximum
l
or Peak Exhaust Gas Temperature (EGT) at power settings of 75%
Maximum Continuous Power (MCP) and less. The 1728 Nav III
provides EGT indications for all (4) engine cylinders. The ability to
monitor all cylinders is an aid in early identification and correction of
fuel injection system problems.
NOTE
All engine cylinders do not receive identical fuel/air
mixtures (due to unequal intake pipe lengths, uneven
intake air temperatures, fuel injection nozzle
tolerances etc.). However, all cylinder EGTs should
be within approximately 100°F of each other during
normal operations. An EGT difference greater than
100°F between cylinders indicates that fuel injection
system maintenance is necessary.
EGT is displayed on the EIS ENGINE and LEAN pages. The
ENGINE page has a horizontal scale with a temperature indicator
(inverted triangle) with a number representing the cylinder with the
highest EGT.
The EIS LEAN page provides vertical bar graph displays showing
EGT for all cylinders. The cylinder with the highest EGT is shown in
cyan (light blue). The numerical value for the highest EGT is located
below the bar. The EGT and Cylinder Head Temperature (CHT)
value for any cylinder may be shown by using the CYL 8LCT
softkey to select the desired cylinder. After a short period without
CYL SLCT softkey activity, automatic indication of the highest EGT
and CHT will start again.
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U.S.
1728PHAU8-03