For Your Safe Flight
Page 21
Cruise
After the engine is warmed up, use LeanFind to lean the mixture.
Suggested setup:
Percentage
view
Automatic mode
Be alert for:
•
uneven EGTs or CHTs (carbureted engines).
Make fine adjustments to throttle, then RPM,
then mixture to level the display columns.
•
abnormal patterns of EGTs and CHT. (see
“Diagnosing Engine Problems” on page 22).
Descent
Suggested setup:
Percentage
view
Manual mode
Be alert for:
•
CLD: shock cooling alarm is set to –60°F.
Average cool rates of –40°F/minute to
–60°F/minute are normal, depending on the
engine size.
Shock Cooling
Cooling the cylinders too fast can result in cracking and eventual failure.
Lycoming Service Instruction 1094D (March 25, 1994) on
Fuel Mixture
Leaning Procedures
states:
“At all times, caution must be taken not to shock cool the
cylinders. The maximum recommended temperature change
should not exceed 50°F per minute.”
JPI checks shock cooling on all cylinders displaying the highest
reading cylinder.