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Section 4
Normal Procedures
Power Settings – Use maximum continuous power until the airplane reaches a safe altitude
above the ground. Ensure the propeller RPM does not exceed the red line limitation. It is
recommended to use full throttle and 2600 RPM in climb because this setting provides the
engine with extra fuel for cooling at the slower airspeeds. When changing power, the sequence
control usage is important. To decrease power, decrease manifold pressure first with the throttle
control and then decrease RPM with the propeller control. The traditional practice of initially
squaring power settings (for example, 25 in. MAP and 2500 RPM) is an acceptable procedure,
but not required. The engine's turbochargers keep manifold pressure constant from MSL to
approximately 18,000 ft.
During normal climb operations above 18,000 feet, a minimum engine
condition of 2,200 RPM and 15 in.Hg of manifold air pressure are required
to insure proper turbocharger operation is maintained. If engine operation
below 15 in.Hg of manifold air pressure is necessary, the fuel mixture must
be properly leaned or engine stoppage will result.
Continuous overboost operation may damage the engine and require engine
inspection.
Vapor Suppression – The vapor suppression rocker switch must be turned on in the following
situations:
Operations above 18,000 ft.
•
If TIT is rising above 1460ºF at full power with the mixture full rich (at any altitude).
•
Once engine temperatures have stabilized and if the aircraft is below 18,000 ft, the vapor
suppression switch may be turned off.
The vapor suppression switch should also be turned on any time the engine is not running
smooth or it is suspected there is vapor in the lines. Vapor in the lines is most likely to happen in
hot weather or at high altitudes.
NORMAL OPERATIONS ABOVE 18,000 FT
During normal climb, cruise and descent operations above 18,000 ft., a minimum engine
condition of 2200 RPM and 15 in.Hg of manifold air pressure are required to insure proper
turbocharger operation is maintained. If engine operation below 15 in.Hg of manifold air
pressure is necessary, the fuel mixture must be properly leaned or engine stoppage will result.
CRUISE
Flight Planning – Several considerations are necessary in selecting a cruise airspeed, power
setting, and altitude. The primary issues are time, range, and fuel consumption. High cruise
speeds shorten the time en route, but at the expense of decreased range and increased fuel
consumption.
Cruising at higher altitudes increases true airspeed and improves fuel consumption, but the time
and fuel used to reach the higher cruise altitude must be considered. Clearly, numerous factors
are weighed to determine what altitude, airspeed, and power settings are optimal for a particular
RC050002
4-28
NOTE
WARNING
Initial Issue of Manual: November 10, 2004
Latest Revision Level/Date: A/12-01-2004
Columbia 400 (LC41-550FG)
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