XtremeAIR XA41, Maintenance Manual

Page: 257 / 284

Maintenance Manual XA41/XA42
AMM-XA42-0040-001 C.00
Page date: Page 3
25.09.2018 Chapter 79
79-00-01 Christen Inverted Oil System
The Christen inverted oil system is a gravity oil system. A connection to aircraft power
sources is not necessary. The system is applicable for all flight attitudes and also for
negative-g flight. For a schematic illustration of the christen oil system, refer to Figure 79-2
and Figure 79-3.
During normal flight (Figure 79-2), the weighted ball valve at the top of the Christen 803 oil
separator is open. Thus, blow-by gases from the engine crankcase go from the breather port
to the top of the oil separator. Then they go out through the overboard breather line.
With the Christen 802 oil valve, the top ball valve is closed and the bottom valve is open.
Thus, oil flows from the sump out to the oil pump and to the engine lubrication points.
Figure 79-2: Schematic illustration of the Christen oil system during normal flight.
During an inverted flight or during negative-g maneuvers (Figure 79-3), engine oil falls or is
pushed up to the top of the engine crankcase. The weighted ball valve in the oil separator
closes and prevents an overboard oil loss through the top of the oil separator.
Blow-by gases from the engine crankcase go from the sump to the bottom of the oil
separator and through the overboard breather line. The top ball valve of the oil valve is open
and the bottom valve is closed. Thus, oil can flow from the breather port to the oil valve
through the sump fitting. Then it flows to the oil pump and to the engine lubrication points.
Oil in lines which does not go back to the sump during the change from normal flight to
inverted flight, drains into the oil separator. During periods of normal flight, this oil goes
back from the bottom of the oil separator to the sump. Thus, only minimum oil loss occurs.