Oil pressure drop at altitude?
in 912 / 914 Technical Questions
5 years ago
Hello all.
I climbed my Rotax 914 equipped Sling4 to FL125 this morning (testing oxygen systems).. It was a fairly hot day (ISA+22C). As we climbed through FL115 (100% power, 33” manifold Pressure, 5500RPM) I noticed that the Oil Pressure was low, fluctuating between 1.5 and 1.8bar. There was no drop in power, change in oil temperature, roughness or any other abnormalities in the engine.
We leveled off and reduced power to cruise setting of 30”. 5200RPM - no improvement in pressure.
At this stage I elected to return to nearest field - as we descended through FL110 the pressure improved and settled back at 2.7-3bar in the cruise, where it remained for the rest of the flight.
Does anyone have any suggestions as to the potential cause of this? Oil quantity is adequate (2/3 of the way up dipstick), oil was changed at last MPI 35hours ago. There is no oil on the underside of the aircraft nor any oil leaks in the engine compartment. I only use Mogas 95 Octane.
Thanks
Mike
I climbed my Rotax 914 equipped Sling4 to FL125 this morning (testing oxygen systems).. It was a fairly hot day (ISA+22C). As we climbed through FL115 (100% power, 33” manifold Pressure, 5500RPM) I noticed that the Oil Pressure was low, fluctuating between 1.5 and 1.8bar. There was no drop in power, change in oil temperature, roughness or any other abnormalities in the engine.
We leveled off and reduced power to cruise setting of 30”. 5200RPM - no improvement in pressure.
At this stage I elected to return to nearest field - as we descended through FL110 the pressure improved and settled back at 2.7-3bar in the cruise, where it remained for the rest of the flight.
Does anyone have any suggestions as to the potential cause of this? Oil quantity is adequate (2/3 of the way up dipstick), oil was changed at last MPI 35hours ago. There is no oil on the underside of the aircraft nor any oil leaks in the engine compartment. I only use Mogas 95 Octane.
Thanks
Mike
