Random Comments about my Expedition E350 airplane. My Oil Pressure reading is interesting. If I add a pint of oil, climb to cruise altitude and cruise a while, my oil pressure will be around 81. Gradually as the flight cruises longer times, the oil pressure will drop to 79 or 78. No problem.
(My picture shows Oil Pressure of 79 PSI. Further discussion ensues…)
A flight or two later, it might drop to 77, and that’s an indication that I should add a pint of oil. If I wait until the oil pressure reads 76, then next time I’m on the ground and check my oil with the dip stick, will definately be low! So I’ve set “77″ as my threshold Oil Pressure to know my oil level is still OK, but time to add oil soon. That’s hopefully a useful tip to other E350 pilots.. something not in the POH manual.
( I check the dipstick before every flight. I’m discussing Oil Pressures in the context of making a pilot feel re-assured that everything is OK, during a flight.)
My right and left fuel tanks seem like they are cross-connected. Sometimes this becomes a problem, like when at the end of a long flight, when the fuel tanks are getting low, with 15 to 20 gallons in each tank, when you enter a circuit and start making left-hand banking turns, you can have fuel “seem to” flow from the right tank into the left tank. When the right tank sensor reaches “0″, you get a scary warning audio Voice Annunciation about running out of fuel, and it kind of forces you to quickly turn the knob to use the left-hand fuel tank. I’ve never felt the engine hiccup from this, until recently, but I was doing something odd:
I had been flying in BC over mountains to Salmon Arm, and coming over the last mountain, I needed to slow down and lose a lot of altitude. So I did hard rudder-pedal “skids”. (These skids help the plane slow down.) Keeping the wings level while hard-pressing the rudder one way, it forces a gradual turn, and it also creates a very “un-coordinated” state with the ball in the turn coordinator pushed far to the side. That push also must be pushing the liquid fuel in the tanks sideways, and causes fuel flow away from the fuel-level sensor. This causes one tank to go completely to a “0″ fuel level (on the sensor), and you hear the scary warning.
So I was doing these skids in alternating directions, watching fuel flow back and forth from left to right to left to right tanks, which was fascinating. But the one time I let it get to “0″, I also felt my engine hiccup a bit, so I think the “0″ fuel was probably “True” at that moment! This taught me, Don’t do skids to drop altitude unless I’m also watching the fuel levels.
I forgot to look-, at the undersurface of the wings, to see if any fuel was “leaking” out of the “overflow” spouts, during these hard skids. ( The E350 has an amazing big powerful rudder (Vertical Stabilizer), with more ability to push the airplane sideways than Cessnas do. The pilots foot pedals control the rudder.)
From the Pilot’s Operating Handbook (POH manual), section 7, here’s a diagram showing the fuel system. I don’t see a Cross-Connection. So I assume it’s all a trick of time-averaging fuel-sensor readings.
Oh, one more odd thing to comment on. I had an 18 knot cross-wind landing the other day, at 90 degrees to the runway, and the plane was totally easy to handle as it crabbed on approach, straighted out for wheel touchdown, and taxing on wheels the rest of the way. The POH manual is saying a lower number, 15.
I’ve learned that 18 Knots cross-wind is fine for this plane. But maybe my “18″ is inaccurate. That number came from my G500 display. For example, here’s a moment when it is showing 10 Knot wind coming from the front-right of my plane at a 45 degree angle to my direction of flight.
So, I would have been seeing 18 knots Crosswind on my final approach, but in the final moments when my plane is closest to the touchdown on the runway, the winds were probably a little less than that.
March 31, 2013 update. Here’s a photo of my instruments, cruising at 10,000 feet over BC, near Lytton. I think my engine temperatures are excellent, now that I’ve learned better where they should be. I began this post talking about Oil Pressures. I stuck a label on my dashboard saying to “Add Oil at Pressure 77″. This applies to when I’m cruising at 10,000 ft. My picture below shows pressure of 79, which is good. I discovered, that its dependent on altitude. If I drop altitude to 8000, then instead of 79, it would be between 80-81. But I believe my “77 threshold” is valid at 10,000. I think to myself, Previously when I’ve landed and checked oil at 77, its been ok, but at 76, it was too low and time to add another pint. So this reassures me during flight that all is well.