Following on from my other post. Oil PRESSURE!

[flying dog]

Thanks to all who have contributed to my other discussion/thread about engines - car vs plane.

 

OIL pressure......

 

Ok, so putting aside the light which was mentioned in one of my posts.

 

If you have a pressure gauge for the oil:

 

When do you start producing bricks when the gauge goes down?

 

To keep it easier I think percentages would be best used.

 

5%, 10%, 20%, 30.... ????

 

Again, open for discussion.

 

 

[jetjr]

When somethings actually wrong Oil pressure usually falls fast ie seconds and temp will jump.

 

BUT if drops more steadily, when in yellow, be planning fast where your going to land, and be ready to shutdown.

 

Into Red, your already too late to shutdown without some damage, and its emergency time

 

Real issue is do you keep going when its falling but still in green. This has happened to me and I diverted to closest strip and kept going. Ended up flying for another hour or more to destination looking down the whole way.

 

Reason I did, being a slow loss like this is highly likely to be a crook sender which it was. Oil temps were OK which is a good second check of oil status. If oil levels drop it will get hot long before pressure drops.

 

This is just my opinion so please take it as that and make up your own mind

 

 

[flying dog]

Ak Ak Ak Ak......

 

Green Yellow Red......

 

Didn't I specify PERCENTAGES!!??

 

I know there is usually an "ARC". When flying glass cockpit, it is a number (be it BAR or PSI) and if you see it going down slowly enough and not just GONE! When do you start to worry?

 

 

[jetjr]

I dont know of panels which dont have coulour coded sections for critical data like oil pressure, most have number AND coloured limits. Basically if its in the green or operational range its OK

 

BUT as someone else said Id start diagnosing problem the second you saw it vary from normal. Your severity of response would be related to the size and speed of the change in reading and if the Oil Press change is backed up with other data.

 

Each engine will have its own varation but with relief valve should make them pretty static

 

 

[jetjr]

Glad Im not the only whos had this happen

 

My oil cooler hose wore through sometime between start and take off, bit of oil smoke then lots, got to circuit height, pressure started to drop into yellow on downwind so shut down and did unpowered landing. Even had momemtum to get off ont taxiway

 

It dropped all the oil between takeoff and halfway downwind.

 

This was on my first solo Nav at Robinvale VIC. Managed to find new hose in town, borrowed some oil from another plane, cleaned up a bit and departed 3 hrs after first attempt. Still made it home before last light

 

Could have been much worse.

 

 

[Guest check-in]

Depending on the efficiency of your oil cooler, if you are slowly losing oil you may see a drop in oil temperature well before the pressure gauge does its heart stopping act. I have had several cases of this in larger aircraft (which have very efficient oil coolers) and in each case we saved the engine by pulling it back to idle and/or shutting it down before all the oil went overboard.

 

I did not expect the little Jabiru 2200 engine to behave the same way, as I assumed that with such a small sump and small cooler, any loss of oil would be accompanied by a rise in temperature. But it happened that I lost most of the oil on one flight, when it siphoned overboard. It was extremely hot that day (time of the Victorian bushfires) and I had been worried about high oil temperature. But the temperature went low first, a good 15 minutes before the pressure showed any noticeable decline, by which time I was primed to land asap. When I got on the ground there was less than a litre left in the sump. Thankfully, no damage, so once again, $$$ saved by paying attention to the temperature gauge.

 

Once stabilized in cruise after the climb, oil temp will soon settle down to a constant and will likely stay put until descent.

 

Any change in temps OR pressures not consistent with a power or speed change is cause to head for the nearest safe landing and investigate. Not to be confused with a gauge or sender failure. That's one for the individual to risk manage, depending on your faith in the engine and other factors such as distance to go, type of terrain etc.