I believe I have spotted a bug in when the engine oil temperature failure is triggered.

 

If I allow the engine oil quantity to drop too low without topping it up, during the descent, and particularly in turns during the descent, the engine oil quantity can fall into the 'low' zone. This always seems to happen to the right engine - it seems to use more oil than the left.

 

When the oil quantity falls into the low zone, it immediately triggers the Engine Oil Temperature failure. The problem with this is there is then no way of stopping the oil temperature rising without manually cancelling the failure in the FMC.

 

The checklists suggest increasing the throttle to mid-way to cool the oil, but as the failure has already triggered, it doesn’t have any effect. Also, after the turn, the oil quantity usually goes back into the normal zone again, and so the oil temperature should stop increasing at this point even if no action is taken.

 

Should the Engine Oil Temperature failure not trigger until the oil temperature is actually in the red zone? This would allow the possibility if increasing engine power in order to cool the oil down.

Just a bump to say I've experienced this behavior twice as well, under the same conditions as above.  Engine oil overheat during descent, I fly with random and service-based failures all OFF, but this happens anyway.

 

Not sure what the cause is.

 

-Daniel Hamilton

Haven't seen this as I try to observe the minimum oil quantity required for engine start and fill up if needed, submit a support ticket and report the issue, if it is a bug then hopefully they can fix it for sp1c

I've raised a support ticket.

 

The oil quantity for the right engine was about 13 Qt when I took off. I've just done a quick search on the internet, and it seems the minimum quantity is 18 Qt, which is probably why I got the issue in the first place.

 

 

but as the failure has already triggered, it doesn’t have any effect

 

Interesting, FCOM table on pg 7.40.4 lists the ENG OIL TEMP advisory message for RR or PW engines not GE; but, QRH 7.64 includes the steps you referred to and a landing as soon as possilble under certain conditions.

I've raised a support ticket.

 

The oil quantity for the right engine was about 13 Qt when I took off. I've just done a quick search on the internet, and it seems the minimum quantity is 18 Qt, which is probably why I got the issue in the first place.

Yup, minimum required for engine start is 23qts, minimum for engine running at idle is 18