Low Oil Pressure

[airbus172]

At what point would you do a percautionary shutdown of a twin turbine engine when the oil pressure dipps into the yellow ark. Its in the upper half of yellow and stable. Oil temps are good and all else is fine. You are flying at night - does that make a difference? Do passengers? No emergency checklist until oil pressure light comes on at the lowest point of yellow ark. The POH sais as soon as "practicable", so I need your experience.
Happy Holidays

[sycamore]

Decision,decisions, decisions! Thats what it(airmanship, captaincy, etc ) is all about.

You have a torch,so go and look at the engine, fairings, exhaust, to see if you have any coNfirmatory signs( the exhaust b`cos you may have an internal leak, and you may see a difference). If you are pressurised and have an internal leak you may start getting fumes into the cockpit---OXYGEN?

Check your safety altitude , and your single-eng. cruise ceiling, if you have to shut one down.
Find your nearest safe diversion airfield and divert.

It may be a gauge problem, it may be an impending catastrophic failure, but it probably won`t get better.It may be prudent to shut it down early rather than end up having it grind to a halt just when it will cause you more embarassment.

If things got really sticky later you may be able to do a restart .

There really are so many variables, and guidance should always be sought from the Flight Manual; however, that list of emergencies is not always all-encompassing, so that is where you have to apply your own( or others) experience, and systems knowledge

Remember, it`s much better to be down here supping a coffee
WHILST AN ENGINEER CHECKS IT OUT, THAN UP THERE, when it`s gone from precautionary, to a full emergency.......

I`m sure others will have a wide variety of advice , as usual, but it would help if you were more specific regarding a/c type and area of operations.

Safe flying anyway....

[604guy]

You say "turbine" but you might want to specify fan or prop?

[lomapaseo]

Follow the SOPs

If you're left with any lee way after that, remember that just one odd-ball parameter is historically of little concern.

Catastrophic problems associated with oil system parameters are extremely rare associated with only a single flight.

[m&v]

This concern came to light with the advent of ETOPS.At one time crews shutdown their engines for the oil press'/quantity indications.Domestiacally no problem,in the ETOPS field regarded differently due to the fact that too many shutdowns led to the LOSS of the ETOPS privelges(engines have to meet a specific total of hours per shutdown)..Ergo press' put on the crews to really have a 'Failure' prior to S/D..This lead to some paper being out out by the 'engine' people-what the 'true 'indices are etc.
Crews then ran the eng at 'Idle' thrust,and changed Alt etc
,until they were forced to S/D....Anything to avoid the egine stopped...Haven't heard of too many s/d driftdowns lately.

[sycamore]

Remember guys, engineers sit at desks and pontificate, and like to see all straight-line graphs in accordance with their theories.They are not the risk-takers...
Find out how many engines have been losing oil pressure, and the flight has had to" change alt" during ETOPs. If the oil pressure reduces , then the system is failing.Why is it failing?

All they appear to be doing is hiding their heads in the sand.Remember, you too can be a statistic,... for all the wrong reasons!!

[airbus172]

sorry for the lack of specifics. No SOP's to deal with the situation. We were flying a 19 seat turbo-prop with garrett engines in the canadian north. I was of the opinion that we should have kept the engine as long as the other parameters were ok (no indication on engine that there was a leak and we are not pressurized). The captain however, wanted to save the engine and not find that it "grinds to a halt" when we are short final or deciding to overshoot. Then, I thought it was too early to shutdown but in hind sight I think he was right. Sooner or later I will be forced to make the decision so I wanted advice from you guys/girls.

[lomapaseo]

Sycamore

Fortunately intelligent folks ask questions before deciding for themselves.

The trained intelligent among us learn to ask the right question of the right people.

It is usually the arrogant that decide for themselves beforehand that no answer will serve their preconceived notions.

[Intruder]

Primary guidance should come from your Non-Normal Procedures Checklist. Other factors specific to the flight may alter them somewhat...

If you're flying a single-engine airplane, shutting down the engine is a last-resort procedure. OTOH, in a 747-400 a single engine shutdown is not necessarily even a reportable emergency. Further, your experience and knowledge of specific engine characteristics may help the decision process.

[GlueBall]

Shutdown of a jet engine, as a first step, requires the respective throttle (power lever) to be moved to the idle position. It's good common sense to reassess the engine indications: The oil indications may stabilize at reduced RPM. Better to have an engine at idle power than to have an engine with no power. The rule is: Never get into too big of a hurry to shut down an engine.

[BoeingMEL]

Lots of really good advice here... perhaps the most important being "don't be in a hurry to shut it down". I've had a couple of oil prex probs with PT6 engines...(Be1900) with the needle only just in the yellow arc (ie almost in the green). Remember that yellow is the CAUTION band.... but if the loss of pressure has resulted from gradual loss of oil, it will get worse! Speaking personally, if flying over any type of inhospitable terrain (including water) my preference was to keep the suspect engine at low idle and therefore immediately ready to return to work. (Even with props feathered, these things make lousy gliders if you lose number 2) Actions quoted above only of course if not covered by non-standard ops. ps: in each case above, problem was guage/sender bm