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Ahmer

Oil lose inflight

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No3 psn engine oil lose during escanding of the aircraft , all normal at ground and level flight but escanding & nose is high it's start loosing oil from mast drain. Any advise from ur side. 

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Change your "Oil Tank Pressurizing valve" located on the oil tank.

 

This valve "closes" as the aircraft climbs to pressurize the oil tank at higher altitudes (10-18,000') which pushes the oil out of the tank to the pumps. If it fails to close the pressure is too low inside the tank and indicated pressures will drop as the aircraft increases altitude.

 

The oil pressure will return as the aircraft descends so your crews can start the engine back up at a lower altitude and not land three engine. 

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There are two type of P&D valve( 3.5+-.25 & 5+-.25) wt u think which was good for T56 engine. More over we replaced P&D Valve but result is same during escanding. Regards 

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OOPS miss read the last part of your post and agree the pressurizing valve would have no effect on this issue.

 

The Oil loss may be due to excessive back pressure from the scavenge system. There is a check you can do but I haven't done that in many years. 

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Both valves r good but i think 5 psi D valve would b more reliable.... 

And for this oil loss issue there is a oil scavange kit available and by using this kit we can determine the back pressure at different points of oil system which will help us to isolate the fault.... 

REGARDS. 

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Oil Scavenge kit installed all scavenge pressures are with in limit , several ground run carried out but ????

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Lockheed Service News V18 #3 contains a brilliant explanation of causes and troubleshooting

of oil dumping. It was later made into a service bulletin. I suspect you may be looking at RGB 

scavenge failure

 

Edited by pjvr99

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13 minutes ago, pjvr99 said:

Lockheed Service News V18 #3 contains a brilliant explanation of causes and troubleshooting

of oil dumping. It was later made into a service bulletin. I suspect you may be looking at RGB 

scavenge failure

 

Pjvr99 u think RGB nose scavenge pump faliure, I also consult that service news and changed RGB, But in OCF problem repeated.   

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What is the difference in indicated oil quantity with engine running at 100% rpm and indicated oil qty

immediately when engine is shut down (no rotation)?

 

During ascent/descent are the oil pressures steady, or is there a fluctuation? Is there any fluctuation

on the ground?

 

Did the engine go across test cell before going back to aircraft?

 

Edited by pjvr99

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3 minutes ago, pjvr99 said:

What is the difference in indicated oil quantity with engine running at 100% rpm and indicated oil qty

immediately when engine is shut down (no rotation)?

 

At 100 % rpm the oil quantity is between 7 to 8 USG & after shut down it's come 11 USG approx.   

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OK. big scavenge problem. How is oil temperature?

 

Pull off lower E-duct from 14th stage. check the #2 & #3 bearing lines visible for oil staining. After

that check #2 & #3 bearing lines to the external scavenge pump that they are not blocked.

 

Heve you changed main oil pump yet?

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27 minutes ago, pjvr99 said:

OK. big scavenge problem. How is oil temperature?

 

Pull off lower E-duct from 14th stage. check the #2 & #3 bearing lines visible for oil staining. After

that check #2 & #3 bearing lines to the external scavenge pump that they are not blocked.

 

Heve you changed main oil pump yet?

Oil temp was with in limit. We replaced p/sec main oil pump .but we not find any good result....We not removed and checked 2 & 3 scavenge line for blockage. We removed and send for GOH.

Edited by Ahmer

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Another thought, pull off the compressor rear bearing vent lines and check for oil - the lines are normally dry

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9 minutes ago, pjvr99 said:

Another thought, pull off the compressor rear bearing vent lines and check for oil - the lines are normally dry

That's line checked it's ok , but we think may be problem was inside the no3 bearing  scavenge line .so removed and send for GoH. Tnx for sharing ur expert guidelines. 

Edited by Ahmer

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On 10/22/2018 at 5:15 AM, pjvr99 said:

Lockheed Service News V18 #3 contains a brilliant explanation of causes and troubleshooting

of oil dumping. It was later made into a service bulletin. I suspect you may be looking at RGB 

scavenge failure

 

We had a similar problem on our aircraft.  The engine was dumping oil in flight. Using ghe Lockheed Service News pjvr99 spoke about, We ascertained that the problem was due to oil accumulation in the accessory drive housing. As recommended by the Service News, We ran the engine at cruise power for 30 minutes. At the 29th minute, there was oil dumping as highlighted in the Lockheed Service News. We therefore confirmed that the problem was due to inadequate scavenging of oil back to the reservoir. You need to run the engine for minimum 30 minutes for the dumping to begin. We replaced the main engine oil pressure pump as well as the external scavenge pump, both on the accessory drive housing. Please note that you must bleed the main oil pumpbafter installation by loosening the back vent of the pump and then motoring the engine until oil gushes out of the bleed point. This procedure  solved the in-flight oil dump in our case. You may wish to try same.

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1 hour ago, Shola said:

We had a similar problem on our aircraft.  The engine was dumping oil in flight. Using ghe Lockheed Service News pjvr99 spoke about, We ascertained that the problem was due to oil accumulation in the accessory drive housing. As recommended by the Service News, We ran the engine at cruise power for 30 minutes. At the 29th minute, there was oil dumping as highlighted in the Lockheed Service News. We therefore confirmed that the problem was due to inadequate scavenging of oil back to the reservoir. You need to run the engine for minimum 30 minutes for the dumping to begin. We replaced the main engine oil pressure pump as well as the external scavenge pump, both on the accessory drive housing. Please note that you must bleed the main oil pumpbafter installation by loosening the back vent of the pump and then motoring the engine until oil gushes out of the bleed point. This procedure  solved the in-flight oil dump in our case. You may wish to try same.

Shola, the problem is not on ground & normal level flight, problem is start with aircraft escanding (nose up ) in flight.engine start oil lose.engine run several time on aircrft/test cell.all suspected components replaced result is same in flight.oil pumps both p/sec, heater strainer, scavenge filter,and RGB .finally engine send for GOH.

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6 hours ago, Ahmer said:

Shola, the problem is not on ground & normal level flight, problem is start with aircraft escanding (nose up ) in flight.engine start oil lose.engine run several time on aircrft/test cell.all suspected components replaced result is same in flight.oil pumps both p/sec, heater strainer, scavenge filter,and RGB .finally engine send for GOH.

This problem you described could be as a result of bad oil tank cap. Many a times, the gasket for the oil cap may be worn or the cap not properly locked in place. During flight and with pressure differential between inside the oil tank and outside the tank, coupled with the venturi effect of the drain system, oil could be sucked from the reservoir to the drain during flight. Another possible cause might be a failed RGB external scavenge pump. Unfortunately,  the overhaul centre might not tell you the real problem. 

Edited by Shola

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2 hours ago, Shola said:

Another possible cause might be a failed RGB external scavenge pump. Unfortunately,  the overhaul centre might not tell you the real problem. 

We checked all tank cap seals and replaced RGB as I written above but result is same , and there is no external scavenge pump of RGB.RGB have two scavenge pumps main & nose scavenge pumps which are inside the RGB.

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11 minutes ago, Ahmer said:

We checked all tank cap seals and replaced RGB as I written above but result is same , and there is no external scavenge pump of RGB.RGB have two scavenge pumps main & nose scavenge pumps which are inside the RGB.

Forgive me for the mistake. I actually wanted to refer to the main RGB scavenge pump. The nose scavenge pump is probably to remove oil back to reservoir when the aircraft is nose down. If the fault is with the main or nose RGB scavenge pump,  then, it was a good decision sending the engine for general overhaul. 

Edited by Shola

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