Ahmer Posted October 21, 2018 Share Posted October 21, 2018 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. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted October 21, 2018 Share Posted October 21, 2018 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. Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 21, 2018 Author Share Posted October 21, 2018 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 Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted October 21, 2018 Share Posted October 21, 2018 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. Quote Link to comment Share on other sites More sharing options...
Moeed hassan Posted October 21, 2018 Share Posted October 21, 2018 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. Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 21, 2018 Author Share Posted October 21, 2018 Oil Scavenge kit installed all scavenge pressures are with in limit , several ground run carried out but ???? 1 Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted October 22, 2018 Share Posted October 22, 2018 (edited) 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 October 22, 2018 by pjvr99 Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 22, 2018 Author Share Posted October 22, 2018 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. Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 22, 2018 Author Share Posted October 22, 2018 (edited) 19 minutes ago, Ahmer said: Edited October 22, 2018 by Ahmer Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted October 22, 2018 Share Posted October 22, 2018 (edited) 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 October 22, 2018 by pjvr99 Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 22, 2018 Author Share Posted October 22, 2018 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. Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted October 22, 2018 Share Posted October 22, 2018 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? Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 22, 2018 Author Share Posted October 22, 2018 (edited) 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 October 22, 2018 by Ahmer Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted October 22, 2018 Share Posted October 22, 2018 Another thought, pull off the compressor rear bearing vent lines and check for oil - the lines are normally dry Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 22, 2018 Author Share Posted October 22, 2018 (edited) 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 October 22, 2018 by Ahmer Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted October 22, 2018 Share Posted October 22, 2018 no problem, this is how we all learn Quote Link to comment Share on other sites More sharing options...
Shola Posted October 27, 2018 Share Posted October 27, 2018 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. Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 27, 2018 Author Share Posted October 27, 2018 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. Quote Link to comment Share on other sites More sharing options...
Shola Posted October 28, 2018 Share Posted October 28, 2018 (edited) 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 October 28, 2018 by Shola Quote Link to comment Share on other sites More sharing options...
Ahmer Posted October 28, 2018 Author Share Posted October 28, 2018 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. Quote Link to comment Share on other sites More sharing options...
Shola Posted October 28, 2018 Share Posted October 28, 2018 (edited) 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 October 28, 2018 by Shola Quote Link to comment Share on other sites More sharing options...
DinoC-130 Posted May 3, 2020 Share Posted May 3, 2020 Hi. We have a problem with the gearbox pressure of a C-130 T56-A-15 engine. The pressure is low at Flight Level 100 and up. The pressure in gearbox is OK when start engine on ground. We verified oil tank, its OK; pressurization valve in the tank, its OK; shutoff valve, its OK; verified the oil lines, they are OK; changed Gearbox pump, the problem continues in the same conditions and changed the gearbox, the problem continues in the same conditions. Can someboby help us? Thank you very much. Quote Link to comment Share on other sites More sharing options...
DinoC-130 Posted May 3, 2020 Share Posted May 3, 2020 Sorry, I was forgot. An important detail about this problem is that when the problem occurs, the level oil tank increase. 1,5 gallons more or less when de gearbox pressure is 148 PSI. Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted May 11, 2020 Share Posted May 11, 2020 Dino, it sounds like you have a collapsing flexible line. Looks ok on the ground, but once oil is flowing through the inner wall is collapsing . Other possibility is the follower in the tank may be damaged. I have had this a couple times Quote Link to comment Share on other sites More sharing options...
superbigbig Posted June 10, 2020 Share Posted June 10, 2020 It may be that the oil filter is clogged or dirty, which causes the oil to enter the system and return the oil. The effect is not good. 先檢查1號軸承呼吸管拆開看是不是有漏油,如果有,可能主滑油泵內部防逆瓣失效了,導致回油效果不好,超過附件機匣的某一高度因為壓力差(虹吸效應)導致排入大氣中, 也可以觀察壓縮器下方是否有滑油得知 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.