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Helieagle

205A-1

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Hey,

We are currently doing a test for the Low level switch to confirm that it comes on with 10 Minutes of Fuel Remaining. The Flight Manual says there is 2 Gallons unusable or 13 Pounds. We have made the light go out and then only drained from the Rear drains and have the light coming on at 325 lbs indicated. We have set the gage to read 0 Pounds when empty including the 2 Gallons as it is still included. Has anyone done the test recently and if so what was the Outcome. To the info in the MM and FM lead us to believe we are doing something wrong. But Logically with that standpipe and low level switch up about 6". We Have the One Electrical boost pump and the Air Driven. Any thoughts or experiences with this is greatly appreciated.

 

 

Thanks. HeliEagle.

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Hey,

We are currently doing a test for the Low level switch to confirm that it comes on with 10 Minutes of Fuel Remaining. The Flight Manual says there is 2 Gallons unusable or 13 Pounds. We have made the light go out and then only drained from the Rear drains and have the light coming on at 325 lbs indicated. We have set the gage to read 0 Pounds when empty including the 2 Gallons as it is still included. Has anyone done the test recently and if so what was the Outcome. To the info in the MM and FM lead us to believe we are doing something wrong. But Logically with that standpipe and low level switch up about 6". We Have the One Electrical boost pump and the Air Driven. Any thoughts or experiences with this is greatly appreciated.

 

 

Thanks. HeliEagle.

 

I remember reading this not too ling ago as we had a 212 that had similar problems......I'm just a meat servo up front...but if this helps, I take payment in bottled form :punk:

 

we both ejector pumps working?

 

Page 4

http://www.bellhelicopter.textron.com/MungoBlobs/342/475/rb_Q2_10.pdf

 

this paragraph may be of interest

Illumination of the low fuel caution light with a higher than normal fuel quantity is often associated with a leaking left tank flapper valve; allowing fuel to flow from the aft compartment forward, with the right tank compartments maintaining constant levels. This can also be associ- ated with an ejector pump that is not producing desired flow.

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Hi HeliEagle,

 

It's been a few years but I remember having an issue on a 205 where the wrong low level switch was installed. If memory serves me right if you have the bleed air boost pump installed the level was lower then if you have the electric boost pump. There's about an inch difference in the switch height. It might be worth while checking the P/N on the switch.

 

The flapper valve would be the other thing I would check out as suggested by R22Captain.

 

Hope that helps

 

Sean

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The aircraft should also be leveled with the plumb bob... Which means the back end up. This is closer to the actual attitude of the aircraft in flight. I believe there are a couple of different standpipe lengths (P/N's) that can be installed in the Bell medium series but I do not have a IPC in front of me to check. The low level standpipe and switch is in the leftside which is the same side as the bleed air boost pump. The bleed air boost pump usually runs at a higher PSI than the electric pump that is in the right tank therefore the left side fuel level may be slightly lower than the right. The capacitance fuel indicating system is totally seperate from the low level light and will read the actual fuel capacity which will be higher than normal if the right tank has more fuel in it. The actual test of when the light illuminates should be done in level forward flight as you cannot run the bleed air on the ground unless the aircraft is running. Bottom line .... Either the low level light comes or it doesn't. Check the flapper valve for the right washer stack up under the top bolts holdin the flapper on... If correct the flapper shouldn't leak. The hole in the inlet side that sits in the Venturi of the ejector pump is really small so I have always found it is either clear or plugged. If plugged you will have a boost pump cation light even though the boost pump light works. Hope this helps....

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The aircraft should also be leveled with the plumb bob... Which means the back end up. This is closer to the actual attitude of the aircraft in flight. I believe there are a couple of different standpipe lengths (P/N's) that can be installed in the Bell medium series but I do not have a IPC in front of me to check. The low level standpipe and switch is in the leftside which is the same side as the bleed air boost pump. The bleed air boost pump usually runs at a higher PSI than the electric pump that is in the right tank therefore the left side fuel level may be slightly lower than the right. The capacitance fuel indicating system is totally seperate from the low level light and will read the actual fuel capacity which will be higher than normal if the right tank has more fuel in it. The actual test of when the light illuminates should be done in level forward flight as you cannot run the bleed air on the ground unless the aircraft is running. Bottom line .... Either the low level light comes or it doesn't. Check the flapper valve for the right washer stack up under the top bolts holdin the flapper on... If correct the flapper shouldn't leak. The hole in the inlet side that sits in the Venturi of the ejector pump is really small so I have always found it is either clear or plugged. If plugged you will have a boost pump cation light even though the boost pump light works. Hope this helps....

 

 

Yup, we have verified pump numbers on the Standpipe that the low level switch sits on. We have also had a new low level switch from bell and still same results. Yup, we have it leveled by the plumbob. Both injector pumps are clear. We have done the test Static and with it running with same results. It coming on with 325lbs Indicated and verified with draining that there indeed is 325lbs when light illums. With Electric pumps the standpipe for the switch is like 1/4" higher I believe.Checked connections. Its Just odd this time around and can't nail it to the cause. The Flapper Valves are installed correctly aswell.

 

Helieagle

 

R22.. Cold hook ya up with some beer if needed. :)

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I have seen this on a 212. Check to see if the return line from the ejector pump isn't dumping fuel into the fwd part of the cell not the aft portion. This can result in the low lights coming on early.

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I have seen this on a 212. Check to see if the return line from the ejector pump isn't dumping fuel into the fwd part of the cell not the aft portion. This can result in the low lights coming on early.

 

check for a plug/cap line as well.......we had a low fuel light problem very similar

 

add fuel and the rh low level light would go you...but could never get the LH one out.

 

after tearing apart the LH tank we had found a shiney red plug someone forgot to take out when one of the crossfeed lines was installed. :huh: Line to rear dump valve.

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Have you checked the boost pump pressures are correct. If I remember right the l/h book pump is suppose to be higher then the r/h when you have dual electric boost pump. Also I have heard that if a check valve in the fuel manifold at the top of the hellhole is not working corrently that your boost pump can fill your r/h tank (where fuel quantity probe is) higher then your l/h tank ( where the low fuel switch is). I have never seen this but some thing I have heard. Open up both fuel cells and take a look while the boost pumps are on.

 

That is correct that when you have the helitrades dual boost pump the low fuel switch is 1/4 or 1/2 inch taller then stock. If the flapper valve is assembled corrently, cross feeds are not blocked, jet pumps are clean and low fuel switch is working correctly not much else you can do. I think that this is the norm, not a bad thing to have the fuel light to come on early anways. what is 10 min fuel anyway 100-150lbs. Add a 150 lbs and see where the fuel level is in relation to the switch. probably see it have half way up the standpipe anyways. Have fun playing in the fuel.

 

SW

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