bleed air leak

[sharif101]

GTC bleed pressure 42psi.leak check (30-15) 7.5sec.i changed flow control shutoff valve,cargo,flight deck shutoff valve,ATM shutoff valve,both wing isolation valve,Empannage anti icing & pressurr gage.Check all anti iceing vale,starter control valve,wing bleed valve,eng check valve.cargo comparment all duck checked.no leak found but problem not overcome.previous leak checked founf 12 sec.

please give idea

[Steve1300]

Well, you don't say that there is any difference with the engine bleeds open or closed, but that needs to be checked. If the problem goes away with the bleeds closed, at least you know whether or not to concentrate on engine bleed air leaks and which one.

When you say that all ducts have been checked, are you saying that you have gone with your hands down each and every pressure duct by hand? All the way down the cargo compartment, with the bleed air ducts pressurized, you really need to get on a ladder and check the entire length. Also, make sure you check the external air connection to see that the check valve there isn't bleeding through.

It gets expensive changing parts without finding the leak source first.

[NATOPS1]

Trip both of your wing isolation valves closed and see what your time is then we can start to help... have you checked the external air connection?

[sharif101]

if both isolation valve close then time is 5 sec

extral air check valve is ok

if eng bleed closed than time is 6.5 sec

[sharif101]

if isolation valve closed then time is 5 sec

external air check valve is good

did not try with external air

if eng bleed closed then time is 6.5 sec

[NATOPS1]

Ok,

Start gtc with both wing isolation valves open and all engine bleed air valves open. record time ___.

Close #1 engine valve record time___.

With #1 closed, close #2 engine valve record time___.

With #1 and #2 engine valves closed, close Left wing isolation valve record time___.

With #1 and #2 engine valves and Left wing isolation valve closed, close the #4 engine valve, record time___.

With #1, #2, #4 engine valves, Left wing isolation valve closed, close the #3 engine valve, record time___.

With #1, #2, #3 and #4 engine valves, Left wing isolation valve close, close the right wing isolation valve, record time___.

[sharif101]

problem was gtc load control valve exhaust point.change load control valve.now leak check found 18 second

[bobdaley]

Sharif

Just curious, what Herk are you working on in the Congo. The only one I knew of was 4416 9T-TCB. Is it flying?

Thanks

Bob

[NATOPS1]

Glad you found the problem. Good job!