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APU GTCP85-180L STOPS AFTER 20MIN


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  • 3 weeks later...
On 3/7/2019 at 6:56 PM, NATOPS1 said:

When it stops can you start it up immediately without any issues?

 

Help narrow the fault by running it for 20 min with the bleed air valve closed. Does it stop? 

Our GTC85-180L stopped at 20 minutes with bleed air valve closed. What is the likely cause please?

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As NATOPS1 asks, can the APU be restarted immediately or do you need to wait for a

time? Likely causes can be oil pressure, load control/acceleration thermostat, faulty

overspeed solenoid, or some electrical interruption. If you have an APU test stand

available, I would recommend running the APU there and try to duplicate the 

problem.

 

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On 3/24/2019 at 2:21 AM, pjvr99 said:

As NATOPS1 asks, can the APU be restarted immediately or do you need to wait for a

time?

It Starts normally!

Likely causes can be oil pressure (PRESSURE SWITCH CHANGED), load control/acceleration thermostat (CHANGED AND CALIBRATED), faulty

overspeed solenoid ( CHANGED), or some electrical interruption (??????). If you have an APU test stand

available, I would recommend running the APU there and try to duplicate the 

problem. (WE DONT HAVE ANY AVAILABLE ON SITE)

 

 

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thank you Paolo, have you checked the oil tank for contamination

or blockage? also check the oil supply hose (flexible) from tank for

collapsing. If it only cuts out under load, you may have a fuel 

starvation problem - take a look at the fuel filter on the fuel cluster

and also the filter up in the wheel well

 

just out of curiousity, is the APU part no 381116-1-() or 381116-3?

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On ‎3‎/‎25‎/‎2019 at 9:48 AM, PauloFerreira said:

With Bleed Air Valve CLOSED, it runs without problems!

Will the APU run without problems with the Bleed air valve open AND NO air conditioners or other bleed air load applied?

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On ‎4‎/‎3‎/‎2019 at 9:39 AM, PauloFerreira said:

Yes! The APU run's without problems!

Ok good.

The APU stops when you turn on an air conditioner, yes? Watch the EGT and see what it is reading when it stops.

Can you start an engine with the APU or does it stop?

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23 hours ago, NATOPS1 said:

Ok good.

The APU stops when you turn on an air conditioner, yes? Watch the EGT and see what it is reading when it stops.

Can you start an engine with the APU or does it stop?

The APU stops when i connect the generator and when i open the Bleed Air Valve!

Yes i can start an engine with he APU!

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Sorry for all the questions.

SO I fully understand:

How much fuel is in the number 2 tank?

Do you turn ON the fuel boost pump in the number 2 tank when operating the APU?

When you start the APU it will run normally with the bleedair valve CLOSED and generator OFF; WILL it run for more than 20 min in this configuration?

Will the APU run with the bleedair valve OPEN and gen OFF for more than 20 min?

When you turn ON the GEN how long before the APU stops?

 

 

Are you starting the APU with BATTERY power only or is External power unit connected?

 

 

 

 

 

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  • 2 weeks later...
On 4/19/2019 at 3:22 PM, NATOPS1 said:

Sorry for all the questions.

SO I fully understand:

How much fuel is in the number 2 tank?

MORE THEN 2500 Lbs

Do you turn ON the fuel boost pump in the number 2 tank when operating the APU?

NOT APPLICABLE iaw CHECK LIST!

When you start the APU it will run normally with the bleedair valve CLOSED and generator OFF; WILL it run for more than 20 min in this configuration?

YES! IT RUNS WITHOUT PROBLEMS!

Will the APU run with the bleedair valve OPEN and gen OFF for more than 20 min?

YES! IT RUNS WITHOUT ANY PROBLEM!

When you turn ON the GEN how long before the APU stops?

20 Min APROXIMATELY, THEN STOPS!

Are you starting the APU with BATTERY power only or is External power unit connected?

NORMALLY WE HAVE THE EXTERNAL POWER CONNECTED!

 

 

 

 

 

 

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Is your Battery always connected? Even with External power connected/ON the aircraft?

 

And to clarify you can start and run the APU for 20 min or more and ONLY AFTER the GEN is turned ON the APU will continue to run for (another) 20 min and then stop OR stops sooner?

 

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