pjvr99

i havent used the balancer yet so cant answer your question directly. however, a couple years ago we got a newly overhauled prop in the test cell. Everything was fine up to NGI. As throttle was advanced and blade angle increased, the prop noise and RGB vibration increased. Above 1000° TIT the noise was like someone or something beating on your chest - unpleasant, almost painful. RGB vibration was topping at 1.4 to 1.6 mils. We went through the prop records and everything seemed to be in order. We then did a loose blade and tracking check, which also checked good. While standing a distance away from the engine looking at the prop, we thought there was an optical illusion. It seemed that the #2 and #4 blades were narrower than #1 and #3. On measuring the width at various points from the tip to +- halfway in, we found the #2 and #4 blades around 2 inches narrower than the others. These 2 blades had a couple thousand hours on and had been reworked several times, while the other 2 were new. Essentially there were 2 blades working their asses off, and 2 just along for the ride. My thoughts are the noise and vibration were being generated by the 2 working blades being at a higher than efficient angle and probably very close to stalling. Just something to think about .....

WOW! System wide failure .... did you get it figured out? We've had a lot of wierd stuff with our EPCS birds, but this one is a first.

What aircraft model?

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First thought would be low pitch stop is not set correctly, however more info is required. What was airspeed, altitude and throttle position? Same for other engines and their indicated torque?

I've been down this road before - the numbers his fleet manager is insisting they use are not correct. My test cell has digital and analogue torque indication. The digital easily spans numbers like that, the analogue guages cannot. I was proven right when my boss had one of the tm i failed sent to RollsRoyce for evauation. Report came back with 7 defects including excessive twist (overtorque) of the torque shaft. The tm unit had been overhauled by another facility

all i can say at this point is the numbers you are trying to use are wrong. follow your job guide or tech orders for doing tm calibration, NOT the numbers given to you

If torquemeter stamped number is 29540 then corrected cal-A of -4000 would give corrected cal-B of 25540. Assuming ISA conditions and 72% rpm, you would be looking at 709"lb torque calculated. Setup indicator as per 1C-130H-2-77JG-00-1 77-10-04. A difference of more the 50"lb will require corresponding adjustment of the guage. A difference of 750"lb requires tm remove from service. Try my min torq calculator if I am not clear ..... Perf_PPC_v2.1.xlsx

no minimum value stamped on tm. T.O. says unload engine by turning off bleed air, generator and hydraulic pump. Then move throttle slightly forwards or backwards to obtain LOWEST torque indication. Adjust CAL-A/CAL-B -4000/25850. If the difference between INDICATED torque and CALCULATED torque is more than 750"lb reject torquemeter and return it to overhaul.

However I did find this .....

.... I'm going blind ....

APN = Aircraft Production Number? If so, its on the data plate above the flight engineer station

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Sounds like a bad speed valve ..... when you change the valve, take a good look at the drive socket in the ADH for excessive wear ..... another culprit could be the scoop anti icing valve - they have a tendency to pop open at high power settings when they get older

The engines have 2 speed settings, low speed ground idle and normal. Low speed is used to start and stabilize the engine, and also to do minimum torque calibration. Engines are generally held in low speed for taxi as it is easier to control oil temperature, than in normal. The #3 engine is sped up to normal to provide extra bleed for a quicker start on the other engines, and to provide air for the air conditioning packs. The APU provides +-40psi air pressure (unloaded) while an engine provides 80 to 100psi, although this is regulated to 70psi on some models Also use of low speed reduces fatigue on turbine assemblies

There is nothing in the engine or RGB that can cause a pitchlock condition. However, I'm wondering whether crew is giving correct debrief. You mentioned problem occurs during descent. If the NTS clearance is tight and pilots throttle back too far too quickly, they may be engaging NTS system momentarily - query the crew on that.

How is the in flight check being Performed? What steps? What is or is not happening?

Please confirm that the following parts were NOT transfered from one propeller to the next when the propellers were changed: valve housing pump housing PITCHLOCK regulator brass barrel nut Thing that sticks in my mind is the PITCHLOCK system is essentially mechanical, meaning once a COMPLETELY different propeller is installed the problem should go away. I wonder if the problem being experienced isn't maybe an engine roll-back .... this is just a thought

For the GTCP85-180 series we used T.O. 2G-GTCP85-41-1 ...... I don't know what the commercial equivalent is

Synchro operation can appear normal, but still cause trouble, which is why I suggest running the sync tester. You mentioned that mechanical governing has no effect - does that mean the crew put the prop to mechanical before landing and it still pitch locked?

When you say "3 propeller assembly changed" does that mean 3 different pump and valve housing? If so, you will want to run your sync tester - sounds like a synchrophaser or sync rack problem, or a wiring problem in main control conduit. Bearing in mind PITCHLOCK can only occur with low fluid level or overspeed conditions

Ah! Sounds like fun.

What are you doing with it .... ?

Finally found the correct info: Legacy C130E/H APU model is GTCP85-180L, PNo 381116-1- 3/5/6/7/8/9 C130 APU upgrade model no GTCP85-180LE, PNo 381116-3 L382 model no GTCP85-185L, PNo 381252-1-2

GTCP85-180L is valid model no for E and H model aircraft, as well as the modified GTC aircraft. Part numbers differ because the -185L used in the upgrade has intake screen rotated requiring relays and other parts to be repositioned. This means changes to the wiring harness and fuel, oil and pneumatic lines. GTCP85-180L come with part numbers 381116-1- 3/5/6/7/8/9