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Aero Precision provides OEM part support for military aircraft operators across more than 20 aircraft


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Posts posted by pjvr99

  1. 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



    Also use of low speed reduces fatigue on turbine assemblies

  2. 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.

  3. 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

  4. 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? 

  5. 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

  6. 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



  7. 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

  8. Coordinator first thing to check, pot is probably loose. After that, take a serious look

    at thermocouple harnesses. We had a lot of similar problems last few years that

    were traced there. Also take a good look at the gimbal

    bushings, and ALL control rod-end bearings. Also check

    condition of the prop universal joint


    Let us know what you found 

  9. What is the LSGI TIT when stable after start? Also ff and Torque?

     If you shut down the engine and restart immediately, what are torque, TIT and FF? 

    What are NGI torque, TIT and ff?

    What are ff, torque and TIT at 900°C?

    What are OAT and pr altitude during these actions?

    Can you run a direct reading Guage for CDP during these checks?

    I don't see fuel nozzles changed on your list; while you're doing that, put borescope in and check combustion cans.



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