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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 munirabbasi

  1. 23 hours ago, NATOPS1 said:

    The only explanation I can offer is the No 1 Blade is the reference blade based on the location of the pulse generator therefor  it is a know location from which a measurement/ adjustment of relative position can be made during operation.


    Munir Abbasi

  2. On 12/14/2019 at 9:36 PM, NATOPS1 said:

    good work!


    Anti-skid Control Box PCB A2 was burnt out what is reason behind it?

    Do not test ant-skid during while aircraft is taxing (IC-130B-1 caution) if the testing is  carried out during aircraft taxing what happen with the system.

    Munir Abbasi 

    Home of Hercules


  3. 2 hours ago, pmostafiz said:

    7B engine. At first start, starting to was 810 but on the same day at 2nd & 3rd start, starting tit was 780 & 760. So many time we found this happened. Can anyone tell me what is the reason behind this to reduce starting tit at 2nd start.

    What is selection of TD SWs. Null or AUTO

    Munir Abbasi

  4. On 12/27/2019 at 9:39 AM, NATOPS1 said:


    Unless I misunderstand, the No 1 Blade is shown at 12 O'clock for both the No 2 and No 3 Master prop selected.


    Can you rephrase your questions? Not sure what you are asking as it seems there are many different questions.

    "why the phase angle relation of No#3 Blade only with master."


    "Any dynamic reason opposite blade of No.#1 to No #3"

    If you see optimum blade angle relationships  phase angle measure opposite with No #1 blade to No #3 for example  20 degree angle lagging or leading to  No#3 to No#1 blade

    Munir Abbasi

  5. Hello propeller expertise

    Optimum angular relationship shown in diagram master of No #2 or No#3 with respect other slave with NO # 3 blade AT 12 O clock why the phase angle relation of No#3 Blade only  with master. Any dynamic reason opposite blade of No.#1 to No #3

    Munir Abbasi

  6. On 12/11/2019 at 8:05 PM, NATOPS1 said:

    When you say release do you mean AS the crew is pushing on them? Are they full anti-skid braking or normal to light pressure?

    Thanks ,Defect was rectified with sufficient hydraulic bleeding. 

    Munir Abbasi

  7. Hello Hydraulic expertise

    AT  60 KN brake release during landing ,The operation checked o ground  found normal with tester .Wiring of the system was checked satisfactory .Anti-skid control box replaced and sufficient hydraulic bleeding carried out but defected was repeated.

    Munir Abbasi

  8. On 12/30/2018 at 9:23 PM, NATOPS1 said:

    O got it guess I should read better... No idea, don't know, never knew or don't remember... I do seem to remember this was a question LONG LONG ago and it is not in our level of pubs.


    Munir Abbasi

  9. On 12/22/2018 at 11:10 PM, NATOPS1 said:

    The window heat is controlled by Thermistors not thermoswitches so the "temperature" is not the trigger but a resistance value of the thermistor. Each "window" has a code AB, AC cant remember them all, that represents the resistive value of the window; these codes determine how to connect it to your transformer to get the correct operating voltage.  

    Munir Abbasi


  10. 16 hours ago, hehe said:

    Normal brake accumulator has a restrictor because of anti-skid system.  Emergency does not have anti-skid 

    Anti-skid plus normal demand of brake application can deplete the accumulator rapidly.  The restrictor ensures the utility system pressure goes to the brakes instead of filling the accumulator.  

    The restrictor is free flow OUT of accumulator but restricted flow IN to accumulator.

    Acts like a priority valve for normal brakes.



    Munir Abbasi

  11. 5 hours ago, hehe said:

    That is a manual override button, similar to override on flap selector valve/landing gear selector valve/ etc...only used that maybe twice that I can remember.  Good for troubleshooting a valve that wont close when energized electrically but serves no purpose in the system operation


    Munir Abbasi

  12. 17 hours ago, hehe said:

    Ahmer is correct.  The "relief" for brakes comes from the power brake control valves.

    The selector valves do leak internally quite a bit once you get into the 4K+ range but thats not really the purpose of them. 

    Really depends on what year/model/brake system your aircraft has because there are quite a few differences between the systems (IE: anti-skid valves, 3k or 2030 psi metering valves, parking brake valves, single/multi disk/carbon brakes, etc)

    There are also 4 different selector valve part numbers depending on which aircraft it is.  

    Simple answer, no the selector valves dont have a relief valve

    See Image

    Munir Abbasi


  13. 3 hours ago, NATOPS1 said:

    High speed anything in the Herc is rare BUT in the case of dives there is the ability to have an increase in airflow through the prop which could cause NTS. This could happen with the throttle at flight idle power off or with power on at any setting above flight idle.  

    As the airflow increase the prop wants to drive the engine as the air becomes the drive force not the engine power.


    IF the NTS fails to increase the blade angle drag will be induced; an outboard prop will have more yaw effect than an inboard prop.    

    Would the prop pitchlock is a dynamic question and is dependent on the situation but in reality pitchlock prevents the prop from decreasing blade angle therefore again in theory the blade should continue to increase blade angle.


    ANYONE have the OLD 1960s "PROPORGANDA" illustrated little book that had all the little "engineers" and "mechanics" drawn in? There are some good explanations on this and other prop engine related topics.


    Munir Abbasi

  14. 1 hour ago, NATOPS1 said:

    You are missing the point on NTS in this condition. "Hi speed" dives are not a normal profile and this condition (NTS induced by hi speed airflow) is very rare especially with power on.

    Flight idle descent is common but airspeed is usually limited to prevent NTS (airframe limitations)  We usually see NTS at Flt Idle once we arrive at lower altitudes as the air gets more dense and we add a small amount of power to eliminate the NTS condition.


    NTS is a DIRECT input to the feather valve and bypasses the normal governor. 

    If there is an onset of NTS during a hi speed dive and a failure of the NTS system does not increase blade angle; drag will increase and the aircraft will yaw (original posters question) additionally pitchlock while it could/would come into play if the Rpm INCREASED TO 103.5 it is not a factor because the blade is not trying to decrease and while the normal governor should increase the blade angle to maintain RPM we are discussing failures not normal operations and the feather valve should have already commanded a blade angle increase.

    It is important to remember if the NTS continues to increase at aprox -4000 inlb TQ the prop should decouple which would actually be a very bad situation because the increase airflow which caused the NTS would now drive the "pitchlocked" propeller very fast and cause even higher drag.


    Munir Abbasi

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