Jump to content

Archived

This topic is now archived and is closed to further replies.

Islam

Two actual maintenance tests

Recommended Posts

I never thought that this test would work correctly in the NGX, as lots of 737 engineers do not know it in real life!!Here it goes: Sometimes a hydraulic comonent called brake shuttle valve, happens to have some internal leak. This causes hydraulic fluid from different systems, to leak into one another, causing at the end a decrease in the hydraulic quantity of one system, and an overfill in the other system.There no procedure in the AMM to correct such hydraulic quantity unbalance, except by draining and refilling. But experienced maintenance people know a little trick. That is to operate the parking brake and release it several times using only system A pressure, if you want to transfer hydraulic fluid from A to B. To do the opposite, you have to deploy the left reverser using standby system, then restow it. If you follow the hydraulic circuit in the AMM you would know why, but at the end, it surprisely happens correctly in the NGX, and the fluid is actually transferred!!!! I am really really astonished.Here is how to try it from cold and dark:1. Supply electric power.2. Make sure all hydraulic pumps are switched off.3. Put any one of the FLT CTRL switches into STDBY RUD position. Make sure the STDBY RUD ON light comes on. This ensures the standby pump is running.4. Now check the system page on the lower DU, it should read 100 for each system quantity.5. After you get ground clearance (kidding), deloy the left reverser.6. Observe system B quantity decreasing to around 97.8. Now restow, and the fluid will normally return to tank A to show you an overfill condition!!!!Now you want to correct this configuration:1. Return the FLT CTRL switch to normal position by closing the gurad.2. Operate only the A system pump.3. Now set and release the park brake several times... and Voila!!I need to tell you that personally I used this trick in an outside station when I was escorting one of our flights, and the captain compained about a hydraulic smell in the cabin. The reason was an overfill condition in system A, which caused the fluid to go up the pneumatic system and up to the air conditioning packs.The other so nice test that I tried on the NGX to find it working perfectly, is the pressurization test. Have you tried to close the doors, and close the outflow valve, and operate the packs to pressurize the airplane, then turn them off to see the leaking rate? Try this and you will love your NGX more and more.


Islam Alnady

EgyptAir 737 / 777 / A300-600 Engineer

 

AMD Phenom II / Sapphire 5670HD 1 GB / 8 GB RAM / Windows 7 / 64 bit / FSX Acceleration / PMDG 747 / Level-D 767 / PMDG 737NGX / Wilco 737CL / Saitek Aviator stick

Share this post


Link to post
Share on other sites

wow.. Way beyond my level of knowledge, but just knowing that this product actually simulates this is just... well... unreal... ;)Thx for sharing...Mas


Martin Jensen

Share this post


Link to post
Share on other sites

Oh yeah... really really unbeleivable!!!


Islam Alnady

EgyptAir 737 / 777 / A300-600 Engineer

 

AMD Phenom II / Sapphire 5670HD 1 GB / 8 GB RAM / Windows 7 / 64 bit / FSX Acceleration / PMDG 747 / Level-D 767 / PMDG 737NGX / Wilco 737CL / Saitek Aviator stick

Share this post


Link to post
Share on other sites

  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
  • Donation Goals

    AVSIM's 2020 Fundraising Goal

    Donate to our annual general fundraising goal. This donation keeps our doors open and providing you service 24 x 7 x 365. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. We reset this goal every new year for the following year's goal.


    43%
    $10,985.00 of $25,000.00 Donate Now
×
×
  • Create New...