Narrative:

After discovering we were going to install our 3rd hydraulic reservoir pressure manifold; I decided to figure out why the 2nd and original equipment manufacturer (oem) pressurization manifolds were not pressurizing the blue hydraulic reservoir to 50 psi. In fact; both [previous pressurization manifolds] units did not pressurize blue system at all. After a few hours of troubleshooting the problem and verifying on another airbus aircraft [in adjacent] hangar dock; I found that the left engine [pneumatic] supply line in the left-hand (lh) wheel-well on the forward (fwd) bulkhead (blkhd); was connected to a tee [fitting] which is the line that supplies all three hydraulic reservoirs; bypassing the [pressurization] manifold completely and probably over-pressurizing the reservoirs. And; I found the blue system pneumatic supply line (going to the hydraulic reservoir) was connected to a (union) [fitting]; which is the manifold supply connection from the lh engine. Thereby never supplying pneumatic pressure to the blue reservoir. So the lines were criss-crossed. Yes; both ['B'] nuts will fit on either connection and there is plenty of room for the lines to criss-cross and not chaff on anything. To me; neither line has been replaced that I could tell. And the engineering orders (east/os) that were accomplished in the same area should not have had the need to remove these lines. Please note; this condition was [found] on our inbound c-checks; [while] checking head pressure for the hydraulic reservoirs.

Related reports:

Google
 

Original NASA ASRS Text

Title: Mechanic describes what he found while trouble shooting for the cause of two previous replacements of an A319 aircraft's Hydraulic System Reservoir Pressurization Manifold; that allegedly had failed to pressurize the Blue System Hydraulic Reservoir from the left engine.

Narrative: After discovering we were going to install our 3rd Hydraulic Reservoir Pressure Manifold; I decided to figure out why the 2nd and Original Equipment Manufacturer (OEM) Pressurization Manifolds were not pressurizing the Blue Hydraulic Reservoir to 50 PSI. In fact; both [previous Pressurization Manifolds] Units did not pressurize Blue System at all. After a few hours of troubleshooting the problem and verifying on another Airbus aircraft [in adjacent] Hangar Dock; I found that the left engine [Pneumatic] Supply line in the Left-Hand (LH) wheel-well on the Forward (FWD) Bulkhead (BLKHD); was connected to a Tee [fitting] which is the line that supplies all three Hydraulic Reservoirs; bypassing the [Pressurization] Manifold completely and probably over-pressurizing the reservoirs. And; I found the Blue System Pneumatic supply line (going to the Hydraulic reservoir) was connected to a (Union) [fitting]; which is the Manifold supply connection from the LH Engine. Thereby never supplying pneumatic pressure to the Blue Reservoir. So the lines were criss-crossed. Yes; both ['B'] nuts will fit on either connection and there is plenty of room for the lines to criss-cross and not chaff on anything. To me; neither line has been replaced that I could tell. And the Engineering Orders (E/Os) that were accomplished in the same area should not have had the need to remove these lines. Please note; this condition was [found] on our inbound C-Checks; [while] checking head pressure for the Hydraulic reservoirs.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.