Date: 201304
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
ATC / advisory: Ramp ZZZ
Aircraft component: Hydraulic System Lines; Connectors; Fittings
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Human factors: Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Maintenance Action; General Flight Cancelled / Delayed; General Release Refused / Aircraft Not Accepted
Contributing factors: Procedure; Aircraft
Primary problem: Aircraft

Narrative: I was the First Officer. During the preflight inspection I discovered hydraulic fluid leaking from the left hand main landing gear area. Fluid was running down the landing gear on to the tire and puddled underneath the brake assembly area. I returned to the flight deck and found the green system reservoir quantity to be below limits. I reported the condition to Captain; made a write up; and verbally reported the log item to Maintenance. Maintenance quickly confirmed the hydraulic leak and started working the problem. A mechanic with a radio came up and turned on the yellow hydraulic system to pressurize the yellow and green hydraulic systems while mechanics inspected the wheel well area for leaks. After about 30 minutes; a Maintenance Supervisor came up and informed us that despite all the fluid found and the area found to be 'saturated' with Skydrol; they had not found anything wrong or leaking. He was going to leave the system pressurized for another 20 minutes and sign of the log item as lines tightened - no leaks found. I tried to be diplomatic and did not want to over step my bounds; but finally; in the interest of safety; I - and the Captain - had to say we were not taking the airplane unless they performed a procedure that would pressure the landing gear extension/retraction portion of the hydraulic system. Due to the location and nature of the fluid leak; we highly suspected this part of the system to be the source of our problem. The procedure was to pin the gear; place the aircraft in the air mode; and pressurize the gear actuator system by placing the gear handle in the up position. From my previous maintenance experience as an airline Mechanic and Supervisor; this seemed to be a logical and obvious troubleshooting step and; personally; a requirement before I would certify the integrity of the system in question. The method they were using only pressurizes and tests a small part of the hydraulic system. Not one of the five mechanics or Maintenance Supervisor even mentioned this procedure and were prepared to sign the aircraft off and send us on our way: very troubling to me. After performing this procedure; the Mechanic reported the hydraulic system was 'leaking like a sieve' and the aircraft would be going to the hangar. The flight was canceled and we were deadheaded to our next assignment.




Synopsis: An A320 was removed from service after a flight crew refused the aircraft because of a hydraulic leak which inadequate troubleshooting could not resolve until the full landing gear system was pressurized.