Date: 201911
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Medium Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Hydraulic Main System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate; Pre-flight
Result: General Flight Cancelled / Delayed; General Maintenance Action; General Release Refused / Aircraft Not Accepted
Contributing factors: Aircraft; Company Policy; Human Factors; Procedure
Primary problem: Company Policy

Narrative: While doing the walk around; I noticed two large streaks of a thick; black; and oily substance having run out of our wheel bay area and down the entire underbody up to the tail skid just short of the APU exhaust port. The substance had large running streaks now out of the slip stream and 'oozing' in long lines down the underbody of the fuselage. I accomplished the preflight/walk around earlier in New Orleans and had actually observed how clean the aircraft had been but now was remarkably coated in black 'guck.' This was brought to the attention of the Captain.We called Maintenance; and were met by a Technician who insisted the substance was a combination of dirt and water. The Technician and I went around and around a few times because I was insistent it was an oil based issue just judging from the color and consistency. Finally; the Captain threw his reflective vest on and said he would go out and only if the Technician could prove that it was only water and dirt that he would accept the aircraft. The Technician agreed and moments later they both returned confirming my earlier assumption that it was more than 'dirt and water;' it was leaking skydrol coming from our left main gear wheel bay.The Technician later took me into the wheel bay and showed me where not only was the one component - a rudder control component of some sort - leaking; but that it had sprayed fluid all over the wheel bay itself and was running out a weep hole under the keel beam. He also relayed to me; which is now where we get to the purpose of this [report]; that originally he was reluctant to even say anything that would break the jet out because Maintenance and Management was firing line technicians for breaking jets due to some judge's injunction against them. He was required now to wait for some contractor who could actually break the jet. He also said many maintenance technicians in ZZZ will NOT break jets out for any reason out of fear of losing their jobs. They will even drive by jets they clearly see that have problems and turn their heads. This absolutely mortifies me if THIS is the case. Not only is this flat out unethical; it's borderline illegal that our maintenance technicians are scared of losing their jobs if they find legitimate issues with our jets.I believe this event occurred because our Maintenance professionals are being pressured to clear jets to fly that are indeed NOT safe for flight out of fear that they will lose their jobs. I should not be fearful of our maintenance reliability or safety when I board our jets. I also know our passengers would be mortified if they knew this was happening.




Synopsis: Air carrier Pilot Flying reported refusing aircraft due to streaks of oily substance being present on the aircraft's exterior despite Technician stating otherwise.