Date: 202202
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Hydraulic Main System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Troubleshooting
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During the preflight walk around; I observed a small; approximately 5-inch piece of what appeared to be a piece [of] Teflon seal protruding from the bottom of the #1 engine at the nacelle seam. This discrepancy was reported to Maintenance and signed off before pushback. The takeoff; climb; and initial phase of cruise were all routine with the exception of slightly more turbulence than normal - nothing more than continuous light and occasional moderate; resulting in the seat belt sign being illuminated slightly longer and the FAs (Flight Attendant) being seated a bit more than normal. West of [the] river; the ride had smoothed out considerably; [so the] seat belt sign [was] off; and flight conditions became VMC.At FL360 approximately 200 NM east of ZZZ; we observed a G RSVR LO LVL ECAM. After running the complete ECAM; the CA (Captain); pilot monitoring; broke out the QRH and reviewed the entire procedure; including all of the INOP systems; most notably: GREEN HYD; SPLR 1+5; N/W STRG; NORM BRK; L/G RETRACT and REVERSER 1. We discussed the ramifications of continuing to ZZZ1 and after consulting Maintenance Control and Dispatch; decided that [requesting priority handling] with ATC and diverting to ZZZ would be the best and safest course of action. Our assumption was that there was a leak in the green hydraulic system as the HYD page indicated almost no fluid remaining in the green system. We were below max landing weight; so we accepted vectors onto the ZZZZZ Arrival and subsequently requested Runway XXL based upon the runway length. We calculated our landing distance to be approximately 6;000 ft. and Dispatch backed us up by calculating a stopping distance of 6;790 ft. Once coordination with Dispatch and Maintenance Control were completed; we ensured all applicable checklists were completed and briefed ATC; the FAs; and the passengers. We elected for the CA to take over as the pilot flying; and I assumed the duties of pilot monitoring during the arrival. We also elected to start the APU.When we were both comfortable with the state of the aircraft; our plan; and the field conditions; we began slowing the aircraft; configuring; and emergency-extended the landing gear at approximately 20 NM on final to Runway XXL. After executing the L/G Gravity Extension Checklist; we received indications that the gear was down and locked with the gear doors open; as expected. Shortly after extending the landing gear; we noticed blue procedural steps on the STS (Status) page for the approach to turn on both the green hydraulic pump and PTU; both of which we had secured in accordance with the original ECAM. After a brief discussion; we elected to turn both items on. However; within approximately one minute; we again saw the G RSVR LO LVL ECAM and promptly secured the green hydraulic pump and PTU in accordance with the ECAM at approximately 10 miles on final with the gear extended. Prior to touchdown; I made the PA call to brace; brace; brace" followed by a "remain seated; remain seated" call as we approached a safe taxi speed on the runway after touchdown. The landing was uneventful and we ended up stopping on centerline using emergency brakes around the 7 board; 9;000 lb. remaining. After the crash crew inspected the aircraft and reported fluid under the #1 engine; Company Maintenance evaluated the aircraft; pinned the landing gear; and initiated a tow to the gate. We executed the Tow-In Procedure and multiple PA announcements were made to keep the passengers in the loop with what was going on prior to and during the tow."


Second narrative: While cruising at FL360 to the east of ZZZ; an ECAM message stating HYD G RSVR LO LVL appeared on the upper ECAM. The FO (First Officer) was pilot flying; so I told him he had the controls and the radios; and I would handle the ECAM. I followed the ECAM and turned the PTU (Power Transfer Unit) and Green ENG 1 Pump off. While running the ECAM we noticed a few things; the PTU; prior to being turned off; had been automatically deactivated and the G HYD System was completely empty. Prior to our flight the system was at a nominal level; so we suspected a leak somewhere in the system. After completing the ECAM I referenced the QRH to see if anything was missed. I told the FO I was going to the number 2 radio to talk to Dispatch and Maintenance Control [and] used ACARS. A few minutes later I was conversing with Dispatch and Maintenance Control on XXX.XX MHz. Maintenance Control confirmed that HYD G RSVR LO showed on his side. At this point we were still east of ZZZ and throughout the flight I checked weather at airports in case of an emergency. Because of the massive low-pressure system moving across the US; many airfields east of ZZZ had low visibility; gusty winds; and blowing snow. The safest alternate was ZZZ and we; Dispatch and I; decided to divert there and not continue to ZZZ1. I did not know why the G System emptied and did not want to continue across the [mountains] where airfields are scarce; and possibly have another hydraulic issue and be down to one system. I asked Dispatch to check my performance calculations that I had originally given him; and [to] send an ACARS when he had done so. I told Dispatch I was about to [request priority handling] and start the divert to ZZZ. He and Maintenance Control had nothing else for me so we signed off. At this point I rallied with FO and told him we would now [request priority handling] and begin our divert to ZZZ. The FO was still pilot flying and primary on the radios. My FO is a probationary pilot so I told him specifically how to [request priority handling] and the information ATC would require. He did a fine job doing that as I listened in on the #1 radio. I did not want my FO to feel overwhelmed so I stayed with him in order to get the FMGC (Flight Management and Guide Computer) squared away for the divert. Once that was complete and the aircraft headed towards ZZZ; I told him I needed to talk to the FAs (Flight Attendant) and passengers. He was instructed; prior to any altitude changes; to confirm with me first.My brief with the Purser was concise and he received all necessary information. I had the FAs prep the cabin for evacuation in the event something went terribly wrong; the Purser had no questions. The passengers were then briefed on the situation. After FA and passenger briefs were completed; I rallied again with the FO. We were now in the descent; via the ZZZZZ Arrival. We requested the longest available runway at ZZZ; XXL; and told ATC to standby because we still had a few things to accomplish. I gave the FO a brief review of the situation [and] we reviewed all information that is required prior to running the descent checklist: approach; how it is to be flown; etc. We also reviewed how we would fly a go-around; if required with the gear extended. A brief was also given on a worst-case scenario vs. best-case. Prepare for the worst and hope for the best was our approach to this situation.I told my FO; a very good pilot; that I would land the plane because I wanted the responsibility. We configured 20 miles out in order to give us time to extend the flaps / gear and run the Landing Gear Extension QRH. Since we were underweight yet still had the fuel to do so; I asked for a quick delaying turn to assure we had all checklists complete and the cabin was secured / ready. We made a successful landing on XXL; stopping with at least 8 - 9;000 ft. ahead of us. Thirty seconds out I had the FO make the Brace Call. At a slow speed the FO announced; Remain seated; remainseated;" and we came to a stop. Since the APU was running; I told the FO to secure the engines so that ARFF (Aircraft Rescue and Fire Fighting) could approach and inspect the aircraft. Operations stated that a large puddle of fluid was beneath the Number 1 engine; and fluid up near the left engine pylon. There were no fire indications so we stood by and waited for our tow to the gate.While the outcome was successful there was one issue I did not expect. After dropping the gear via the Landing Gear Extension Checklist; the "Blue to Do" prompted us to turn the G Eng Pump back on. I did not expect that. My first assumption was why should we do that when the system is completely empty; but we followed the procedure. A few seconds later the ECAM sounded with the original message we got at cruise. I had the FO turn the pump back off."


Synopsis: A320 flight crew reported loss of the green hydraulic system resulted in a diversion and precautionary landing.