A300
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Aircraft Equipment Problem Less Severe
Flight Crew Landed in Emergency Condition
Aircraft
Cruise flight at FL340 we received 'Hydraulic Fluid Loss' on the green system.  We followed the ECAM (Electronic Centralized Aircraft Monitor) procedures and confirmed the fluid loss on both the gauge on the overhead panel and ECAM 'Hydraulic' page.  Both indicators showed zero fluid.  After working through the ECAM procedures we ran both the HYD RSVR LO LEVEL and HYD SYS LO PR checklist in the red tabs.  This [is] where things got busy.  We had multiple procedures to review and brief:  Landing Speed Increments; Increased Landing Distance; Landing Gear Gravity Extension; Fuel Consumption Increased and Equipment Status with One or More Hydro Systems Inop.  We had approximateyl 40K of fuel and were within range of several airfields with long runways that could accommodate us.  We took our time and methodically worked our way though the multiple checklists.   FO (First Officer) did a great job of checklist management.  At one point we had both QRH's out just to  review the multiple additives for approach speed / landing distance and review of the L/G (Landing Gear) Gravity Extension checklist. Once we computed a landing speed / distance;  the multiple checklists and ECAM items were complete; we reached out to Dispatch and Maintenance Control via radio.  At this point we were approximately 1 hour from ZZZZ.  We agreed to continue to ZZZZ because the weather was VFR; light winds; and the airfield has 14;000 foot runway with multiple high speeds exits. I asked our Dispatcher to contact the Duty Officer and let him know about our status and advised Operations we planned to notify ATC.  Once we had a plan and were caught up on all the checklist we declared the emergency (ZZZ Center; I think) and requested direct to ZZZZ.  We requested vectors to XXR due to it's length and multiple high speeds.  Throughout the entire process we made every attempt to not rush.  Again; we had tons of gas and time.  Rushing would not have solved our problem; and would have only created more problems.  ATC vectored us to approx. a 40m final.  We briefed the nonstandard call-outs in the event of a go-around; as the gear would have to remain down.  Upon landing I was not comfortable attempting to make the highspeed exit without nosewheel steering.  We let Tower know we were unable to make the highspeed and would be stopping on the centerline of the runway.  They said that was fine and CFR (Crash Fire Rescue) was standing by.  Once CFR determined there were no injuries and the HZ (Hazmat) goods were secure the tug started to head our way.  We ran the After Landing checklist; but kept the lights on since we were still on the runway.  Runway XXR has a visible uphill gradient.  After setting the parking break we shut down the #1 engine and kept #2 running to ensure positive break pressure.  We kept the number 2 engine running until we were safely secured to the tug.  It was long; but uneventful tow back to the gate.  After block-in the mechanic said there was a visible drip of hydraulic fluid from the left pylon.   The green system quantity gauge on the overhead panel had come up to the top of the yellow arc at block in.
During cruise; the Captain noticed a slightly low and decreasing green hydraulic system level on the overhead panel. When we had last looked at it before the emergency; the level was on the border of the green and orange bands; but had been in the top that band during preflight. I mentioned that on previous flights; I'd seen the green system hydraulic level drop into the orange band; and after shutdown; the level indicated in the top hat again. At FL340 at .79 Mach; we received an ECAM (Electronic Centralized Aircraft Monitor) warning for Green Reservoir Low Level. We confirmed this on both the overhead indication and the ECAM hydraulic page; which showed the green system at zero/completely empty. So; we complied with the ECAM and turned off both green hydraulic pumps IAW (in accordance with) the ECAM direction; within 30 seconds from the warning and after confirming we were turning off the correct pumps. We continued with the directed QRH (Quick Reference Handbook): Green System Low Pressure; which told us to turn the brake/anti-skid to alternate/on; then to reference the Green Reservoir Low Level page in the QRH. As we ran this checklist; the autopilot 1 turned off; so we activated autopilot 2. This checklist had us turn off spoiler 6 and pitch feel 1. Spoiler 6 had already faulted (still showed retracted); but pitch feel 1 had remained engaged prior to us turning it off. This checklist concluded with us reviewing which other systems we had lost (auto brakes; nosewheel steering; normal gear extension; kruger flaps; and standby generator) and by telling us of the 5 knot flap; slat; and hook speed increase. It finally directed us to the Landing Speed Increment QRH page; which told us: we could do a 15/20 or 30/40 flaps landing (we elected 30/40 for slower speed with alternate braking system); add 5 to our Vref speed; and multiply our landing distance by 1.2. The Increased Landing Distance QRH page (2000' altitude) was the next checklist directed. We rounded up our weight to 280K pounds; noted the corrected Vref of 134 and calculated our landing distance 4946 (bare and dry; Rwy CC 5); added 540' (for 2000' above 2000'); subtracted 360' (for 30 degrees cooler than 38 degrees C); and multiplied the 1.2 landing factor to reach 6150 feet. Since this distance was for demonstrated max braking without autobrakes; we added another approximately 1500' (total distance estimated at 7500') because we did not intend to activate the alternate brakes as hard as physically possible (not knowing the pressure required with this alternate system and acknowledging we had long runways at our primary destination; ZZZZ). We then referenced; but did not execute the Landing Gear Gravity Extension QRH checklist; noting our inability to raise the gear afterward; our yaw/bank contingencies if the gear did not come down; and the visual confirmation required if down and locked indications were not received. Finally; we referenced the Fuel Consumption Increased QRH checklist and performed the calculation to determine our en route fuel burn with the spoiler 6/green system malfunction. We confirmed checklists were complete; validated no additional steps were required on the ECAM or system page; and talked about a big picture plan: yes; we would notify ATC; we would request a long straight-in; we would slow and configure very early to account for contingencies; we had plenty of gas; we had great weather; we were comfortable continuing to ZZZZ if Dispatch and Maintenance Control were happy with that course of action (2 long runways); and we would have non-standard Go-Around procedures because of the gear stuck down and slow slat/flap movement. We then used radio to talk to Operations and Dispatch in conference; agreed on continuing to ZZZZ; confirmed the pumps were off quickly after the ECAM warning; affirmed that we had zero pressure indicated; and thanked them for their help. Next; we contacted ZZZ Center; notified ATC; stated our intention to continue toZZZZ; provided the required information; including Dangerous Goods data; asked they give ZZZZ Center a heads up; and requested direct ZZZZ. ZZZ Center accommodated us and coordinated for us. ZZZZ Center and ZZZZ Terminal gave us vectors to a requested 30 mile straight in to XXR (longest runway despite long tow back to cargo ramp). We slowed and configured early incrementally IAW our plan; because of slow slats/flaps and manual gear extension. We talked that the jet might handle differently with the gear doors stuck open; no Kruger flaps; and spoiler 6 inoperative. We received our landing clearance from ZZZZ Tower on a discrete frequency; advised that we would try to make a high speed taxiway with differential braking to clear the runway; but that was the most we could accomplish with our inoperative systems. ZZZZ Tower advised us that fire rescue was waiting and that the security escort and tow were en route. We landed after a slight float; used maximum reversers; and stopped the jet on the centerline about 8000' down the runway. We were unable to make the final high speed taxiway; but came to a complete stop and set the parking brake. Fire confirmed nothing appeared hot and we had no apparent leaks. We relayed our DG (Dangerous Goods) data (classes and several of the UNs); and waited for the tow. While waiting; we shut down the left engine and cranked the APU (Auxiliary Power Unit); after shutdown of the left engine; the green hydraulic level returned to a low green indication (Below the top hat/above the orange band). The ECAM similarly showed a slightly low normal level. After shutdown of the left engine; fire rescue noted we had a slightly smoky engine; and some fluid dripping from the left engine. We attributed it to smoky Pratt and Whitney engines; and normal fuel/oil/water drips after shutdown. The tow arrived; we handed MX (Maintenance) the gear pins through the avionics compartment door; and we were towed back. During the tow; the green level continued to drop until it was in the orange band. After being chocked; applying ground power; and completing our normal shutdown procedures; MX greeted us and asked us what happened to cause the leak. They said there was definitely a hydraulic fluid leak in the left pylon; it was apparent from the ground and visible as we were being towed in. We advised them of the difference in fluid indication from in flight to after shutdown; completed the AML (Aircraft Maintenance Log) entry; debriefed with MX; called the Duty Officer; and left the ramp. The cause was only identifiable after maintenance action; but there was a hole in the green system hydraulic line; as well as a deterioration in line thickness and integrity caused by clamp friction. This was near the #3 flap fairing on the left pylon.This hydraulic malfunction is such an infrequent occurrence. It appeared to arise from normal chafing/wear and tear; due to numerous cycles. If it is an easy inspection item; this line could be examined during one of the periodic MX checks (A or C checks). If it is cumbersome; because it is so rare; it may be worth simply accepting the risk. One other possibility: I have experienced lower green hydraulic levels during flight on several previous legs. We would note green hydraulic levels in the low green band or in the orange band above the red dot; but the level would return to the top hat after shutdown. But on these flights; the level would just not drop low enough to trigger the ECAM warning. It may be worth specifying the acceptable green level drop in flight. For example; 'During flight; the green system hydraulic level may drop significantly. As long as the overhead indicator remains in the green band; no reporting or maintenance action is required. If the indicator drops into the orange band during flight; even if no ECAM warning is triggered; write up the green hydraulic system as an incremental leak may be developing.' This way; an inspection could be indicated before a serious loss of hydraulic fluid/alternate gear extension procedures are required.
Flight Crew flying A300 aircraft encountered hydraulic system failure in flight.