A300
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC complied w / Automation / Advisory; General Declared Emergency; General Maintenance Action
Aircraft; Procedure
During preflight I noted that the green system hydraulics were very low; almost into the yellow or amber band. I let Maintenance know we needed to be serviced. He stated the level had been good when Maintenance had last checked it at the termination of the previous flight. I asked when they were servicing the green system if they found any leaked hydraulic fluid; and Maintenance replied in the negative. This seemed a little odd; and indicated either a possible gauge problem or a hidden leak. During descent we received an ECAM warning for low green hydraulic system fluid quantity. The overhead quantity gauge pointer was at the 'red dot.' Per the ECAM we turned off the green hydraulic pumps. Due to the fact we would need some extra time on final approach to manually extend the landing gear; plus the requirement to stop on the runway and be towed in from there; we declared an emergency with ATC. After completing all related ECAM and QRH procedures; we landed uneventfully. After extending the gear; the green hydraulic quantity recovered to about the 12 o'clock position on the quantity gauge. By the time we arrived in the gate after tow-in; the quantity had dropped almost to the yellow band again. On post flight Maintenance stated they found a leak in the Number 1 Engine pylon. Perhaps more in-depth troubleshooting during the preflight would have revealed the hydraulic leak there.
A300 Captain reports loss of Green Hydraulic System fluid during descent for landing. The fluid level had indicated low prior to departure and was serviced. An emergency is declared and a normal landing ensues after gravity gear extension.