AN A319 FLT CREW EXPERIENCED ECAM WARNING RES OVERHEAT GREEN SYS. THEY DECLARED AN EMERGENCY; CONSULTED WITH DISPATCH AND DECIDED TO DIVERT TO AN APPROPRIATE AIRPORT.

Narrative

ON CLBOUT WITH CAPT FLYING AND AUTOPLT ENGAGED GOING THROUGH APPROX FL210; WE RECEIVED AN ECAM INDICATING A RESERVOIR OVERHEAT IN OUR GREEN HYD SYS. THE CAPT TOOK THE RADIOS AND CONTINUED TO FLY WHILE I RAN THE APPROPRIATE CHKLISTS. THE CAPT DECLARED AN EMER WITH ZZZ CTR AND GOT A CLRNC TO ZZZ. WE NOTIFIED DISPATCH OF OUR SITUATION AND I GOT OUT MY FLT MANUAL AND LOOKED AT THE CHKLIST TO MAKE SURE WE HAD NOT MISSED ANYTHING. WE MADE AN ASSESSMENT OF WHAT SYS WERE AFFECTED AND HOW IT WOULD IMPACT OUR APCH AND LNDG. WE DETERMINED WE WOULD HAVE TO DO A MANUAL EXTENSION OF THE GEAR AND WOULD HAVE NO NOSEWHEEL STEERING UPON LNDG AND WOULD PROBABLY NOT BE ABLE TO CLR THE RWY. WE NOTIFIED ATC OF THIS. DISPATCH SENT A MESSAGE SAYING HE WOULD PREFER WE GO TO ZZZ1 AND WE AGREED THAT ZZZ1 WAS ACCEPTABLE TO US; SO WE NOTIFIED ATC AND RECEIVED A CLRNC TO ZZZ1. AFTER DISCUSSING THE ACFT STATUS; THE CAPT AND I DECIDED THAT SINCE I HAVE 10 YRS EXPERIENCE AND 7000 HRS IN TYPE AND CAPT HAD 1 YR ON THE ACFT; THAT IN THE INTEREST OF SAFETY I WOULD FLY THE APCH AND LNDG. CAPT ASKED IF I WAS COMFORTABLE WITH THIS AND I SAID THAT I ABSOLUTELY WAS. AT APPROX 6000 FT ON THE DSCNT; THE TEMP IN THE HYD SYS WENT BELOW THE OVERHEAT THRESHOLD AND IN COMPLIANCE WITH THE CHKLIST WE WERE ABLE TO RECOVER THE SYS. FROM THIS POINT IT BECAME A NORMAL APCH AND LNDG AND WE NOTIFIED ATC; BUT LET THEM KNOW THAT IF THE OVERHEAT RETURNED WE WOULD ONCE AGAIN BE UNABLE TO CLR THE RWY. APCH AND LNDG WERE UNEVENTFUL TO RWY AT ZZZ1. ONE ITEM I FAILED TO MENTION WAS THAT THE CAPT DID CALL THE FLT ATTENDANTS AND TELL THEM WHAT WAS GOING ON. CAPT ALSO ISSUED A CABIN ADVISORY; WHICH I FELT WAS APPROPRIATE. ATC WAS VERY HELPFUL THROUGHOUT THE ENTIRE INCIDENT.