Date: 201306
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Fuel Tank
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Passenger
When detected: In-flight
Result: Aircraft Aircraft Damaged; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; Flight Crew Returned To Gate; General Declared Emergency
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During climb; we received a call from another carrier jumpseater in the back. He advised us that fuel was venting out near the wingtip of the right wing; apparently from the underside of the wing. We advised ATC that we would be air returning and declared an emergency. We informed them to advise emergency vehicles that we were leaking fuel from the right side and would land; come to a stop; and have them inspect the plane prior to taxi to ensure we wouldn't be spilling fuel across the airport or around the gate area; though we expected that the fuel would stop leaking once we landed (since we suspected it was coming from the vent system). As we maneuvered; the jumpseater advised us that the venting was stopping and starting; though diminishing in intensity. It ultimately stopped. A cockpit jumpseater assisted us with the FMS and backing us up. He also helped with looking up emergency checklists and handing them to us while we handled radios and the aircraft. Passengers were advised of the situation and we accomplished an overweight landing. The plane was inspected and found to not be leaking fuel any longer. We taxied to the gate and deplaned. Maintenance found that a flapper valve located by the fuel vent had detached and that was allowing fuel to enter the vent system. There was some residual fuel on the underside of the wing and back on the flaps. We monitored brake temperature throughout the taxi-in and requested a shortened taxi route.-I thought this event went quite well. There was good coordination between the front and back. We considered landing Flaps 22; since our approach speed was 3 knots from Vfe (45); but opted out of that considering the longer landing distance and already being overweight. There was also a discussion of not using reversers with a potential fuel leak; but opted to deploy them; considering that the risk was negligible; considering that the leaking was reported to have stopped by the jumpseater; was out near the wingtip; and that stopping the airplane in it's heavier than normal state was critical. We opted to not use them outside of idle; unless conditions seemed to dictate otherwise and to ensure they were closed by 60 knots.


Second narrative: I learned that during an emergency allocation of duties is paramount. Not only was the high workload distributed among the crew working the flight but also to the jumpseater. All of the crew working together helps to insure that tasks do not go unattended.


Synopsis: An EMB-145 flight crew returned to their departure airport for maintenance when advised by a deadheading pilot that fuel was leaking; apparently from a tank vent on the right wing tip.