Recent analyses have demonstrated that on A330 aircraft, if the aircraft is in EMER ELEC configuration and single hydraulic Engine Driven Pump (EDP) operation, the following may cause the loss of the emergency generator: In turbulent weather conditions during approach, the increased hydraulic demand from the flight control system and the emergency generator may not be satisfied when the flight crew sets the​ pb-sw to ON. As a result, the priority valve may close, and cause the loss of the emergency generator.Therefore, the batteries become the only source that can supply power to the aircraft electrical network.

To supply the aircraft with sufficient green hydraulic power and prevent closure of the priority valve in case of single EDP operation, the flight crew must manually extend the Ram Air Turbine (RAT) before they set the​ pb-sw to ON, when they apply the ECAM procedure.Due to the extension of the RAT, the speed must not be less than 140 kt. Therefore, the flight crew must ensure that the approach speed (VAPP) is at least 140 kt and confirm the corresponding landing distance.