Widebody Transport
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft
Received a Level 1 'Emerg Power On' message while at cruise; FL380. We referenced the QRH; which states moving the Emergency Power Switch to OFF; and then to ARM; which we accomplished. The message remained. We monitored the Electrical System Synoptic for battery status; and created a plan in case the battery started depleting. Per the QRH; we had the option to deploy the ADG. During descent; the battery started losing charge; and we deployed the ADG. It came on-line without issues. Approx 2 minutes later; we received multiple messages on the EAD indicating an electrical system failure. The Capt lost his 3 MFDs; however I still had my 3 MFDs. I assumed PF duties; the Capt took over PM (Pilot Monitoring). We lost Radio #1; and maintained comm on Radio #2; where we notified ZZZ center of our electrical issue. No flight control issues were noted. No other system issues were noted. We [requested priority handling] passing through 10;000 ft. We received vectors for a visual approach to Runway XXR; with a 5NM final. Landing; roll-out; and taxi were uneventful. Electrical system malfunction.A systems problem; that I don't know how it could be prevented. The ADG worked as advertised; and we were prepared for the loss of some systems if the ADG became the sole source of electrical power.
During cruise at FL380 we received a level one alert 'EMERG PWR ON'. We went to the QRH which told us to cycle the Emergency power switch to see if [the] alert would go away; which it did not. It said to monitor battery power and if needed to deploy the ADG. Power stayed steady at 26 for the battery for 35-40 minutes. Then [the] battery started to deplete and the decision was made to deploy the ADG while we were descending on the arrival. When ADG was deployed Captain's instruments and radio went away and control was given to the F/O and radio 2 was used. We [advised ATC] and were descended to 2;000 ft. and became visual with the airfield. My HUD was working and I decided to take the aircraft on base leg in case any other unforeseen problems arose. Normal landing and [priority handling] was called off after landing rollout.Battery system and emergency power malfunction. ADG deployment reduced systems available but was handled according to emergency procedures.I am not sure if this could have been avoided as far as the flight deck was concerned. The [incident] was handled according to the QRH and flown to an uneventful finish.
Flight Crew reported battery charging and emergency power systems malfunctioned; requiring the deployment of the air driven generator and a precautionary landing.