A319 Pilot reported loss of both ELACs while at cruise and assisted the Flight Crew in handling the situation. The aircraft landed safely at destination airport.

Narrative

During cruise flight; ELAC [Elevator Aileron Computer System] 1 and 2 failed over [Location]. I was a dead heading pilot sitting in [seat] X. I was called to the cockpit by the Captain whom I flew with during the course of this 4 day trip. In addition; I was PM (Pilot Monitoring) on Aircraft X; ZZZ-ZZZZ. I have flown the Airbus [for many years] for various carriers. In addition [to] being a Line Pilot; Captain and First Officer; I have also been an instructor [for] Airbus. The Captain felt that I could be of use to his very well qualified crew as a third member in the cockpit. Let me be clear to say that the First Officer; the PF (Pilot Flying); was a former [other Airline] pilot who had thousands of hours of experience. The Captain had well over 5;000 hours in the seat. My role in the event was support alone. When the FA (Flight Attendant) came back to inform me that the Captain requested my presence in the flight deck; I knew what that meant. I grabbed my IPad and proceeded to the cockpit. Once inside; the ECAM (Electronic Centralized Aircraft Monitor) told me everything system wise and the PFD indicated that the crew was in Alternate Law. The FO (First Officer) was hand flying the aircraft and we were at FL260. I took my place in the jump seat and asked how I could be of assistance. The Captain passed the radio comms to me while the FO flew. It's one thing to fly around at 5;000 ft. while demonstrating Alternate Law and it's quite another to be fully immersed in an aircraft that is making uncommanded movements via pitch; be in turbulence at FL260; all while speaking with ZZZZ Air Traffic Controllers. The PF was doing a great job. I took Com 1. The Captain was trying the [to] contact Dispatch/Maintenance control via the crew phone but was having trouble with 2 way cutting out. I went to the FOM and provided him with ARINC (Commercial Radio) freq to call ZZZ1 radio. While he was doing that; I was speaking with ATC; coordinating descent and making inputs to the FCU (Fuel Control Unit). Again; the FO was very actively flying the aircraft and doing a great job. I then focused on systems. The overhead indications were 'lights out' which ordinarily would mean the flight control computers were working. Except the ECAM said they weren't. I then pushed the F/CTL page and all indications were green. Again; would look normal. Except something was happening because clearly we were in alternate law. I researched QRH for a reset but it was for On Ground Only. There was no reset. I then looked in Comply AOM for information. I also referenced the QRH within Comply. The Captain was very busy; the FO was busy flying; I am doing the radios and referencing manuals. In addition; my role is simply support so at appropriate times I informed the CA (Captain)/FO about what they had systems wise and what was going to happen systems and performance wise when we degraded to Direct law. Referred to the NNP (Non Normal Performance) pages of QRH; did their landing distance computation; and also reminded the crew that when determining Vapp to make corrections off of flaps full speed before selecting flaps 3. Captain requested backup for non routine landing considerations. At all times he was in command and my role was to have the appropriate manuals out and ready for when he requested. This crew was also dealing with the normal communication issues facing every crew on every flight. Task saturation; communication barriers; airspace closures related to military airspace requiring the crew to NOT be able to proceed directly to the divert airport; dark and turbulent versus dark and stormy; communication barriers with ATC; and balancing the need to follow the ECAM with the need to reference other manuals. In addition; at least 2 times the cockpit crew was interrupted by communication not from the number 1 FA (Flight Attendant) but from the rear flight attendants. They meant well but their concerns weren't relevant and not helpful. This crew did a great jobmanaging the serious issues and I was happy to assist. On final I did suggest configuring to flaps 3; on speed; before gear down command since the plane would be trimmed already making it easier on the FO to fly. He did a great job.Please put the ARINC freq map back in the QRH. Please tab the QRH although I tab mine myself.