Narrative:

During the last phase of climb and about to reach FL340; the aircraft passes through a zone of light turbulence (without representing any special consideration for it) and at that same time the ap (automatic pilot and a/thr (automatic thrust) systems disconnected by itself without any apparent reason; following this situation the screens on the cockpit experienced a 'black out' for about 1 or 2 seconds (a similar situation could be observed with a change of electrical power when using the external power unit when on ground) afterwards all navigations capabilities on the aircraft were lost and the ewd (ECAM warning display) only showed the following ecams; automatic ftl a/thr off and engine thrust locked (thr levers.....move)the capt (pilot monitoring) at that time; calls out for a positive exchange of controls as established by the company policies and sops 'I have controls'... And then commands the start of 'ECAM actions'. We follow the ECAM and made a quick evaluation of the general condition of the aircraft discovering the following:1) a cross check of the flight instruments was made looking for indications that could lead us to suspect of an abnormal V alpha prot or unreliable speed indication without finding any differences in relation with airspeed or altitudes indications in between the primary and the standby flight instruments.2) we were not able to re-connect the ap (automatic pilot) and a/thr (automatic thrust) systems by any means available.3) both pfd (primary flight displays) showed indications that lead to the loss of flight protections (altitude law/direct law).4) both nd (navigation displays) neither showed the map route nor any other navigation references that help us to establish a good geographical position. Both nd remained with the arc selection.5) both mcdu's (multifunction control display units) were frozen and did not accept any inputs.6) the behavior of the aircraft in flight regarding handling was really sensitive to flight control inputs on hand flying but it remained within positive control for pilots.the capt. (Now acting as pilot flying) contact ARTCC and informs them about the loss of the automation and navigation systems of the aircraft and made a request to leave rvsm (reduced vertical separation minima) while continuing the flight to destination its evaluated and the possibility of diverting. ARTCC maintain the flight at FL340 for few minutes and ask if we were able to fly to [a nearby airport]; our response is that it is not possible due to the lack of navigation systems; we then received a vector to fly and a clearance to descend to FL280. While this is happening we made a new cross check on flight instruments looking for differences on indications and we pull down the magnetic compass for a better references in flight without finding variations on indications.at the same time we continue with the coordination and task sharing for the flight crew so the first officer (now acting as pilot monitoring) refers; finds and start the procedures stablished by the QRH and flight crew operations manual regarding the different scenarios that were stablished after the first evaluations made at the start of the failure and considering the following procedures: (presented in this report with no specific order of application)- ir alignment in att mode - navigation ir disagree - navigation adr disagree - adr 1+2+3 fault - abnormal V alpha prot - unreliable speed indication - alternate and direct law - landing assessment - fuel calculationsuddenly the pfd (primary flight display) and nd (navigation display) of both captain and first officer came back to a 'normal' state of operation but ap (autopilot) and a/thr (automatic thrust) did not respond again to any activation attempts; seconds after; the failure appeared again and pfd and nd returned to its previous failure state described before.at this point we were transferred to [adjacent] ARTCC and we transmit our decision to divert; this decision was made afteras a crew; captain and first officer determined that the aircraft status in this condition was not reliable for the continuity of the flight; representing an undesirable state; situation that affected the safety of the passengers and flight crew aboard the aircraft. We receive a vector to fly north and minutes after being established on that heading we were transfer back to [original] ARTCC. A moment before contacting ARTCC the aircraft recovered by itself its normal flight conditions. All navigation and automation systems were able to recover for flight.ARTCC inquired us about the status of the flight and the aircraft condition besides a general description of what was happening; we advised ATC that the navigations and automation systems were not operating normally due to intermittent failures that occurred minutes before and the failures did not make the aircraft reliable for flight; and we stated that this conditions represented a risk for the possible loss of flight protections of the aircraft that could lead to undesirable condition during landing (thinking about a direct law). ARTCC gave us clearance to flight direct to ZZZ; we then informed of our intentions to use runway 28R at ZZZ witch is the longest runway available at the airport and requested the presence of the emergency crew and equipment of the airport. At that moment we made a new full revision of all procedures described regarding the failures that could have affected us minutes before in order to have a better understanding of what could happen if the failure came back again or by any means what could happened if we had a much worst situation during the remaining of the flight and landing attempt; after that; we ask for vectors to the northeast in order to burn some of the remaining fuel so we were able to avoid an overweight landing at ZZZ.we must remark that we made all necessary coordination's and communicate all our requirements at all times with ATC; flight attendants; stations and briefing to passengers. The flight crew CRM performed with an excellent communication level and understanding; always with a full respect and proactivity in order to resolve the situations that we faced during flight until our landing at ZZZ; also; all the decision were made in conjunction and with a full understanding of its consequences. The final approach and landing were made in normal conditions; the failures at those points never came back again; but we were on alert in case any failure appeared once again.

Related reports:

Google
 

Original NASA ASRS Text

Title: A320 Captain reported experiencing an electrical anomaly at FL340 resulting in loss of autopilot and autothrust along with Navigation Display information and frozen MCDUs. PFDs indicated Alternate Law. ATC is advised and the flight diverted to a suitable alternate airport.

Narrative: During the last phase of climb and about to reach FL340; the aircraft passes through a zone of light turbulence (without representing any special consideration for it) and at that same time the AP (AUTO PILOT and A/THR (AUTO THRUST) systems disconnected by itself without any apparent reason; following this situation the screens on the cockpit experienced a 'BLACK OUT' for about 1 or 2 seconds (A similar situation could be observed with a change of electrical power when using the external power unit when on ground) afterwards ALL navigations capabilities on the aircraft were lost and the EWD (ECAM WARNING DISPLAY) only showed the following ECAMS; AUTO FTL A/THR OFF and ENG THRUST LOCKED (THR LEVERS.....MOVE)The Capt (PILOT MONITORING) at that time; calls out for a positive exchange of controls as established by the company policies and SOPs 'I HAVE CONTROLS'... and then commands the start of 'ECAM ACTIONS'. We follow the ECAM and made a quick evaluation of the general condition of the aircraft discovering the following:1) A cross check of the flight instruments was made looking for indications that could lead us to suspect of an ABNORMAL V ALPHA PROT or UNRELIABLE SPEED INDICATION without finding any differences in relation with airspeed or altitudes indications in between the primary and the standby flight instruments.2) We were not able to re-connect the AP (AUTO PILOT) and A/THR (AUTO THRUST) systems by any means available.3) Both PFD (PRIMARY FLIGHT DISPLAYS) showed indications that lead to the loss of flight protections (ALT LAW/DIRECT LAW).4) Both ND (NAVIGATION DISPLAYS) neither showed the map route nor any other navigation references that help us to establish a good geographical position. Both ND remained with the ARC selection.5) Both MCDU's (MULTIFUNCTION CONTROL DISPLAY UNITS) were frozen and did not accept any inputs.6) The behavior of the aircraft in flight regarding handling was really sensitive to flight control inputs on hand flying but it remained within positive control for pilots.The Capt. (now acting as PILOT FLYING) contact ARTCC and informs them about the loss of the automation and navigation systems of the aircraft and made a request to leave RVSM (REDUCED VERTICAL SEPARATION MINIMA) while continuing the flight to destination its evaluated and the possibility of diverting. ARTCC maintain the flight at FL340 for few minutes and ask if we were able to fly to [a nearby airport]; our response is that it is not possible due to the lack of navigation systems; we then received a vector to fly and a clearance to descend to FL280. While this is happening we made a new Cross Check on flight instruments looking for differences on indications and we pull down the magnetic compass for a better references in flight without finding variations on indications.At the same time we continue with the coordination and task sharing for the flight crew so the First Officer (Now acting as PILOT MONITORING) refers; finds and start the procedures stablished by the QRH and Flight Crew Operations Manual regarding the different scenarios that were stablished after the first evaluations made at the start of the failure and considering the following procedures: (presented in this report with no specific order of application)- IR ALIGNMENT IN ATT MODE - NAV IR DISAGREE - NAV ADR DISAGREE - ADR 1+2+3 FAULT - ABNORMAL V ALPHA PROT - UNRELIABLE SPEED INDICATION - ALTERNATE AND DIRECT LAW - LANDING ASSESSMENT - FUEL CALCULATIONSuddenly the PFD (PRIMARY FLIGHT DISPLAY) and ND (NAVIGATION DISPLAY) of both Captain and First Officer came back to a 'NORMAL' state of operation but AP (AUTOPILOT) and A/THR (AUTO THRUST) did not respond again to any activation attempts; seconds after; the failure appeared again and PFD and ND returned to its previous failure state described before.At this point we were transferred to [adjacent] ARTCC and we transmit our decision to divert; this decision was made afteras a CREW; Captain and First Officer determined that the aircraft status in this condition was not reliable for the continuity of the flight; representing an undesirable state; situation that affected the safety of the passengers and flight crew aboard the aircraft. We receive a vector to fly north and minutes after being established on that heading we were transfer back to [original] ARTCC. A moment before contacting ARTCC the aircraft recovered by itself its normal flight conditions. All navigation and automation systems were able to recover for flight.ARTCC inquired us about the status of the flight and the aircraft condition besides a general description of what was happening; We advised ATC that the navigations and automation systems were not operating normally due to intermittent failures that occurred minutes before and the failures did not make the aircraft reliable for flight; and we stated that this conditions represented a risk for the possible loss of flight protections of the aircraft that could lead to undesirable condition during landing (Thinking about a DIRECT LAW). ARTCC gave us clearance to flight direct to ZZZ; we then informed of our intentions to use RWY 28R at ZZZ witch is the longest runway available at the airport and requested the presence of the Emergency crew and equipment of the airport. At that moment we made a new full revision of all procedures described regarding the failures that could have affected us minutes before in order to have a better understanding of what could happen if the failure came back again or by any means what could happened if we had a much worst situation during the remaining of the flight and landing attempt; after that; we ask for vectors to the Northeast in order to burn some of the remaining fuel so we were able to avoid an overweight landing at ZZZ.We must remark that we made all necessary coordination's and communicate all our requirements at all times with ATC; FLIGHT ATTENDANTS; STATIONS and BRIEFING TO PASSENGERS. The flight Crew CRM performed with an excellent communication level and understanding; always with a full respect and proactivity in order to resolve the situations that we faced during flight until our landing at ZZZ; also; all the decision were made in conjunction and with a full understanding of its consequences. The final approach and landing were made in normal conditions; the failures at those points never came back again; but we were on alert in case any failure appeared once again.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.