Date: 202111
Local time of day: 1801-2400
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
Aircraft component: Engine Control
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Physiological - Other; Troubleshooting
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant; Person Flight Crew
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During cruise at FL310 and approximately one hour into the flight; we got an ECAM for auto throttle and auto pilot off. We followed company protocol and completed the ECAM actions. Both the auto throttles and auto pilot were restored. About 5 minutes later; we received a call from the Lead Flight Attendant stating that they could smell a strong acrid smell in the mid cabin area around row 26. It lasted for about 5 minutes; then dissipated. The crew explained they had symptoms of throat discomfort and headache. We followed the QRH for Aircraft Odor; notified Dispatch; Maintenance and Operations. Approximately 30 minutes later; we got the same exact ECAM for auto throttle and auto pilot off. Following the ECAM actions; both auto throttles and autopilot were restored and continued to work for the duration of the flight. After landing; the Flight Attendants told us they could smell the same odor again for a few minutes; then dissipated. We submitted the Odor form; made log book entries and contacted the airport medic to evaluate the flight attendants. No passengers made any complaints that I am aware of. The Flight Attendants went to the hospital with symptoms of throat discomfort; watery eyes and headache. It's possible that the auto throttle and autopilot disengaged due to an EEC (Electronic Engine Control) computer failure which may have triggered a short burning or odor event; passing through the packs into the cabin. The Mechanics told us they were going to replace the EEC computer. The ECAM and the odor even happened within 5 minutes of each other but it was unclear whether or not this correlation was causation or not. Preventative maintenance would be my suggestion. We are experiencing multiple mechanical issues with our Airbus fleet. My experience is that we wait for the problems to happen. We should be more proactive in capturing maintenance malfunctions before they occur. There is maintenance software than can help with this.


Second narrative: Cruising at FL310; approximately an hour into the flight; ECAM AUTO FLT AP OFF and A/THR OFF.  We performed the ECAM actions and were able to reengage the Autopilot and Auto thrust shortly after.  Within 5 minutes of the ECAM; the Flight Attendants called and complained of an acrid smell from rows 24 and aft.  The timing of the 2 events led us to believe they were somehow related; and the Captain asked the Flight Attendants to call back within 5 minutes to report on the acrid smell. We also followed up with the QRH Odor/Toxic Substance/Volatile Liquid.  When they called back the smell had dissipated and that they were OK to continue to ZZZ1.  We followed up with contacting Operations and Maintenance Control when time permitted.  Within :30 min of the first event we had a second repeated event of the AUTO FLT AP OFF and A/THR OFF.  Again we performed ECAM actions; and were able to restore the affected systems back to normal; and there was no odor event in the cabin associated with the second event.  We landed in ZZZ1; and the flight attendants again informed us of a second odor event as we landed and that it also dissipated quickly.  We arrived at gate and then FA (Flight Attendant) (#1) informed us of that FA #2; FA #3; and FA #4 had throat discomfort and headaches.  We called for Medical assistance at that time and all of the FA's decided to go to hospital for further evaluation.  None of the passengers made any complaints; as I understand.  The AUTO FLT AP OFF and A/THR OFF event caused the odor event in the cabin due to the partial failure of the #1 eng EEC (Electronic Engine Control).


Synopsis: A321 flight crew reported flight attendant notification of an 'acrid smell' which dissipated and reoccurred. Flight continued to destination where Medical and Maintenance were requested.