Date: 201711
Local time of day: 0601-1200
Location: DFW.Airport, TX
Flight conditions: VMC
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E ZFW
ATC / advisory: Center ZFW
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Troubleshooting; Human-Machine Interface; Distraction
Second reporter function: Captain
Anomaly: Aircraft Equipment Problem Critical; Deviation - Altitude Overshoot; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Contributing factors: Aircraft; Human Factors; Manuals; Procedure
Primary problem: Aircraft

Narrative: While descending into DFW on the BRDJE3 we missed a crossing restriction at TUSLE. It was the Captain's leg so I was the Pilot Monitoring (PM). We were at 34;000 feet and given a descent to 24;000 feet. I set the altitude in the window and the Captain pushed for DES mode and the airplane started down. Not long after starting our descent we got an AUTO FLIGHT FCU 1 Fault ECAM and the Captain then pulled for open descent. The Captain said he'll fly the airplane and I run the ECAM. I ran the ECAM then got out the QRH.While I was looking in the QRH; ATC told us descend via the arrival. I can't remember who set 11;000 feet; one of us did; but we both verified it. I went back heads down and continued with the checklist. There was a reset in the checklist; which I ran; and it cleared the fault. ECAM complete; screens normal. The Captain then asked for me to send a Maintenance Report Message (MRM). I pulled up the page; typed in the ECAM message in the comment section the first time and it came back in error. I then tried [again] on the next one along with a description again in the comment section. I made a few typing errors and I tried to backspace; but if you hit backspace more than twice it erases the entire line. Pretty annoying and I kept fumbling around with it. The Captain was watching me and giving me his input on how to do it also; so that added to the confusion. I haven't done too many [reports] before and both the Captain and I thought it would be just like sending in a write up along with a location. This all took about 4-5 minutes and the next thing I know the Captain is talking to ATC and we are climbing back up to 17;000 feet. The whole time we were in open descent and we weren't even close to where we were supposed to be; 8;000 feet low. ATC said no problem; make the next crossing at 17;000 feet then continue via. Continued without further incident.


Second narrative: While flying at FL360 we were descended to FL320. Then given pilot's discretion to FL240. A few minutes later we were told to descend now to FL240. I pushed for managed descent. Immediately an ECAM alert came up of FCU 1 inoperative. The First Officer asked if I wanted the QRH and I said no for him to run the checklist.After passing FL290 we encountered light continuous turbulence. I pulled the altitude knob for open decent to expedite through the bumps; turned on the seatbelt sign; and made a quick announcement to the passengers. The First Officer ran the checklist in the QRH and reset the circuit breaker. The ECAM was complete and screens normal. I told the first officer to send a Maintenance Report Message (MRM) for the resetting of the circuit breaker. The First Officer typed in a message and hit send. It came back with an error. ATC called and assigned us to descend via the BRDJE3 arrival; but maintain 280 knots. The First Officer set 11;000 in the window and I verified it. I set 280 on the speed. Neither one of us verified the FMA. We both went heads down to the ACARS to fix the MRM and fixated on the MRM. We were trying to determine how to put in the circuit breaker location to the top line.As I saw the altitude going through FL180 I looked and set the altimeter. Then I realized we were well below the crossing altitudes at TUSLE of FL300-FL240. The First Officer was still trying to get the message out on ACARS. I leveled off at 17;000 and I notified ATC. ATC said to climb and maintain 17;000 until rejoining the arrival. We did and the rest of the flight was uneventful.


Synopsis: A319 flight crew reported altitude deviation due to distraction from flying duties during arrival.