Date: 201502
Local time of day: 1201-1800
Location: LAS.Airport, NV
Light: Daylight
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B LAS
ATC / advisory: TRACON L30
Aircraft component: Altimeter
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Situational Awareness
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: I was the Pilot Flying (PF) we were cleared to descend via the KEPEC 3 Arrival into LAS RWY 25L. I set 8000 feet on the FCU which is the altitude to set for the arrival; I started the descent using managed descent with a thorough briefing and checking the ND and MCDU prior; with my First Officer (FO) backing me up. There was a crossing restriction to cross KEPEC at 13;000 feet. All of a sudden my FO being the Pilot Monitoring (PM) alerted me to my altitude which at the time was 12;700 I was below 13;000 feet and immediately set 13;000 feet selected open climb to climb back up to the 13;000 feet. When I went below the 13;000 feet it was under 4 miles before KEPEC. At the time ATC asked as to verify our altitude; we then realized our altimeter setting was wrong. It was supposed to be 29.94 and we had set 30.10 from the departure airport. We told ATC about the wrong altimeter setting and apologized. They said it was okay. Always double check your arrival with the ND and MCDU let both Pilots check the work; and monitor always. Even if it means taking over with other modes or even disconnect the autopilot if you have to; Always slow down never rush Monitor; Monitor. Make sure your altimeter setting is correct.


Second narrative: ATC: 'Descend via the KEPEC 3 Arrival'. Bottom altitude of 8;000 feet was set by Pilot Flying (PF) Captain (CA). '8;000 blue'. The FMGC did not recognize the altitude constraints on the arrival. KEPEC; IPUMY; NIPZO; etc. 'Magenta 13;000 feet' or 'ALT CSTR' were not presented on the FMA for KEPEC; our first hard altitude. Between SKEBR and KEPEC the aircraft continued its descent through 13;000 feet on its way to 8;000 feet even in managed decent with the altitude constraints programmed. At 12;700 feet both the captain and I noticed we were low and the captain (PF) immediately applied corrective action as we were being made aware of our deviation by Vegas Approach. Approach said there was no conflict and no action was needed by the flight crew.I believe this is a software issue in our A319 aircraft. I have seen this 'disregarding' of altitude constraints by a 319 before and caught it prior to the aircraft busting an altitude in the managed altitude mode.


Synopsis: A319 flight crew reports descending below the KEPEC crossing restriction on the KEPEC3 arrival to LAS. The aircraft was descending in managed descent but the FMGC apparently did not recognize the restrictions; displaying them in blue rather than magenta. An altimeter setting error was also involved.