Date: 201512
Local time of day: 0601-1200
Location: D10.TRACON, TX
Flight conditions: VMC
Aircraft: Airbus Industrie Undifferentiated or Other Model
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E D10
Aircraft component: FMS/FMC
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Undershoot; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Human Factors; Aircraft
Primary problem: Aircraft

Narrative: Strange readouts on the #1 and #2 MCDU's. For instance; the #1 MCDU and #2 MCDU were showing the same altitude and speed targets at crossing fixes; but #1 showed amber while #2 showed magenta. First Officer (FO) was by far the more experienced in the Airbus and was flying. Cleared out of FL250 direct KLNDR and to descend via the rest of the KLNDR2. 11;000 set in the altitude selector. Managed descent. Although both Primary Flight Displays (PFD) were showing on glide path (green dot); it was obvious that the aircraft would be too high at WARDZ. FO intervened with speed brakes; and neither of us understood why the aircraft was responding by adding power [Crew Resource Management]. The altitude restriction was between 11;000 feet and 13;000 feet. Crossed at 13;520 feet.Must be an Airbus idiosyncrasy. I only have around 40 hours P.I.C. Do not recall ever seeing a zig zag arrow during any part of the arrival (arrow that indicates beginning of glide path). Aircraft had ALTCRZ (something I regularly check for) when at cruise altitude (FL320) so it must have been descent mode at the proper time.


Second narrative: During the arrival; we both reviewed the procedure and as pilot flying I briefed the arrival and approach. Early in the arrival we were given vectors/speeds/descents; and an eventual direct to KLNDR (or possibly a fix further into the arrival) with intermediate descents. During the arrival; we noted that the Navigational Displays (ND) on the First Officers (FO) side Pilot Flying (PF) indicated an amber circle at a couple of the points (high indication) but on the Captains (CA) side; the ND was magenta (on altitude). En route to fix when given the 11;000 crossing restriction (managed descent/expecting 'More Drag') the programed speed was attained; the power came up; and we noted that we would still be high. I intervened with selected speed; open descent; and speed brakes. We still were maybe 400-500 feet too high. ATC gave us a further descent and made no mention of the error.I've not seen this issue before so quite honestly; the best suggestion is review [Crew Resource Management]...only by intervention were we able to avoid an even larger excursion.


Synopsis: Airbus flight crew reported they failed to make a crossing restriction when MCDU's 1 and 2 disagreed on projected vertical path performance.