Flight Crew Air Transport Pilot (ATP)
Confusion; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance
Flight Crew Became Reoriented; Flight Crew Returned To Clearance; Flight Crew FLC Overrode Automation
Aircraft; Human Factors; Environment - Non Weather Related
We were cleared to descend on the HYDRR 1 Arrival to Phoenix via the 25L Transition. We were then given a runway change to 26 due to an anticipated Runway Inspection (RWY 25R was closed). Just prior to CHAVO waypoint; the airplane FMS Mode went from PATH to Vertical Speed (pink) and the airplane pitched over to a greater than 3;000 FPM descent. Even though the VNAV mode was pink; the airplane flew through the 9;000 foot restriction at CHAVO. The Captain alerted the First Officer verbally (flying pilot) that the FMS/Auto Pilot had basically failed and to hand fly the airplane and return to 9;000 feet. The plane got as low as 8;500 to 8;600 feet. We returned promptly to 9;000 feet.English is not the 'home' language for the First Officer. He was surprised (zone of confusion) when I told him to hand fly the airplane and get the FMS/Autopilot off. Thus; the reason for the very quick 500 feet altitude bust. It should be noted; that the Phoenix Approach Controller never told us to check our altitude as we were over an area of high terrain.
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EMB-175 flight crew reported descending through an altitude on the arrival when the FMS/autopilot failed to level off after an aggressive descent rate.