MD-83
Flight Crew Air Transport Pilot (ATP)
Confusion; Communication Breakdown; Situational Awareness
Aircraft Equipment Problem Critical; Deviation - Altitude Crossing Restriction Not Met; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Flight Crew Became Reoriented; Flight Crew FLC Overrode Automation; Flight Crew Returned To Clearance
Aircraft; Human Factors; Procedure
On STAR to PHX cleared to descend via the EGUL RNAV STAR; landing Runway 26. The Captain was flying pilot and selected VNAV on the FMS aircraft. VNAV made all crossings prior to VNMOM then suddenly could not keep up with the steep descent needed from HOMRR to VNMOM. We both noticed this and the Captain took corrective action but at VNMOM we were still 10 KTS fast and 2;500 high. Upon noticing that correction was needed the Captain got out of VNAV and made all the other restrictions in VS mode. No indication of any conflict with other aircraft.It is IMPORTANT TO GAUGE descent rates between points on arrival; we had four miles to lose 5;000 FT if we crossed HOMRR at 16;000 (chart says HOMRR 16;000 or below).
No substantive additional information was included in the secondary narrative.
An MD-83 fLight crew failed to comply with the crossing restriction at VNNOM when flying the EGUL RNAV STAR to PHX.