EMB ERJ 170/175 ER/LR
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Confusion; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Aircraft; Human Factors; Chart Or Publication
From the SPIDR3 arrival; which ends at DEEER; we were cleared for the RNAV RNP Y RWY 16; DEEER transition. The last hard altitude on the STAR is SPIDR at 8;000 [feet]. The first altitude restriction on the approach is DEEER; 9 miles after SPIDR; at 4;000 [feet]. The FMS showed a hard altitude of 4;000 [feet] at DEEER. The vertical profile showed a hard altitude at DEEER depicted with the magenta lines above and below the number 4;000; and the aircraft was in VNAV mode; on PTH. Without any 'unable next altitude' message; the plane crossed DEER at 5;700 [feet] (while the vertical profile depicted us precisely on PTH and at 4;000 [feet]) and continued towards the next fix SOOBY which was correctly depicted as at or above 4;000 [feet]. Upon realizing the error; we overrode the automation to expedite the descent to 4;000 [feet]; then re-engaged VNAV. The Controller never mentioned our altitude; only conversing nearly continuously with a VFR aircraft just west of our course; trying to keep them and us constantly aware of each other's position. As far as we can tell; this was an automation error. We were able to duplicate the altitude assignments after blocking in; and reprogramming the FMS for the arrival and approach. It once again depicted SPIDR at 8;000 [feet]; DEEER at 4;000 [feet]; and SOOBY at or above 4;000 [feet]. All correct. Contributing to the automation error may have been the large descent required from SPIDR to DEEER; dropping 4;000 feet in just nine miles. Our understanding is that if the FMS thought this was not possible; we should have gotten an 'unable next altitude' message; OR the Vertical profile should have depicted us high at DEEER. Neither happened. Please correct us if it is apparent that there is something about RNAV approaches or FMS usage that we do not understand. Otherwise; please consult with the designers of this arrival/approach to change the altitude restriction at DEEER to 'at or above.'
EMB-175 Captain reported a lack of agreement between the SPDR 3 RNAV arrival termination fix and the mandatory altitude at the IAF of the RNAV (RNP) Y RWY 16 approach into RIC airport.