EMB ERJ 170/175 ER/LR
Human-Machine Interface; Training / Qualification
Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Aircraft; Human Factors
Captain put in the crossing restriction and we were helping ATC with 'how do u hear this frequency?' Then Captain inserted the approach in the FMS. The FMS dropped the restriction out of VNAV and we did not notice. ATC asked us if we were aware of restriction at GEMINI at 12;000 feet. I said we would not make it and I asked for a vector off airway. We got to 12;000 feet and resumed arrival into DTW. I'm not sure why the FMS dropped the restriction AFTER Captain inserted the approach? He did it again to see if it would drop it again (just to test his theory) and it did it a second time too.
EMB170 First Officer reports an arrival crossing restriction being deleted when the approach is entered in the FMC.