Date: 201706
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Anomaly: Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Airspace Structure
Primary problem: Human Factors

Narrative: An altitude infraction occurred on descent into ZZZ. I was exercising Pilot Flying duties during the descent on the arrival. Initial ATC instruction to follow the published arrival procedure was amended to proceed direct to ZZZZZ intersection; cross ZZZZZ intersection at 12;000 feet at 300 knots. For this flight; the Captain was exercising Pilot Monitoring duties.During the descent; we were preparing for transmitting in range information to company operations in order to retrieve gate assignments and confirm arrival ATIS information. At this time; the ACARS messaging system was inoperative; which increased workload to obtain the information. The Captain was using both left and right side Flight Management Systems to complete in range tasks during this abnormal operation. My duties as Pilot Flying included briefing the approach plan. As part of the Approach Briefing; company procedure requires review of the planned taxi route after landing (to include hot spots). During landing roll; company procedures also necessitate transfer of aircraft control to Captain immediately below designated speeds and Captain's discretion; requiring an immediate change in responsibilities to First Officer for confirming gate availability and coordinating with ground control for safe and efficient movement from the runway environment to surface operations.Information obtained during the descent for gate assignment required the aircraft to position at gate X after landing; for which I personally had limited experience; as the gate is separated from the main hub operations which more frequently occur at other gates. Upon receipt of the gate assignment information and during the descent prior to ZZZZZ intersection; I sought to confirm the necessary taxi route information; as well as gate-specific frequency information and arrival instructions in order to ensure safe and proper surface movement immediately following landing. During this review; I overestimated the time and distance that would be required in order to comply with the ATC instruction; and further did not efficiently use the resources on board in order to make the necessary revised vertical navigation adjustments in the required timeframe. I was reluctant to ask for control of the second FMS unit for the calculation; as the Captain made it very clear early in the trip sequence that I was not to question his methods during the operation.At this time during descent; ATC notified us that the projected flight path did not appear to allow for compliance with the altitude instruction; which we acknowledged. The aircraft was approximately 2-4 miles from ZZZZZ intersection at approximately 14;700 MSL versus the 12;000 MSL assignment at the required 300 knots; which would have required an excessive descent rate to comply with the crossing restriction. ATC further advised that no conflict occurred as a result of the infraction and provided subsequent vectoring in order to intercept final approach course for runway XXL.As part of the preparation for the approach; I was reviewing the post-landing requirements and focused on thorough completion of the approach brief post-landing plan; instead of properly dividing attention and prioritizing descent adjustments and flight path monitoring during the descent and arrival procedure or assertively asking for the necessary help or use of cockpit resources to efficiently complete these tasks. My lack of experience with this particular abnormal equipment operation; familiarity with the airport operations; and hesitance to request for assistance or control of the FMS from the Captain contributed to increased workload during this portion of the flight which led to misjudgment and lapse of adequate vertical navigational scan.




Synopsis: EMB145 First Officer reported being unable to comply with a crossing restriction because the Captain was using both Flight Management Systems.