Date: 202102
Local time of day: 0601-1200
Location: ZZZ.TRACON, US
Flight conditions: IMC
Aircraft: B737-400
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Climb; Initial Climb
Airspace: Class A ZOB
ATC / advisory: TRACON ZZZ
Aircraft component: Flight Dynamics Navigation and Safety
Component problem: Failed; Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Critical; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance
Result: General None Reported / Taken
Contributing factors: Software and Automation; Human Factors; Aircraft
Primary problem: Human Factors

Narrative: Upon departing ZZZ early in the morning; both the PF and PNF flight directors failed shortly after takeoff; prompting the PNF to quickly reference the QRH after several attempts to rectify the situation. After the completion of checklists; during the climb out and initial cruise; it was discovered that the FMC had also frozen up; not allowing any keypad inputs for route modifications. Shortly after leveling off at our cruise altitude; the PNF continued to troubleshoot the problem and was eventually successful at restoring both flight directors and FMC's back to normal. Meanwhile; during descent into ZZZ1; ARTCC advised us of a crossing restriction that was not complied with. We immediately stopped our descent and apologized. ARTCC then handed us off to ZZZ1 approach; after which; the flight continued on without further incident. It is suspected that the electronic malfunction of both the flight directors and FMC's; may have deleted or affected the altitude crossing restrictions; or; ARTCC may have linguistically confused the pronunciation of ZZZZZ with the ZZZZZ1 arrival into ZZZ1; as our flight plan indicated. Per SOP (Standard Operating Procedure); maintenance was notified of the situation but unable to determine cause or reproduce the fault.As for the electronic equipment malfunction; both the PF and the PNF became aware of the flight director failures shortly after takeoff when trying to engage VNAV. The FMC was determined to have failed during climb out. As for the altitude deviation; this issue was brought to our attention by ARTCC after crossing the fix below the published crossing altitude.The cause of the electrical/ electronic failure involving the flight directors and FMC's was undetermined by maintenance and could not be reproduced. The failure to comply with altitude crossing restrictions at a fix; may have been due to ARTCC assuming we were given the ZZZZZ1 arrival instead of the ZZZZZ arrival; which was listed on our flight release and selected in our FMC. My reaction was calm but assertive in continuing to fly the aircraft as the PNF; troubleshot the problem.As for the electronic equipment malfunctions; these failures are unpredictable. As for the crossing restriction compliance; our flight planning documents indicate that the correct arrival procedure was selected in the FMC but ARTCC thought different. In the future; I will be a little bit more willing to question; and/ or; verify an ATC challenge rather than assume their always right!




Synopsis: Flight Crew flying 737-400 aircraft were notified by ATC of crossing restriction not complied with.