Citationjet (C525/C526) - CJ I / II / III / IV
Flight Crew Instrument; Flight Crew Multiengine
Human-Machine Interface; Distraction; Confusion; Situational Awareness
Aircraft Equipment Problem Critical; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Aircraft Equipment Problem Dissipated; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
ATC Equipment / Nav Facility / Buildings; Aircraft
Routine return flight. Everything was normal up until our climb from 28;500 thru 29;000 feet when suddenly the autopilot annunciation sounded and then followed by a complete GPS failure. We let ATC know the issues we were dealing with and they gave us a heading and an altitude. I was currently the Pilot Flying and given 27;000 feet. On our descent back down to 27;000 feet; we were working hard to get the avionics issue figured out and I believe there was a miscommunication between the Pilot Flying and Pilot Monitoring regarding our selected altitude. Workload was at its peak and we leveled off at 28;000 feet momentarily. While hand flying; we determined flight guidance system 1 and 2 had failed. ATC gave us off route vectors and were very understanding of our situation and very patient with us. It was about 30 seconds between our brief level off at 28;000 feet when ATC politely asked us to descend to 27;000 feet when workload permitted. We made our descent to 27;000 feet and after about a total of 5 minutes; we regained GPS signal and Flight Guidance system began working as normal. Crew coordination and verifying altitudes during an abnormal operations like we experienced should have remained an essential item to cross check and confirm.
A pilot reported they temporarily lost the GPS signal.