Cessna Citation Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 40; Flight Crew Total 8700; Flight Crew Type 500
Communication Breakdown; Confusion; Distraction; Troubleshooting
ATC Issue All Types; Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Equipment / Tooling; Aircraft
Enroute to ZZZ on R576 on a daytime flight in VMC (Visual Meteorological Conditions). Flight planned altitude was FL430 to DADIE waypoint then climb to FL450 by DIALO waypoint. Approaching DADIE the Pilot Flying confirmed the plan to initiate a constant mach climb to FL450 by DIALO and asked for FL450 to be set in the altitude preselect which was accomplished. The Pilot Monitoring initiated the required voice position report via HF to [Oakland Oceanic]. Communication was difficult on the primary HF (High Frequency) frequency and it took several exchanges to confirm the position report. The PF (Pilot Flying) was monitoring VHF (Very High Frequency) frequencies 123.45 and 121.50 during the position report and initiated a climb to FL450 assuming the Pilot Monitoring had communicated the climb to FL450. Due to the distraction of the HF position report the Pilot Monitoring neglected to request a climb to FL450 and focused on completing the navigation log following the HF communication. Upon reporting the next position report at DIALO [Oakland Oceaninc] queried the altitude which was confirmed as FL450 and the crew realized they had not received clearance confirmation to make the flight planned climb from FL430 to FL450. ATC re-cleared the flight to maintain FL450 and reiterated a clearance was required to initiate the climb. The confusion caused by the difficulty with the HF communication associated with the position report at DADIE contributed to the error.
Citation flight crew experienced an HF radio issue that resulted in a clearance deviation.