Date: 201701
Local time of day: 0001-0600
Location: RNO.Airport, CA
Flight conditions: Marginal
Weather elements / visibility: Cloudy; 6
Light: Night
Aircraft: Citation II S2/Bravo (C550)
Operator: Air Taxi
Operating under: Part 91
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Initial Approach
Airspace: Class E NCT
ATC / advisory: TRACON NCT
Reporter organization: Air Taxi
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Engineer; Flight Crew Flight Instructor; Flight Crew Instrument
Human factors: Distraction; Human-Machine Interface; Fatigue
Second reporter function: Captain; Pilot Not Flying
Anomaly: Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Returned To Clearance; Flight Crew FLC Overrode Automation
Contributing factors: Aircraft; Human Factors; Weather
Primary problem: Human Factors

Narrative: I was the co-pilot and flying pilot with no passengers. This was the third mission in this airplane and unlike the usual aircraft I fly this one has a glass cockpit with the Mode Control Panel in front of the Captain. We had worked together very well as a crew with excellent CRM. We were descending to land at RNO where the weather was about 1200 overcast with tops about 8000 ft and because of the temperature; icing was expected; level unknown. The autopilot was engaged. I had briefed the approach and we completed the appropriate checklists. We were getting step down descents and when we were cleared from 10000 to 9000 ft. I saw the captain select 9000 in the altitude preselect window but failed to notice the arm button was not pushed. I had just called for engine anti-ice to be turned on and we were discussing when to turn on the wing anti-ice. Then I noticed the airplane going through 8700 ft. I immediately disconnected the autopilot and started a climb back to 9000. Just as the airplane started climbing ATC announced 'stop your descent.'  We received further vectors and descents and accomplished the approach; landing in RNO.Contributing factors were I had little time on this glass panel airplane; night flight; IFR weather ahead with possible icing and busy time of flight. We lost situational awareness and my inaction was not confirming autopilot status and reliance on automation.


Second narrative: Prior to descent; all appropriate checklists/briefs were complete in accordance with SOPs. PF was descending to assigned altitude of 10;000 ft. Pilots entered brief conversation about cloud deck; thickness and potential icing. Decision was made to turn anti-ice on (anti-ice switches accessed from left seat) PNF moved to select AI switches 'ON.' Concurrently; ATC directed a descent from 10;000 to 9;000 just prior to PF reaching 10;000 (SOP calls for PNF to select/reset alt preselect controller to new alt (9;000) and select ALT ARM -- this is to be announced and subsequently acknowledge by PF). Upon receipt of ATC instructions; PNF selected 9;000 in Alt pre-select window. Announced 'Pilot; cleared to 9;000.' PNF failed to select ARM as attention went back to verifying proper anti-ice controls were in place. Acknowledgment of 'preselects' did not occur. Passing through 8800; PF recognized AP failed to capture preselected altitude of 9;000. PF interrupted AP and started a smooth climb (night IMC conditions at this time) back to 9;000. In process of maneuvering; the aircraft descended to 8700. During climb back to 9;000 ATC directed 'Stop descent.' During climb back to altitude; ATC directed subsequent vector and descent to intercept the LOC with clearance for approach. Subsequent approach was uneventful.ROOT CAUSE: Failure to follow SOP.CAUSAL FACTORS: Distraction due to environmental factors; Crew fatigue; early morning hours; PF completed early morning sortie the day prior. Although it was the fourth leg of mission the PNF had not flown in 17 days.


Synopsis: C550 pilots reported incorrectly setting their altitude during a descent to RNO resulting in overshooting their assigned altitude.