CE550 captain reported overshooting a cleared altitude while descending in icing conditions with a f...

Attributes
ACN	1619731
Time
Date	201902
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	Citation II S2/Bravo (C550)
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Intake Ice System
Person 1
Function	Captain Pilot Flying Single Pilot
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 120 Flight Crew Total 13500 Flight Crew Type 2500
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence

Narrative:

While on descent out of FL250 it was reported there was light rime ice just about 50 miles northwest of ZZZ. I acknowledged. About 2 minutes later we entered the clouds and I turned my anti ice systems on. I then began picking up ice. My left engine ice failed and I immediately asked for lower stating that I was having device systems issues. Center descended me immediately to FL210. Once I started the descent I began reading checklists and working the system. I then noticed the autopilot altitude select didn't arm and I descended below my assigned altitude. Once I realized it I was starting back up but center just cleared me to 13;000 feet. They never said anything to me and there wasn't another aircraft in the area. No deviations or conflicts. The main issue was dealing with the deice problem while getting ice in the descent. I was descending at 2500 ft min to get below the ice which was around 19;500 feet.

Original NASA ASRS Text

Title: CE550 Captain reported overshooting a cleared altitude while descending in icing conditions with a failure of the left engine anti-ice system.

Narrative: While on descent out of FL250 it was reported there was light rime ice just about 50 miles NW of ZZZ. I acknowledged. About 2 minutes later we entered the clouds and I turned my anti ice systems on. I then began picking up ice. My left engine ice failed and I immediately asked for lower stating that I was having device systems issues. Center descended me immediately to FL210. Once I started the descent I began reading checklists and working the system. I then noticed the autopilot altitude select didn't arm and I descended below my assigned altitude. Once I realized it I was starting back up but Center just cleared me to 13;000 feet. They never said anything to me and there wasn't another aircraft in the area. No deviations or conflicts. The main issue was dealing with the deice problem while getting ice in the descent. I was descending at 2500 ft min to get below the ice which was around 19;500 feet.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

CE550 captain reported overshooting a cleared altitude while descending in icing conditions with a failure of the left engine anti-ice system.