C210 pilot reports encountering unforecast weather enroute to ege and elects to divert to mjt. Icing...

Attributes
ACN	916993
Time
Date	201010
Local Time Of Day	0601-1200
Place
Locale Reference	MTJ.Airport
State Reference	US
Aircraft 1
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C 210D
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Aerofoil Ice System
Person 1
Function	Single Pilot
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 475 Flight Crew Type 150
Events
Anomaly	Aircraft Equipment Problem Critical Inflight Event / Encounter Weather / Turbulence

Narrative:

Enroute to ege; the weather at ege and alternate gjt both dropped below their forecast and below what I felt was necessary for safe operations. Weather at mtj was good VFR. I decided to divert to mtj. During final cruise and descent I encountered icing conditions while deviating around showers. De-ice boots malfunctioned upon activation resulting in ice accumulation. In order to maintain a safe flying speed I was unable to maintain the assigned altitude and descended to an altitude at which I could maintain a safe speed and altitude. No terrain warning was activated. The inaccurate terminal forecast and the de-ice boots malfunction contributed to this situation. In the future I will check the de-ice boots operation prior to encountering icing conditions. The de-ice system has been referred for corrective maintenance.

Original NASA ASRS Text

Title: C210 pilot reports encountering unforecast weather enroute to EGE and elects to divert to MJT. Icing conditions are encountered and the wing deice system fails upon activation. Reporter elects to descend below assigned altitude to maintain flying speed and get out of icing conditions.

Narrative: Enroute to EGE; the weather at EGE and alternate GJT both dropped below their forecast and below what I felt was necessary for safe operations. Weather at MTJ was good VFR. I decided to divert to MTJ. During final cruise and descent I encountered icing conditions while deviating around showers. De-ice boots malfunctioned upon activation resulting in ice accumulation. In order to maintain a safe flying speed I was unable to maintain the assigned altitude and descended to an altitude at which I could maintain a safe speed and altitude. No terrain warning was activated. The inaccurate terminal forecast and the de-ice boots malfunction contributed to this situation. In the future I will check the de-ice boots operation prior to encountering icing conditions. The de-ice system has been referred for corrective maintenance.

Data retrieved from NASA's ASRS site as of April 2012 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.

C210 pilot reports encountering unforecast weather enroute to ege and elects to divert to mjt. Icing conditions are encountered and the wing deice system fails upon activation. Reporter elects to descend below assigned altitude to maintain flying speed and get out of icing conditions.