D328 captain reported diverting to an alternate airport after experiencing failure of vertical and h...

Narrative:

Upon reaching FL260; aircraft encountered moderate to heavy-moderate clear/rime icing and experienced a failure in the vertical and horizontal stabilizer de-icing boots. Crew attempted to mitigate icing conditions by climbing to FL280; then to FL300. Any deviations from cleared altitude [were] to avoid icing conditions for safety of flight considerations. Unable to avoid icing by climbing; the crew requested center to provide information on areas clear of clouds for descent below cloud deck. Center approved course deviation and descent towards [a nearby airport]. During descent; the aircraft had an environmental control system (ecs) pack fail above FL260; which then resulted in an uncommanded cabin depressurization. The crew went on oxygen and stated to ATC of an in-flight emergency. After requesting the location of the nearest airfield with at least 3000 feet of runway length; center approved the crew to divert to [the nearest appropriate airport]. The crew landed safely with no physiological incidents and with no indications of aircraft damage.the crew operated the aircraft within all approved standard operating procedures and operating limits; so it is unknown caused this issues. To prevent future occurrence; crew should immediately request courses/altitudes clear of icing conditions.

Original NASA ASRS Text

Title: D328 Captain reported diverting to an alternate airport after experiencing failure of vertical and horizontal stabilizer deicing systems in icing conditions.

Narrative: Upon reaching FL260; aircraft encountered moderate to heavy-moderate clear/rime icing and experienced a failure in the vertical and horizontal stabilizer de-icing boots. Crew attempted to mitigate icing conditions by climbing to FL280; then to FL300. Any deviations from cleared altitude [were] to avoid icing conditions for safety of flight considerations. Unable to avoid icing by climbing; the crew requested Center to provide information on areas clear of clouds for descent below cloud deck. Center approved course deviation and descent towards [a nearby airport]. During descent; the aircraft had an Environmental Control System (ECS) pack fail above FL260; which then resulted in an uncommanded cabin depressurization. The crew went on oxygen and stated to ATC of an in-flight emergency. After requesting the location of the nearest airfield with at least 3000 feet of runway length; Center approved the crew to divert to [the nearest appropriate airport]. The crew landed safely with no physiological incidents and with no indications of aircraft damage.The crew operated the aircraft within all approved standard operating procedures and operating limits; so it is unknown caused this issues. To prevent future occurrence; crew should immediately request courses/altitudes clear of icing conditions.

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.

Attributes
ACN	1520020
Time
Date	201802
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Make Model Name	Do 328 TP (Turboprop)
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	Captain Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 60 Flight Crew Total 2500 Flight Crew Type 250
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Weather / Turbulence

D328 captain reported diverting to an alternate airport after experiencing failure of vertical and horizontal stabilizer deicing systems in icing conditions.