Mu-2 pilot reported upon landing roll out on snow covered runway began losing directional control up...

Attributes
ACN	1418927
Time
Date	201701
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	MU-2 Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Landing
Route In Use	Visual Approach
Flight Plan	IFR
Component
Aircraft Component	Turbine Engine Thrust Reverser
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Private Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 3.8 Flight Crew Total 4246.7 Flight Crew Type 2587.7
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Ground Event / Encounter Loss Of Aircraft Control Ground Excursion Runway

Narrative:

Approach issued clearance for GPS approach straight in. Descending on GPS approach entered VMC at 3000 MSL approximately 5 miles from runway. Descending to land on runway and saw that the runway was snow covered (not plowed). Made low approach and go around; circle to land. Turned on airport runway lights for better visual reference. Made normal landing in approximately 2 1/2 to 3 inches of light snow. Rolled 150-200 yards straight ahead. Speed below 87 kts. Put power levers into beta. Upon going into beta aircraft yawed to left 30-40 degrees. Right rudder applied but no response. Decision made not to attempt go around. Aircraft continued counterclockwise rotation and skidded off runway with aircraft nose heading approximately 140 degrees. Aircraft stopped 50-70 feet after leaving runway. Initiated emergency shutdown. Exited aircraft. At this point aircraft is awaiting mechanical inspection for any possible discrepancies. Aircraft had newly overhauled engines. Even though the pilot had made 4 takeoffs and landings in the 3 days prior to the incident ; I would seriously consider not landing on a snow covered runway unless in an emergency situation. Numerous landings on snow covered runways prior to this incident were considered normal and safe. This is not the case anymore; because of too many variables that can create an unsafe situation.

Original NASA ASRS Text

Title: MU-2 pilot reported upon landing roll out on snow covered runway began losing directional control upon entering reverse thrust and despite counteracting rudder input went off the end of the runway.

Narrative: Approach issued clearance for GPS Approach straight in. Descending on GPS approach entered VMC at 3000 MSL approximately 5 miles from runway. Descending to land on runway and saw that the runway was snow covered (not plowed). Made low approach and go around; circle to land. Turned on airport runway lights for better visual reference. Made normal landing in approximately 2 1/2 to 3 inches of light snow. Rolled 150-200 yards straight ahead. Speed below 87 kts. put power levers into Beta. Upon going into Beta aircraft yawed to left 30-40 degrees. Right rudder applied but no response. Decision made not to attempt go around. Aircraft continued counterclockwise rotation and skidded off runway with aircraft nose heading approximately 140 degrees. Aircraft stopped 50-70 feet after leaving runway. Initiated emergency shutdown. Exited aircraft. At this point aircraft is awaiting mechanical inspection for any possible discrepancies. Aircraft had newly overhauled engines. Even though the pilot had made 4 takeoffs and landings in the 3 days prior to the incident ; I would seriously consider not landing on a snow covered runway unless in an emergency situation. Numerous landings on snow covered runways prior to this incident were considered normal and safe. This is not the case anymore; because of too many variables that can create an unsafe situation.

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.

Mu-2 pilot reported upon landing roll out on snow covered runway began losing directional control upon entering reverse thrust and despite counteracting rudder input went off the end of the runway.