A C421 pilot reported losing nose wheel steering on taxi out; resulting in an excursion into the mud...

Attributes
ACN	1001652
Time
Date	201203
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	Golden Eagle 421
Operating Under FAR Part	Part 91
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Nosewheel Steering
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 6900 Flight Crew Type 100
Events
Anomaly	Aircraft Equipment Problem Critical Ground Event / Encounter Loss Of Aircraft Control Ground Excursion Taxiway

Narrative:

During taxi the aircraft experienced a loss of nose wheel steering and the aircraft began to veer to the right. Left rudder input and left differential braking were unable to overcome the right hand turn and prevent the aircraft from exiting the taxiway. The use of differential power on the right engine to attempt to control the right turn was also unsuccessful in turning the aircraft. The right main gear departed the taxiway and entered into soft mud which pulled the aircraft to the right and caused the aircraft to come to a stop with the nose wheel approximately 10 ft off the taxiway. There were no injuries to report and all passengers exited the aircraft once the engines were secured.

Original NASA ASRS Text

Title: A C421 pilot reported losing nose wheel steering on taxi out; resulting in an excursion into the mud.

Narrative: During taxi the aircraft experienced a loss of nose wheel steering and the aircraft began to veer to the right. Left rudder input and left differential braking were unable to overcome the right hand turn and prevent the aircraft from exiting the taxiway. The use of differential power on the right engine to attempt to control the right turn was also unsuccessful in turning the aircraft. The right main gear departed the taxiway and entered into soft mud which pulled the aircraft to the right and caused the aircraft to come to a stop with the nose wheel approximately 10 FT off the taxiway. There were no injuries to report and all passengers exited the aircraft once the engines were secured.

Data retrieved from NASA's ASRS site as of July 2013 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.