Nose wheel steering failure on widebody transport as aircraft was turned on high speed taxiway.

Attributes
ACN	198659
Time
Date	199201
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mbj
State Reference	FO
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tower : cvg
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	ground other : taxi landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 150 flight time total : 18000 flight time type : 2600
ASRS Report	198659
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	other Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

After landing and attempting to use a right high speed turnoff, the nose wheel steering seemed stiff in the right turn. When the steering was brought back to neutral, the nose gear went hard left (approximately 90-110 degrees) and locked in that position. The aircraft was towed off the runway and to the gate. Maintenance found 1 of 2 spliced wires to the nose wheel steering electro hydraulic selector valve broken. No other damage was found, no scuff marks on the tires and no skid marks on the runway or high speed taxiway. In my opinion, in the event an electrical failure to this valve should occur, it should default to a neutral position. Failure at a higher speed then ours could be catastrophic.

Original NASA ASRS Text

Title: NOSE WHEEL STEERING FAILURE ON WDB AS ACFT WAS TURNED ON HIGH SPD TAXIWAY.

Narrative: AFTER LNDG AND ATTEMPTING TO USE A R HIGH SPD TURNOFF, THE NOSE WHEEL STEERING SEEMED STIFF IN THE R TURN. WHEN THE STEERING WAS BROUGHT BACK TO NEUTRAL, THE NOSE GEAR WENT HARD L (APPROX 90-110 DEGS) AND LOCKED IN THAT POS. THE ACFT WAS TOWED OFF THE RWY AND TO THE GATE. MAINT FOUND 1 OF 2 SPLICED WIRES TO THE NOSE WHEEL STEERING ELECTRO HYD SELECTOR VALVE BROKEN. NO OTHER DAMAGE WAS FOUND, NO SCUFF MARKS ON THE TIRES AND NO SKID MARKS ON THE RWY OR HIGH SPD TAXIWAY. IN MY OPINION, IN THE EVENT AN ELECTRICAL FAILURE TO THIS VALVE SHOULD OCCUR, IT SHOULD DEFAULT TO A NEUTRAL POS. FAILURE AT A HIGHER SPD THEN OURS COULD BE CATASTROPHIC.

Data retrieved from NASA's ASRS site as of July 2007 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.