Narrative:

ZZZ sky condition broken; ceilings approximately 2000 ft; tops approximately 4500 ft; surface winds at 170 degrees at 5-8 KTS. Approximately 40 mi south of ZZZ; I called ATC and requested IFR clearance for approach into ZZZ. Request approved; assigned altitude 5000 ft. Received 'direct-to' clearance to IAF altitude 2400 ft; 8-10 mi south of IAF. Cleared for ILS approach runway 7 approximately 5-8 mi south of IAF; altitude 2400 ft. Established on approach at IAF at approximately XA40. Approach uneventful to touchdown on runway 7. Touchdown occurred within landing zone on centerline of runway 7; time approximately XA45; at this point landing uneventful. As nosewheel touched down; aircraft veered sharply to right. Attempted to correct direction by applying left rudder -- no differential braking was applied. Aircraft left runway. No effect from application of left rudder was noted. After leaving runway full up elevator was applied; power was at idle; left rudder continuously applied with no effect. As aircraft slowed to a stop; nosewheel sank in the mud with propeller striking mud and stopping engine. Callback conversation with reporter revealed the following information: the reporter stated that the aircraft was examined by two separate mechanics who gave differing causes for the failure. The mechanic at the station where the aircraft had the excursion said the nosewheel system had a malfunction and indeed could not be controlled by the pilot. The FBO mechanic who normally maintained the aircraft said that the pilot did not use differential braking and therefore could not control the aircraft. The reporter stated that indeed he did not use differential braking but did not because he feared ground looping the aircraft. Because of the sudden stoppage when the propeller hit the mud the engine had been disassembled for inspection. There was no other damage to the aircraft. The reporter still questions himself and whether the event could have been prevented or was result of his not using hard differential braking to correct the drift.

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Original NASA ASRS Text

Title: A C172 DEPARTED THE RWY FOLLOWING A NORMAL APCH WHEN THE NOSEWHEEL STUCK CAUSING THE ACFT TO DEPART THE RWY. RUDDER INPUT DID NOT CORRECT ACFT.

Narrative: ZZZ SKY CONDITION BROKEN; CEILINGS APPROX 2000 FT; TOPS APPROX 4500 FT; SURFACE WINDS AT 170 DEGS AT 5-8 KTS. APPROX 40 MI S OF ZZZ; I CALLED ATC AND REQUESTED IFR CLRNC FOR APCH INTO ZZZ. REQUEST APPROVED; ASSIGNED ALT 5000 FT. RECEIVED 'DIRECT-TO' CLRNC TO IAF ALT 2400 FT; 8-10 MI S OF IAF. CLRED FOR ILS APCH RWY 7 APPROX 5-8 MI S OF IAF; ALT 2400 FT. ESTABLISHED ON APCH AT IAF AT APPROX XA40. APCH UNEVENTFUL TO TOUCHDOWN ON RWY 7. TOUCHDOWN OCCURRED WITHIN LNDG ZONE ON CTRLINE OF RWY 7; TIME APPROX XA45; AT THIS POINT LNDG UNEVENTFUL. AS NOSEWHEEL TOUCHED DOWN; ACFT VEERED SHARPLY TO R. ATTEMPTED TO CORRECT DIRECTION BY APPLYING L RUDDER -- NO DIFFERENTIAL BRAKING WAS APPLIED. ACFT LEFT RWY. NO EFFECT FROM APPLICATION OF L RUDDER WAS NOTED. AFTER LEAVING RWY FULL UP ELEVATOR WAS APPLIED; PWR WAS AT IDLE; L RUDDER CONTINUOUSLY APPLIED WITH NO EFFECT. AS ACFT SLOWED TO A STOP; NOSEWHEEL SANK IN THE MUD WITH PROP STRIKING MUD AND STOPPING ENG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT THE ACFT WAS EXAMINED BY TWO SEPARATE MECHANICS WHO GAVE DIFFERING CAUSES FOR THE FAILURE. THE MECHANIC AT THE STATION WHERE THE ACFT HAD THE EXCURSION SAID THE NOSEWHEEL SYSTEM HAD A MALFUNCTION AND INDEED COULD NOT BE CONTROLLED BY THE PILOT. THE FBO MECHANIC WHO NORMALLY MAINTAINED THE ACFT SAID THAT THE PILOT DID NOT USE DIFFERENTIAL BRAKING AND THEREFORE COULD NOT CONTROL THE ACFT. THE REPORTER STATED THAT INDEED HE DID NOT USE DIFFERENTIAL BRAKING BUT DID NOT BECAUSE HE FEARED GND LOOPING THE ACFT. BECAUSE OF THE SUDDEN STOPPAGE WHEN THE PROP HIT THE MUD THE ENGINE HAD BEEN DISASSEMBLED FOR INSPECTION. THERE WAS NO OTHER DAMAGE TO THE ACFT. THE REPORTER STILL QUESTIONS HIMSELF AND WHETHER THE EVENT COULD HAVE BEEN PREVENTED OR WAS RESULT OF HIS NOT USING HARD DIFFERENTIAL BRAKING TO CORRECT THE DRIFT.

Data retrieved from NASA's ASRS site as of January 2009 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.