Narrative:

During the descent from our cruising altitude, prior to 10000 ft, the PF said, 'did you feel that?' having felt nothing, I said 'what?' he asked if I felt a rudder kick. I said no, set aside charts, and focused entirely on the aircraft's movement. Moments later, I thought I felt a very faint, short cycled yaw of the aircraft. Had he not mentioned the rudder or not been in smooth air, I would not have been able to feel such a slight/faint movement. In fact, I cannot be certain that what we felt was a flight control induced movement versus air mass movement. Whatever happened was so mild in intensity and brief in duration that it did not bear mentioning. (There were no secondary indications of aircraft problems of any kind.) I was unaware that the aircraft had been grounded about 2 weeks prior for rudder kick. The aircraft, as of jun/mon/96, has been grounded 2 times since may/fri/96. Both the captain and I agree that what he, then we, felt could easily have been mild air mass movement. Given the significance of rudder kick in the B737, I am submitting this statement. Callback conversation with reporter revealed the following information: the reporter flies the B737-200 for an air carrier that has only 2 aircraft. The maintenance is contracted to only 1 air carrier, the air carrier that sold the aircraft to the reporter's air carrier. The captain had been aware of other rudder incidents but the reporting first officer had not. The reporter is upset with his air carrier for not having warned its pilots about the rudder incidents previous to this one. After another incident with this same aircraft, the FAA, NTSB, and boeing all were brought into the picture and the aircraft was reworked extensively. The reporter, now a captain, believes that there have been no further rudder incidents with this aircraft since the rework. He is now aware of the FAA safety hotline.

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Original NASA ASRS Text

Title: ANOTHER ACR B737-200 CREW RPTS AN UNCOMMANDED RUDDER KICK OR YAW. THE ACFT HAS BEEN EXTENSIVELY REWORKED. THE FAA, NTSB AND BOEING WERE ALL INVOLVED WITH THE REWORK.

Narrative: DURING THE DSCNT FROM OUR CRUISING ALT, PRIOR TO 10000 FT, THE PF SAID, 'DID YOU FEEL THAT?' HAVING FELT NOTHING, I SAID 'WHAT?' HE ASKED IF I FELT A RUDDER KICK. I SAID NO, SET ASIDE CHARTS, AND FOCUSED ENTIRELY ON THE ACFT'S MOVEMENT. MOMENTS LATER, I THOUGHT I FELT A VERY FAINT, SHORT CYCLED YAW OF THE ACFT. HAD HE NOT MENTIONED THE RUDDER OR NOT BEEN IN SMOOTH AIR, I WOULD NOT HAVE BEEN ABLE TO FEEL SUCH A SLIGHT/FAINT MOVEMENT. IN FACT, I CANNOT BE CERTAIN THAT WHAT WE FELT WAS A FLT CTL INDUCED MOVEMENT VERSUS AIR MASS MOVEMENT. WHATEVER HAPPENED WAS SO MILD IN INTENSITY AND BRIEF IN DURATION THAT IT DID NOT BEAR MENTIONING. (THERE WERE NO SECONDARY INDICATIONS OF ACFT PROBS OF ANY KIND.) I WAS UNAWARE THAT THE ACFT HAD BEEN GNDED ABOUT 2 WKS PRIOR FOR RUDDER KICK. THE ACFT, AS OF JUN/MON/96, HAS BEEN GNDED 2 TIMES SINCE MAY/FRI/96. BOTH THE CAPT AND I AGREE THAT WHAT HE, THEN WE, FELT COULD EASILY HAVE BEEN MILD AIR MASS MOVEMENT. GIVEN THE SIGNIFICANCE OF RUDDER KICK IN THE B737, I AM SUBMITTING THIS STATEMENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLIES THE B737-200 FOR AN ACR THAT HAS ONLY 2 ACFT. THE MAINT IS CONTRACTED TO ONLY 1 ACR, THE ACR THAT SOLD THE ACFT TO THE RPTR'S ACR. THE CAPT HAD BEEN AWARE OF OTHER RUDDER INCIDENTS BUT THE RPTING FO HAD NOT. THE RPTR IS UPSET WITH HIS ACR FOR NOT HAVING WARNED ITS PLTS ABOUT THE RUDDER INCIDENTS PREVIOUS TO THIS ONE. AFTER ANOTHER INCIDENT WITH THIS SAME ACFT, THE FAA, NTSB, AND BOEING ALL WERE BROUGHT INTO THE PICTURE AND THE ACFT WAS REWORKED EXTENSIVELY. THE RPTR, NOW A CAPT, BELIEVES THAT THERE HAVE BEEN NO FURTHER RUDDER INCIDENTS WITH THIS ACFT SINCE THE REWORK. HE IS NOW AWARE OF THE FAA SAFETY HOTLINE.

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.