A B737-300 on takeoff received 2 uncommanded rudder inputs. One at 80 KTS and the second at rotation...

Attributes
ACN	579284
Time
Date	200304
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	ground : takeoff roll
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 6000 flight time type : 2000
ASRS Report	579284
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 15000
ASRS Report	579285
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : flt data recorder other flight crewa other flight crewb
Resolutory Action	aircraft : equipment problem dissipated flight crew : overcame equipment problem flight crew : returned to intended or assigned course
Consequence	other other
Supplementary
Problem Areas	Chart Or Publication Aircraft Flight Crew Human Performance Maintenance Human Performance
Primary Problem	Aircraft

Narrative:

On takeoff runway 8 at ZZZ (winds 130 degrees/10 KTS) we received a gust like mvr (right to left) at 80 KTS, then again at rotation another more aggressive uncommanded rudder pedal input requiring pilot action to maintain control. The second event, in the opinion of both pilots was mechanical rather than environmental. After passing FL180 the captain (PNF) initiated a voice patch to maintenance controller through dispatch. After a lengthy discussion, describing the event to maintenance controller, in maintenance controller's opinion the event was environmentally triggered and not a mechanical issue. Maintenance controller stated there was no further action required. The captain queried maintenance controller as to whether or not an engineering write-up should be made so as to alert the follow-on crew that something unusual had taken place during takeoff. Maintenance controller said 'no, write-up for gusty winds on takeoff was not required.' further discussion by myself and the captain concerning all possible contributors, ie, wind gust, foreign object damage, tire conditions, as well as main and nose gear assemblies, led us to the decision that even though we were not concerned about the safety of the flight, we wanted to document the event for the next flight crew that was to accept the aircraft. The captain then initiated another phone patch to air carrier X dispatch to inform that we would write up the event upon landing and that the aircraft would require a maintenance inspection prior to the next flight. As a precaution the captain advised the flight attendants of the incident and asked the purser to inform the other flight attendants completing a 'cabin advisory.' we further informed ATC that we would like the emergency vehicles standing by upon landing at ZZZ1 in the event of any unusual occurrence. No emergency was declared. Landing was uneventful on runway 12R in ZZZ1. Callback conversation with reporter revealed the following information: the reporter stated no final conclusion has been made as to the cause of the rudder inputs. The reporter said the flight data recorder did record the 80 KT incident.

Original NASA ASRS Text

Title: A B737-300 ON TKOF RECEIVED 2 UNCOMMANDED RUDDER INPUTS. ONE AT 80 KTS AND THE SECOND AT ROTATION. FLT DATA RECORDER NOTED 80 KTS INPUT.

Narrative: ON TKOF RWY 8 AT ZZZ (WINDS 130 DEGS/10 KTS) WE RECEIVED A GUST LIKE MVR (R TO L) AT 80 KTS, THEN AGAIN AT ROTATION ANOTHER MORE AGGRESSIVE UNCOMMANDED RUDDER PEDAL INPUT REQUIRING PLT ACTION TO MAINTAIN CTL. THE SECOND EVENT, IN THE OPINION OF BOTH PLTS WAS MECHANICAL RATHER THAN ENVIRONMENTAL. AFTER PASSING FL180 THE CAPT (PNF) INITIATED A VOICE PATCH TO MAINT CTLR THROUGH DISPATCH. AFTER A LENGTHY DISCUSSION, DESCRIBING THE EVENT TO MAINT CTLR, IN MAINT CTLR'S OPINION THE EVENT WAS ENVIRONMENTALLY TRIGGERED AND NOT A MECHANICAL ISSUE. MAINT CTLR STATED THERE WAS NO FURTHER ACTION REQUIRED. THE CAPT QUERIED MAINT CTLR AS TO WHETHER OR NOT AN ENGINEERING WRITE-UP SHOULD BE MADE SO AS TO ALERT THE FOLLOW-ON CREW THAT SOMETHING UNUSUAL HAD TAKEN PLACE DURING TKOF. MAINT CTLR SAID 'NO, WRITE-UP FOR GUSTY WINDS ON TKOF WAS NOT REQUIRED.' FURTHER DISCUSSION BY MYSELF AND THE CAPT CONCERNING ALL POSSIBLE CONTRIBUTORS, IE, WIND GUST, FOREIGN OBJECT DAMAGE, TIRE CONDITIONS, AS WELL AS MAIN AND NOSE GEAR ASSEMBLIES, LED US TO THE DECISION THAT EVEN THOUGH WE WERE NOT CONCERNED ABOUT THE SAFETY OF THE FLT, WE WANTED TO DOCUMENT THE EVENT FOR THE NEXT FLT CREW THAT WAS TO ACCEPT THE ACFT. THE CAPT THEN INITIATED ANOTHER PHONE PATCH TO ACR X DISPATCH TO INFORM THAT WE WOULD WRITE UP THE EVENT UPON LNDG AND THAT THE ACFT WOULD REQUIRE A MAINT INSPECTION PRIOR TO THE NEXT FLT. AS A PRECAUTION THE CAPT ADVISED THE FLT ATTENDANTS OF THE INCIDENT AND ASKED THE PURSER TO INFORM THE OTHER FLT ATTENDANTS COMPLETING A 'CABIN ADVISORY.' WE FURTHER INFORMED ATC THAT WE WOULD LIKE THE EMER VEHICLES STANDING BY UPON LNDG AT ZZZ1 IN THE EVENT OF ANY UNUSUAL OCCURRENCE. NO EMER WAS DECLARED. LNDG WAS UNEVENTFUL ON RWY 12R IN ZZZ1. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED NO FINAL CONCLUSION HAS BEEN MADE AS TO THE CAUSE OF THE RUDDER INPUTS. THE RPTR SAID THE FLT DATA RECORDER DID RECORD THE 80 KT INCIDENT.

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.

A B737-300 on takeoff received 2 uncommanded rudder inputs. One at 80 KTS and the second at rotation. Flight data recorder noted 80 KTS input.