|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : cvg|
|Altitude||agl bound lower : 0|
agl bound upper : 3000
|Controlling Facilities||tower : cvg|
|Operator||common carrier : air carrier|
|Make Model Name||Large Transport, Low Wing, 3 Turbojet Eng|
|Flight Phase||climbout : intermediate altitude|
climbout : takeoff
climbout : initial
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : commercial|
pilot : flight engineer
pilot : private
pilot : atp
pilot : cfi
|Experience||flight time last 90 days : 150|
flight time total : 13000
flight time type : 500
|Anomaly||aircraft equipment problem : critical|
|Independent Detector||aircraft equipment other aircraft equipment : unspecified|
other flight crewa
|Resolutory Action||flight crew : overcame equipment problem|
|Air Traffic Incident||other|
After takeoff, upon raising flaps, aircraft required excessive left aileron to maintain level flight. Surface position indicator (yaw dampers) indicated lower rudder deflection to the right. I called for flaps to be lowered and the rudder deflection decreased. I returned to the airport where it was determined the lower rudder yaw damper had deflected incorrectly. The surface position indicator showed (in flight) what appeared to be upper rudder to the left and lower rudder to the right, so I was unsure which rudder was acting improperly. I knew that when the aircraft was in a dirty confign that I could control the aircraft in a fairly normal manner, so I did not think that it was appropriate to troubleshoot the problem. I slowed the aircraft down, lowered the flaps and returned to the takeoff airport uneventfully. Callback conversation with reporter revealed the following: maintenance said the problem was a transient signal input and changed the damper sensor. The PIC then elected to deactivate the lower yaw damper and redispatched applying damper out restrictions. After 3 flight segments other yaw damper components were changed correcting the problem. Reporter said he noticed a slight deflection of the rudder position indicator before the first takeoff but thought it was due to 2 sharp left turns made while positioning the aircraft for takeoff. Also they were taxiing fast and made a rolling takeoff, so control check was not as thorough as usual.
Original NASA ASRS Text
Title: ACR LGT REQUIRED EXCESSIVE AILERON TO CTL ROLL TENDENCY AS SPEED INCREASED DURING CLEAN UP AFTER TKOF. FLT CREW REDUCED SPEED LOWERED FLAPS AND RETUREND TO DEP ARPT.
Narrative: AFTER TKOF, UPON RAISING FLAPS, ACFT REQUIRED EXCESSIVE LEFT AILERON TO MAINTAIN LEVEL FLT. SURFACE POS INDICATOR (YAW DAMPERS) INDICATED LOWER RUDDER DEFLECTION TO THE RIGHT. I CALLED FOR FLAPS TO BE LOWERED AND THE RUDDER DEFLECTION DECREASED. I RETURNED TO THE ARPT WHERE IT WAS DETERMINED THE LOWER RUDDER YAW DAMPER HAD DEFLECTED INCORRECTLY. THE SURFACE POS INDICATOR SHOWED (IN FLT) WHAT APPEARED TO BE UPPER RUDDER TO THE LEFT AND LOWER RUDDER TO THE RIGHT, SO I WAS UNSURE WHICH RUDDER WAS ACTING IMPROPERLY. I KNEW THAT WHEN THE ACFT WAS IN A DIRTY CONFIGN THAT I COULD CTL THE ACFT IN A FAIRLY NORMAL MANNER, SO I DID NOT THINK THAT IT WAS APPROPRIATE TO TROUBLESHOOT THE PROB. I SLOWED THE ACFT DOWN, LOWERED THE FLAPS AND RETURNED TO THE TKOF ARPT UNEVENTFULLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: MAINT SAID THE PROB WAS A TRANSIENT SIGNAL INPUT AND CHANGED THE DAMPER SENSOR. THE PIC THEN ELECTED TO DEACTIVATE THE LOWER YAW DAMPER AND REDISPATCHED APPLYING DAMPER OUT RESTRICTIONS. AFTER 3 FLT SEGMENTS OTHER YAW DAMPER COMPONENTS WERE CHANGED CORRECTING THE PROB. RPTR SAID HE NOTICED A SLIGHT DEFLECTION OF THE RUDDER POS INDICATOR BEFORE THE FIRST TKOF BUT THOUGHT IT WAS DUE TO 2 SHARP LEFT TURNS MADE WHILE POSITIONING THE ACFT FOR TKOF. ALSO THEY WERE TAXIING FAST AND MADE A ROLLING TKOF, SO CTL CHK WAS NOT AS THOROUGH AS USUAL.
Data retrieved from NASA's ASRS site as of August 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.