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An air carrier MD80 flight crew experiences a yawing moment in the aircraft during their initial climb out. They shut off the yaw damper, retrim the aircraft and return to stl.
| Attributes | |
| ACN | 365240 |
| Time | |
| Date | 199704 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : stl |
| State Reference | MO |
| Altitude | msl bound lower : 605 msl bound upper : 6000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : stl tower : stl tower : ewr |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | climbout : initial landing other other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 2500 flight time type : 250 |
| ASRS Report | 365240 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | other flight crewa |
| Resolutory Action | other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
After takeoff on climb out of stl, aircraft started to roll left and right. Turning off yaw damper stopped rolling. Returned to stl and landed. Callback conversation with reporter revealed the following information: the first officer said that the initial yaw was 5 or 6 degrees either side of the aircraft's centerline and after shutting the yaw damper off the aircraft stayed in a slip for a while. He said that the slip was 5 to 10 degrees to the left and the captain was able to trim it out so that the final approach was normal. This analyst questioned the reporter as to whether the rudder's PCU may have been displaced and he said that the slip felt like that, but he never got a confirmation from the mechanics who met the aircraft. The mechanics, according to the reporter, said that the wiring to the yaw damper appeared to be chafed and had evidence of shorting. He has asked since this experience, but nobody that he has talked to at maintenance seems to know what repairs were done.
Original NASA ASRS Text
Title: AN ACR MD80 FLC EXPERIENCES A YAWING MOMENT IN THE ACFT DURING THEIR INITIAL CLB OUT. THEY SHUT OFF THE YAW DAMPER, RETRIM THE ACFT AND RETURN TO STL.
Narrative: AFTER TKOF ON CLBOUT OF STL, ACFT STARTED TO ROLL L AND R. TURNING OFF YAW DAMPER STOPPED ROLLING. RETURNED TO STL AND LANDED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE FO SAID THAT THE INITIAL YAW WAS 5 OR 6 DEGS EITHER SIDE OF THE ACFT'S CTRLINE AND AFTER SHUTTING THE YAW DAMPER OFF THE ACFT STAYED IN A SLIP FOR A WHILE. HE SAID THAT THE SLIP WAS 5 TO 10 DEGS TO THE L AND THE CAPT WAS ABLE TO TRIM IT OUT SO THAT THE FINAL APCH WAS NORMAL. THIS ANALYST QUESTIONED THE RPTR AS TO WHETHER THE RUDDER'S PCU MAY HAVE BEEN DISPLACED AND HE SAID THAT THE SLIP FELT LIKE THAT, BUT HE NEVER GOT A CONFIRMATION FROM THE MECHS WHO MET THE ACFT. THE MECHS, ACCORDING TO THE RPTR, SAID THAT THE WIRING TO THE YAW DAMPER APPEARED TO BE CHAFED AND HAD EVIDENCE OF SHORTING. HE HAS ASKED SINCE THIS EXPERIENCE, BUT NOBODY THAT HE HAS TALKED TO AT MAINT SEEMS TO KNOW WHAT REPAIRS WERE DONE.
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.