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A B737-300 on takeoff roll rejected the takeoff at 130 KTS due to a small well defined yaw input and sloppy steering.
| Attributes | |
| ACN | 434236 |
| Time | |
| Date | 199904 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : las.airport |
| State Reference | NV |
| Altitude | agl single value : 0 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : las.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | ground : takeoff roll |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : multi engine pilot : flight engineer pilot : atp pilot : cfi |
| Experience | flight time last 90 days : 150 flight time total : 10000 flight time type : 700 |
| ASRS Report | 434236 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other anomaly other |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | flight crew : rejected takeoff none taken : anomaly accepted |
| Consequence | other |
| Factors | |
| Maintenance | contributing factor : schedule pressure performance deficiency : inspection |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
Air carrier X was first leg of the day for me and the first officer. Following a normal briefing, we taxied to runway 25R. During taxi, wind was light (variable +/-5 KTS), but shifting 180 degrees, so a decision was made to use full 10 KT tailwind/reduced takeoff data. Initial portion of takeoff run was normal, except marginally more rudder corrections than usual we applied, due to slight deviations of nose during acceleration. Shortly after one nose deviation and subsequently correction a small, well defined yaw was noted, at approximately 125 KTS. Due to uncertainty over reason for yaw, an abort was initiated at approximately 130 KTS. Discussed situation with system aircraft maintenance control and local maintenance. Dispatch was notified through maintenance control. The subsequent flight to lax was normal, except after landing the nose steering seemed sloppy. Reported this observation to maintenance and had several conversations to determine the possible significance. Eventually, a write-up was entered into logbook so that maintenance could investigate further. Maintenance investigation is ongoing, however, I strongly suspect that sloppy nose steering coupled with normal rudder inputs and possible runway surface imperfections may have caused the small, sudden yaw of the aircraft. Callback conversation with reporter revealed the following information: reporter stated the aircraft was a B737-300 and on takeoff roll at 125 KTS the aircraft experienced a slight yaw input and the takeoff was aborted at 130 KTS. The reporter said the steering on the aircraft at all speeds was 'sloppy and wobbly' and later after maintenance taxi tested the aircraft it was discovered the nose gear trunnion fittings and bearings were worn beyond limits. The reporter said a bite test of the yaw damper coupler was made and the coupler was replaced. The reporter stated the flight data recorder was removed for examination but the results were not available to the reporter at this time.
Original NASA ASRS Text
Title: A B737-300 ON TKOF ROLL REJECTED THE TKOF AT 130 KTS DUE TO A SMALL WELL DEFINED YAW INPUT AND SLOPPY STEERING.
Narrative: ACR X WAS FIRST LEG OF THE DAY FOR ME AND THE FO. FOLLOWING A NORMAL BRIEFING, WE TAXIED TO RWY 25R. DURING TAXI, WIND WAS LIGHT (VARIABLE +/-5 KTS), BUT SHIFTING 180 DEGS, SO A DECISION WAS MADE TO USE FULL 10 KT TAILWIND/REDUCED TKOF DATA. INITIAL PORTION OF TKOF RUN WAS NORMAL, EXCEPT MARGINALLY MORE RUDDER CORRECTIONS THAN USUAL WE APPLIED, DUE TO SLIGHT DEVS OF NOSE DURING ACCELERATION. SHORTLY AFTER ONE NOSE DEV AND SUBSEQUENTLY CORRECTION A SMALL, WELL DEFINED YAW WAS NOTED, AT APPROX 125 KTS. DUE TO UNCERTAINTY OVER REASON FOR YAW, AN ABORT WAS INITIATED AT APPROX 130 KTS. DISCUSSED SIT WITH SYS ACFT MAINT CTL AND LCL MAINT. DISPATCH WAS NOTIFIED THROUGH MAINT CTL. THE SUBSEQUENT FLT TO LAX WAS NORMAL, EXCEPT AFTER LNDG THE NOSE STEERING SEEMED SLOPPY. RPTED THIS OBSERVATION TO MAINT AND HAD SEVERAL CONVERSATIONS TO DETERMINE THE POSSIBLE SIGNIFICANCE. EVENTUALLY, A WRITE-UP WAS ENTERED INTO LOGBOOK SO THAT MAINT COULD INVESTIGATE FURTHER. MAINT INVESTIGATION IS ONGOING, HOWEVER, I STRONGLY SUSPECT THAT SLOPPY NOSE STEERING COUPLED WITH NORMAL RUDDER INPUTS AND POSSIBLE RWY SURFACE IMPERFECTIONS MAY HAVE CAUSED THE SMALL, SUDDEN YAW OF THE ACFT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE ACFT WAS A B737-300 AND ON TKOF ROLL AT 125 KTS THE ACFT EXPERIENCED A SLIGHT YAW INPUT AND THE TKOF WAS ABORTED AT 130 KTS. THE RPTR SAID THE STEERING ON THE ACFT AT ALL SPDS WAS 'SLOPPY AND WOBBLY' AND LATER AFTER MAINT TAXI TESTED THE ACFT IT WAS DISCOVERED THE NOSE GEAR TRUNNION FITTINGS AND BEARINGS WERE WORN BEYOND LIMITS. THE RPTR SAID A BITE TEST OF THE YAW DAMPER COUPLER WAS MADE AND THE COUPLER WAS REPLACED. THE RPTR STATED THE FLT DATA RECORDER WAS REMOVED FOR EXAMINATION BUT THE RESULTS WERE NOT AVAILABLE TO THE RPTR AT THIS TIME.
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.