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A B737 exhibited characteristics consistent with an excessively aft cg during the takeoff roll and on approach. The flight crew added a precautionary 20 KTS to the landing speeds.
| Attributes | |
| ACN | 1164085 |
| Time | |
| Date | 201404 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Takeoff |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Elevator Trim System |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 220 Flight Crew Total 15000 Flight Crew Type 5000 |
| Person 2 | |
| Function | First Officer Pilot Flying |
| Experience | Flight Crew Last 90 Days 270 Flight Crew Total 3700 Flight Crew Type 350 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Weight And Balance |
Narrative:
On the takeoff roll the nose came up and had to be manually held down with a stab trim of 4 ¼ [anu]. Heavy nose [down] pressure was needed to accelerate in the climb. After reaching 250 KTS the jet operated normally. An ACARS was sent to dispatch who said they would look into it. We decided to add 20 KTS to our [ref speed] as a precaution against an aft cg problem. On descent we were cleared direct trann and slow to 210 KTS. As the speed approached 210 with the autopilot engaged the trim started cycling down then up repeatedly; not being able to find center. Even going flaps 1 and then flaps 5 the trim continued to constantly cycle up then down. We turned off the autopilot and hand flew to the runway keeping our 20 KTS addition without further incident.
Original NASA ASRS Text
Title: A B737 exhibited characteristics consistent with an excessively aft CG during the takeoff roll and on approach. The flight crew added a precautionary 20 KTS to the landing speeds.
Narrative: On the takeoff roll the nose came up and had to be manually held down with a stab trim of 4 ¼ [ANU]. Heavy nose [down] pressure was needed to accelerate in the climb. After reaching 250 KTS the jet operated normally. An ACARS was sent to Dispatch who said they would look into it. We decided to add 20 KTS to our [Ref speed] as a precaution against an aft CG problem. On descent we were cleared direct TRANN and slow to 210 KTS. As the speed approached 210 with the autopilot engaged the trim started cycling down then up repeatedly; not being able to find center. Even going flaps 1 and then flaps 5 the trim continued to constantly cycle up then down. We turned off the autopilot and hand flew to the runway keeping our 20 KTS addition without further incident.
Data retrieved from NASA's ASRS site 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.