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Flight crew of B737-200 surprised when aircraft rotates itself 15 KTS prior to V1. Reject takeoff and discover pitch trim misset.
| Attributes | |
| ACN | 632342 |
| Time | |
| Date | 200410 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : las.airport |
| State Reference | NV |
| Altitude | agl single value : 0 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : takeoff roll |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| ASRS Report | 632342 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time total : 6850 flight time type : 2100 |
| ASRS Report | 632341 |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : company policies non adherence : published procedure other anomaly conflict : ground less severe |
| Independent Detector | aircraft equipment other aircraft equipment : acft pitch controls |
| Resolutory Action | flight crew : regained aircraft control flight crew : rejected takeoff |
| Consequence | Other |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
I was acting as the PF. Approaching 130 KTS on takeoff, the aircraft started to pitch up. V1 was about 142 KTS. I de-rotated the aircraft. Seeing I was still below V1 and not being sure of the cause, I elected to reject the takeoff. The reject went well and I was able to clear the runway before the last intersection. We notified ATC, cleared the runway and started making calls to operations and maintenance while consulting the brake cooling charts. We later discovered that the trim was set at approximately 6.5 units. The trim sheet called for 3.9. Upon review, neither one of us could recall doing or not doing the before start checklist 'below the line.' the pitch up seemed substantially more than what a 3 unit out-of-trim would cause. The aircraft rotated on its own around or prior to 130 KTS, more than 15 KTS below V1. Aircraft was full and may have had a center of gravity more aft than advertised compounding the out-of-trim setting.
Original NASA ASRS Text
Title: FLT CREW OF B737-200 SURPRISED WHEN ACFT ROTATES ITSELF 15 KTS PRIOR TO V1. REJECT TKOF AND DISCOVER PITCH TRIM MISSET.
Narrative: I WAS ACTING AS THE PF. APCHING 130 KTS ON TKOF, THE ACFT STARTED TO PITCH UP. V1 WAS ABOUT 142 KTS. I DE-ROTATED THE ACFT. SEEING I WAS STILL BELOW V1 AND NOT BEING SURE OF THE CAUSE, I ELECTED TO REJECT THE TKOF. THE REJECT WENT WELL AND I WAS ABLE TO CLR THE RWY BEFORE THE LAST INTXN. WE NOTIFIED ATC, CLRED THE RWY AND STARTED MAKING CALLS TO OPS AND MAINT WHILE CONSULTING THE BRAKE COOLING CHARTS. WE LATER DISCOVERED THAT THE TRIM WAS SET AT APPROX 6.5 UNITS. THE TRIM SHEET CALLED FOR 3.9. UPON REVIEW, NEITHER ONE OF US COULD RECALL DOING OR NOT DOING THE BEFORE START CHKLIST 'BELOW THE LINE.' THE PITCH UP SEEMED SUBSTANTIALLY MORE THAN WHAT A 3 UNIT OUT-OF-TRIM WOULD CAUSE. THE ACFT ROTATED ON ITS OWN AROUND OR PRIOR TO 130 KTS, MORE THAN 15 KTS BELOW V1. ACFT WAS FULL AND MAY HAVE HAD A CTR OF GRAVITY MORE AFT THAN ADVERTISED COMPOUNDING THE OUT-OF-TRIM SETTING.
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.