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Sa-227AC captain reported multiple attempts to takeoff; but each was rejected because of directional control issues.
| Attributes | |
| ACN | 1301356 |
| Time | |
| Date | 201510 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | APA.Airport |
| State Reference | CO |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | SA-227 AC Metro III |
| Operating Under FAR Part | Part 135 |
| Flight Phase | Takeoff |
| Flight Plan | IFR |
| Person 1 | |
| Function | Pilot Flying Captain |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Ground Event / Encounter Other / Unknown |
Narrative:
On beginning of takeoff roll plane veered to left. Aborted takeoff; got back to center of runway; attempted takeoff again. Nose wheel steering off; nose wheel centered; advance power; plane veered left again; aborted a second time. Returned plane to center of runway; lined up again; held brakes advanced power to the same torque; around 50%; released brakes; plane veered left again. Aborted takeoff; returned to hangar. Wrote up 'plane will veer hard left at beginning of takeoff roll'.I have flown this plane before and it did veer left but was manageable. This time the first officer and I could [not] get plane to not veer left. I believe with the same torque on both engines the blade angle on the right engine is greater than the blade angle of the left engine. Would take a lot of throttle stagger to match the blade angles together on takeoff roll. What could be done is set the torque even use some sort stroboscope to calibrate the pitch angle to compare the two engines. There must be some way to measure the pitch of the prop at any given power setting. I believe the difference in pitch at given power settings causes asymmetric thrust. It's a combination throttle alignment and blade angle that causes the plane to veer left.
Original NASA ASRS Text
Title: SA-227AC Captain reported multiple attempts to takeoff; but each was rejected because of directional control issues.
Narrative: On beginning of takeoff roll plane veered to left. Aborted takeoff; got back to center of runway; attempted takeoff again. Nose wheel steering off; nose wheel centered; advance power; plane veered left again; aborted a second time. Returned plane to center of runway; lined up again; held brakes advanced power to the same torque; around 50%; released brakes; plane veered left again. Aborted takeoff; returned to hangar. Wrote up 'plane will veer hard left at beginning of takeoff roll'.I have flown this plane before and it did veer left but was manageable. This time the FO and I could [not] get plane to not veer left. I believe with the same torque on both engines the blade angle on the right engine is greater than the blade angle of the left engine. Would take a lot of throttle stagger to match the blade angles together on takeoff roll. What could be done is set the torque even use some sort stroboscope to calibrate the pitch angle to compare the two engines. There must be some way to measure the pitch of the prop at any given power setting. I believe the difference in pitch at given power settings causes asymmetric thrust. It's a combination throttle alignment and blade angle that causes the plane to veer left.
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.