Sunday, December 7, 2014

ATSB Final Report into Trim System Malfunction on Toll Metro VH-UZI at Rockhampton Airport

The Australian Transport Safety Bureau (ATSB) has released its final report into what was initially thought to be a 'loading event' but was found to be a 'trim system malfunction' involving Toll Freight Aviation Metro III Expeditor VH-UZI at Rockhampton Airport on Wednesday 6 August.

VH-UZI receiving attention at Rocky after the incident  (File photo taken by 'IAD'  ©)

The ATSB found that the pilot of VH-UZI, conducted a usual pre-flight inspection and weight and balance calculations for a freight charter flight from Rockhampton to Townsville.

"During the subsequent take-off run, the pilot reported all indications and performance were normal passing 70 knots.  Passing V1, as the pilot increased the back pressure on the control yoke to rotate the aircraft for take-off, the control column felt heavy and the aircraft nose wheel did not lift off the ground. 

"The pilot continued to increase the back trim and back pressure on the control yoke and the ‘out of trim’ warning sounded. The pilot rejected the take-off, applied maximum braking and reverse thrust.
After taxiing the aircraft back to the parking bay, the pilot requested the freight be re-weighed. The pilot then recalculated the aircraft weight and balance with the actual freight distribution and found the centre of gravity slightly more forward than the original load sheet position.

"The pilot set the stabiliser trim gauge in the cockpit to read a nose up attitude, and then externally inspected the position of the stabiliser. He observed the stabiliser in a neutral position and therefore determined that the gauge did not accurately indicate the stabiliser position. The pilot assessed that the combination of the incorrectly loaded freight causing a more forward centre of gravity and the inaccurate stabiliser trim gauge led to the out of trim warning and overly heavy control pressure required for the attempted take-off.

"The stabilizer trim potentiometer in the aircraft was replaced which resolved the fault."

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