The below happened on the 29/03/15 and 30/03/15
On returning from a cross country flight PIC experienced a sudden yaw (rudder) to the right hand side. The aircraft subsequently went into a right hand turn and PIC was unable to correct with left rudder however gained enough control of the aircraft (with crossed controls). PIC declared an emergency and side slipped onto runway 30, landing without incident. LAME discovered that someone had changed the tensioning springs that were part of the rudder pedals to nose wheel link that returned the pedals to centre after a rudder input. The replacement spring had a much lower tension. LAME took the springs off the Ballarat Sierra and fitted them to the Bravo. The test flight with the CFI following the swap of springs resulted in perfect flight handling. There was no record of the springs being changed in the logbook and no one is aware of any modifications however explains why the aircraft was flying perfectly for years and then suddenly displayed abnormal behavior. Aircraft owner Repco, Bunnings Aerospace and other automotive suppliers.
Completing a check flight after inspection. Aircraft was on downwind RWY18 85 kts, straight and level. The aircraft rolled and yawed to the right without warning. PIC applied full left rudder and full power and the aircraft shuddered and recovered. Recovery was not instant but did return to level flight. Rudder required a lot of pressure to move much more than normal. Lost about 200 feet. Completed circuit and made a full stop landing without further incident. The Aircraft had suffered a similar incident on Sunday 29/3/2015. . Aircraft Grounded until fault identified and repaired. LAME discovered that someone had changed the tensioning springs that were part of the rudder pedals to nose wheel link that returned the pedals to centre after a rudder input. The replacement spring had a much lower tension. LAME took the springs off the Ballarat Sierra and fitted them to the Bravo. The test flight with the CFI following the swap of springs resulted in perfect flight handling. There was no record of the springs being changed in the logbook and no one is aware of any modifications however explains why the aircraft was flying perfectly for years and then suddenly displayed abnormal behavior. Aircraft owner Repco, Bunnings Aerospace and other automotive