On 25 November 2009, an Ayres Corporation S2RT341 aircraft,
registered VH-NZB (Figure 1), was being operated on a ferry flight
from Parkes, New South Wales (NSW) to Batchelor, Northern Territory
(NT), with an initial intermediate stop at Longreach, Queensland
(Qld). While on final approach to Longreach, without warning, the
aircraft's nose pitched upward and an aerodynamic stall resulted.
The pilot, the sole occupant, regained control and the aircraft
landed safely.
A subsequent engineering investigation by the aircraft's
maintenance provider determined that the elevator push rods had
been fitted in the reverse order during recent maintenance, thus
restricting the amount of nose down elevator travel available to
the pilot.
The maintenance organisation advised the ATSB that, as a
result of this occurrence, it has initiated a number of safety
actions, including:
- exploring options for modifying the design of the
bellcrank assembly to ensure that the push rods can only be fitted
in the correct position - ensuring that all employees are aware of their
responsibilities when conducting dual maintenance inspections on
flight control systems.